Epilim® - data sheet

DATA SHEET
EPILIM®
NAME OF THE MEDICINE
Non-proprietary name
Chemical name
Chemical Structure
CAS Registry Number
DESCRIPTION
Sodium valproate. Sodium valproate is a white, odourless, crystalline powder with a saline taste. It is highly soluble in water and alcohol. Its molecular weight is 166. It is quite dissimilar to other established anticonvulsants such as barbiturates, hydantoins, succinamides, oxazolidinediones and acetylureas in that it has no nitrogen or aromatic moiety. Crushable: includes maize starch, kaolin, silicon dioxide and magnesium stearate. Enteric-Coated: includes povidone, purified talc, magnesium stearate, calcium silicate, anhydrous citric acid, macrogol 6000, hypromellose, polyvinyl acetate phthalate, diethyl phthalate, stearic acid, amaranth aluminium lake, indigo carmine aluminium lake, titanium dioxide. Sugar-Free Liquid: includes hydroxyethylcellulose, saccharin sodium, sorbitol solution (70%) (non-crystallising), anhydrous citric acid, brilliant scarlet 4R, purified water, flavour imitation cherry 17.40.0740, sodium methyl hydroxybenzoate and sodium propyl hydroxybenzoate. Syrup: includes sucrose, sorbitol, saccharin sodium, brilliant scarlet 4R, purified water, flavour imitation cherry 17.40.0740, sodium methyl hydroxybenzoate and sodium propyl hydroxybenzoate. Intravenous (IV): each pack contains one glass vial of 400 mg sodium valproate freeze-dried powder and one glass ampoule containing 4 mL of solvent (Water for Injections). PHARMACOLOGY
Class: Anticonvulsant, antipsychotic.
Site and Mode of Action: The mode of action of Epilim has not been fully established. Its
anticonvulsant effect is attributed to the blockade of voltage dependent Na+ channels and
increased brain levels of -aminobutyric acid (GABA). The GABA-ergic effect is also believed to
possibly contribute towards the antimanic properties of sodium valproate.
In animals, Epilim raises cerebral and cerebellar levels of the inhibitory synaptic transmitter, GABA, possibly by inhibiting GABA degradative enzymes, such as GABA transaminase and/or succinic semialdehyde dehydrogenase and/or by inhibiting the reuptake of GABA by neuronal cells. Epilim exhibits marked anticonvulsant activity in animals, demonstrated by the various tests used to detect antiepileptic activity. Epilim appears to have no significant hypnotic effect (an incidence of about 0.2% was noted for drowsiness in a survey of unwanted effects), nor does it have any significant action on the autonomic nervous system, respiration, blood pressure, renal function or body temperature. It does have a spasmolytic action on the isolated ileum preparation but no effect on the nictitating membrane. Pharmacodynamics
In epilepsy: Epilim has been shown to be effective in the treatment of absence seizures (petit
mal), tonic-clonic seizures (grand mal) and myoclonic seizures. It has also been shown to be
effective in patients with partial (focal) seizures. Epilim appears to have less sedative effect than
conventional antiepileptic drugs and this, together with the reduction in fit frequency in children,
has often led to improvements in alertness and performance in school.
In bipolar disorder: In one study valproate has been shown to be significantly more effective
than placebo in the treatment of acute mania and has been reported to be comparable to lithium.
Potential medicine interactions likely to be relevant to valproate in the management of patients
with mania are outlined under Interactions with other medicines. Although the dosage of
sodium valproate varied considerably among the controlled studies, a fixed initial dose was used
after which dosage was determined by serum levels.
Pharmacokinetics
Absorption: Valproic acid is rapidly and almost completely absorbed in fasting patients following oral dosing with Epilim plain tablets, syrup and sugar-free liquid, with peak blood levels occurring within 1 to 4 hours. Absorption of valproic acid from the enteric-coated tablets given to fasting subjects is delayed with peak blood levels occurring within 3 to 7 hours. Overall absorption is not significantly altered by co-administration with milk products, but is delayed if the medicine is taken with food. However, the extent of absorption is not affected. Local gastric irritation may occur with the plain tablets, sugar-free liquid or syrup when administered on an empty stomach, due to transformation of sodium valproate into valproic acid. Gastric irritation is less likely to occur with the enteric-coated tablets. In most adult patients, daily doses of 1,200 to 1,500 mg result in therapeutic plasma levels of 50 to 100 microgram/mL (0.35 to 0.69 mmol/L). However, correlation between the daily dose per bodyweight and plasma levels of drug has been poor as this reported range might depend on time of sampling and presence of co medication. The percentage of free (unbound) drug is usually between 6% and 15% of the total plasma levels. An increased incidence of adverse effects may occur with plasma levels above the effective therapeutic range. The pharmacokinetic profile of Epilim Powder for IV Injection differs from that of oral Epilim preparations. As expected, after intravenous and oral dosage (enteric-coated tablets) of Epilim (400 mg), Tmax is reached sooner following intravenous administration (7.3 ± 2.6 min) than after oral administration (227.7 ± 59.2 min) and Cmax is higher after intravenous dosage (55.4 ± 9.38 microgram/mL) than after oral administration (39.1 ± 3.51 microgram/mL). The bioavailability of Epilim enteric-coated (EC) tablets is only slightly less than that of intravenous Epilim with a mean AUC ratio of 100:87 for intravenous to oral forms respectively. The distribution, metabolism, excretion and elimination of intravenous Epilim are not different to orally administered Epilim. In most adult patients, daily doses of 1,200 to 1,500 mg result in therapeutic plasma levels of 50 to 100 microgram/mL (0.35 to 0.69 mmol/L). However, correlation between the daily dose per bodyweight and plasma levels of drug has been poor. Oral and IV
Distribution: Distribution of sodium valproate is rapid and most likely restricted to the circulation and rapidly exchangeable extracellular water. CSF and breast milk levels were found to be 5 to 15% and about 1 to 10% of plasma levels, respectively. Valproic acid shows non-linear kinetics, due to concentration-dependent plasma protein binding as well as a relatively short half-life. The half-life of sodium valproate is usually reported to be within the range 8-20 hours. It is usually shorter in children. Epilim is approximately 90% bound to plasma proteins but only 60% to albumin. However, if the plasma level of valproic acid rises above 120 microgram/mL or if the serum albumin concentration is lowered, the binding sites may become saturated, causing the amount of free drug to rise rapidly, out of proportion to any increase in dosage. Epilim may displace phenobarbitone or phenytoin from plasma protein binding sites. Saliva levels of Epilim are poorly correlated with those in plasma in contrast to the good correlation found for other antiepileptics. In animals, the drug crosses the placenta. Metabolism: Its metabolism is complex; the major elimination pathway is via glucuronidation (40-60%). The remainder is largely metabolised via oxidation pathways, -oxidation accounting for 30-40% and w-oxidation (cytochrome P450 dependent), the remaining fraction. Only 1 to 3% of the ingested dose is found to be excreted unchanged in the urine. Excretion: Sodium valproate is almost completely metabolised prior to excretion. Plasma half-
life is variable but generally appears to be 8 to 12 hours (range 3.84 to 15.77 hours). It may be
shorter in patients receiving other anticonvulsants or in children and patients receiving the
medicine for long periods. In cases of overdose, long half-lives up to 30 hours have been
reported. Antipsychotic agents or antidepressants including MAOIs, tricyclics and SSRIs co-
administered with sodium valproate may result in competitive metabolism or enzyme inhibition,
thereby increasing valproate levels (see Interactions with other medicines).
Clinical Trials
In epilepsy: Epilim’s efficacy in this therapeutic indication is widely known and recognised. In bipolar disorder: There have been at least five double-blind trials comparing sodium valproate or the bioequivalent active, divalproex sodium with either placebo and/or lithium in the treatment of mania. Only one of these trials was of adequate size. Bowden et al (1994) demonstrated most convincingly the superior effectiveness of valproate as compared to placebo in the treatment of acute mania. Marked improvement, defined as at least 50% improvement on the Manic Syndrome Subscale of the Mania Rating Scale occurred in 48% of valproate-treated patients and 25% of placebo-treated patients respectively (p=0.0040). Comparable efficacy to lithium in this study was reported. Marked improvement, defined as at least 50% improvement on the Manic Syndrome Subscale of the Mania Rating Scale, occurred in a similar number of patients receiving sodium valproate and lithium, 48% and 49% respectively. INDICATIONS
Epilepsy: Primary generalised epilepsy (petit mal absences, various forms of myoclonic
epilepsy and tonic-clonic grand mal seizures). Partial (focal) epilepsy either alone or as adjuvant
therapy.
Bipolar Disorder: For the treatment of manic episodes, maintenance and prophylactic
treatment of bipolar disease.
Epilim IV: The treatment of patients with epilepsy or bipolar disorder, who would normally be
maintained on oral sodium valproate, and for whom oral therapy is temporarily not possible.
CONTRAINDICATIONS
Pregnancy (see PRECAUTIONS). Pre-existing, acute or chronic hepatic dysfunction or family
history of severe hepatitis, particularly medicine related. Known hypersensitivity to the medicine.
Known urea cycle disorders (see PRECAUTIONS). Known hepatic porphyria.
Epilim IV should not be injected intramuscularly as it may produce tissue necrosis. PRECAUTIONS
1. Use with caution in the following circumstances: Pancreatitis: Severe pancreatitis, which may result in fatalities, has been very rarely reported.
Some cases have occurred shortly after initial use while others have occurred after several
years of use. There have also been cases in which pancreatitis recurred after rechallenge with
sodium valproate. Some of the cases have been described as haemorrhagic with a rapid
progression from initial symptoms to death. In clinical trials, there were two cases of pancreatitis
without alternative aetiology in 2416 patients, representing 1044 patient-years experience.
Young children are at particular risk but this risk decreases with increasing age. Severe seizures, neurological impairment or anticonvulsant polytherapy may be risk factors. Hepatic failure with pancreatitis increases the risk of fatal outcome. Patients and guardians should be warned that acute abdominal pain, nausea, vomiting, and/or anorexia can be symptoms of pancreatitis that require prompt medical attention. If pancreatitis is diagnosed, sodium valproate should be discontinued and alternative treatment for the underlying medical condition initiated as clinically indicated. Hepatic dysfunction: Severe liver damage and/or hepatic failure resulting in fatalities have
occurred in patients whose treatment included valproic acid or sodium valproate. Patients most
at risk are those on multiple anticonvulsant therapy and children, particularly those under the
age of 3 years and those with congenital metabolic or degenerative disorders, organic brain
disease or severe seizure disorders associated with brain damage and/or mental retardation.
The incidents usually occurred during the first six months of therapy, the period of maximum risk being 2 to 12 weeks, and usually involved multiple anticonvulsant therapy. Monotherapy is to be preferred in this group of patients. After the age of 3 years, the risk is significantly reduced and it progressively decreases with age. In most cases, such liver damage occurred during the first 6 months of therapy. Clinical symptoms are usually more helpful than laboratory investigations in the early stages of hepatic failure. Serious or fatal hepatotoxicity may be preceded by nonspecific symptoms, usually of sudden onset, such as loss of seizure control, malaise, asthenia, weakness, lethargy, facial oedema, anorexia, vomiting, abdominal pain, drowsiness, jaundice. In patients with epilepsy, recurrence of seizures can occur. These are an indication for immediate withdrawal of the medicine. Patients should be monitored closely for the appearance of these symptoms and should be instructed to report any such signs to the clinician for investigation should they occur. Investigations including clinical examination and laboratory assessment of liver functions should be undertaken immediately. Although published evidence does not establish which, if any investigation could predict this possible adverse effect, liver function tests should be performed prior to therapy and frequently thereafter until 6 months after the controlling dose is reached, when less frequent monitoring may be appropriate. It is also advisable to monitor tests that reflect protein synthesis, e.g. prothrombin time, serum fibrinogen and albumin levels, especially in those who seem most at risk and those with a prior history of hepatic disease. As with most antiepileptic drugs, a slight increase in liver enzymes may be noted, particularly at the beginning of therapy. They are transient and isolated. More extensive biological investigations (including prothrombin rate) are recommended in those patients. An adjustment of dosage may be considered when appropriate and tests should be repeated as necessary. Raised liver enzymes are not uncommon during treatment with Epilim, particularly if used in
conjunction with other anticonvulsants, and are usually transient or respond to dosage
reduction. Patients with such biochemical abnormalities should be reassessed clinically and
tests of liver function should be monitored more frequently. Among the usual investigations, tests
which reflect protein synthesis particularly prothrombin rate, are most relevant. An abnormally
low prothrombin rate, particularly in association with other relevant abnormalities (significant
decrease in fibrinogen and coagulation factors; increased bilirubin level and raised
transaminases) requires cessation of treatment and the substitution of alternative medicines to
avoid precipitating convulsions. Uneventful recovery has been recorded in several cases where
therapy with Epilim has ceased, but death has occurred in some patients in spite of the medicine
being withdrawn. Any concomitant use of salicylates should be stopped, since they employ the
same metabolic pathway.
Impaired renal function: Lower doses may be required since free drug levels may be high
owing to lowered serum albumin and poor urinary excretion of free drug metabolites. As
monitoring of plasma concentrations may be misleading, dosage should be adjusted according
to clinical monitoring.
Diabetes: Care should be taken when treating diabetic patients with Epilim syrup which
contains sucrose 3.6 g/5 mL. In such patients, Epilim Sugar-Free Liquid would be a preferable
medication. See also Interference with Clinical and Other Tests.
Dilutions: If it is necessary to dilute the syrup, the recommended diluent is Syrup BP. Syrup
containing sulfur dioxide as a preservative should not be used. The diluted product will have a
14-day shelf-life. The Sugar-Free Liquid should not be diluted.
Lupus erythematosus: Although immune disorders have been noted only exceptionally during
the use of Epilim, the potential benefit of Epilim should be weighed against its potential risk in
patients with systemic lupus erythematosus.
Hyperammonaemia: When urea cycle enzymatic deficiency is suspected, metabolic
investigations should be performed prior to treatment because of the risk of hyperammonaemia
with valproate.
Hyperammonaemia, which may be present in the absence of abnormal liver function tests, can
occur in patients during treatment with sodium valproate. This may occasionally present
clinically, with or without lethargy or coma, as vomiting, ataxia and increasing clouding of
consciousness. Should these symptoms occur, hyperammonaemic encephalopathy should be
considered (see Urea Cycle Disorders) and Epilim should be discontinued.
Urea Cycle Disorders (UCD): Hyperammonaemic encephalopathy, sometimes fatal, has been
reported following initiation of valproate therapy in patients with urea cycle disorders, a group of
uncommon genetic abnormalities, particularly ornithine transcarbamylase deficiency. Prior to
the initiation of valproate therapy, evaluation for UCD should be considered in the following
patients: 1) those with a history of unexplained encephalopathy or coma, encephalopathy
associated with a protein load, pregnancy-related or postpartum encephalopathy, unexplained
mental retardation, or history of elevated plasma ammonia or glutamine; 2) those with cyclical
vomiting and lethargy, episodic extreme irritability, ataxia, low BUN, or protein avoidance; 3)
those with a family history of UCD or a family history of unexplained infant deaths (particularly
males); 4) those with other signs or symptoms of UCD. Patients who develop symptoms of
unexplained hyperammonaemic encephalopathy while receiving valproate therapy should
receive prompt treatment (including discontinuation of valproate therapy) and be evaluated for
underlying urea cycle disorders.
Ornithine Transcarbamylase (OTC) Deficiency: The females who are heterozygous for OTC
deficiency have a spectrum of clinical and biochemical findings, depending on the extent of
inactivation of the X-chromosome. Females may show a range of symptoms due to
hyperammonaemia which, may be episodic, and therefore difficult to diagnose. The acute
symptoms include headaches, vomiting, irritability, bizarre behaviour, lethargy, ataxia, tremors,
seizures (generalised tonic-clonic or focal) and coma. Valproate may precipitate
hyperammonaemia symptoms in those who have pre-existing OTC deficiency. As the
symptoms may include seizures, any female with valproate-associated symptomatic
hyperammonaemia should be evaluated for OTC deficiency. Investigations should include
measurement of plasma amino acids and the immediate cessation of valproate should result in
clinical improvement.
Surgery: Prolongation of bleeding time, sometimes with thrombocytopenia, has occurred with
Epilim therapy. Platelet function should be monitored before surgery is undertaken in patients
receiving Epilim.
Other: Blood tests (blood cell count, including platelet count, bleeding time and coagulation tests) are recommended prior to initiation of therapy or before surgery, and in case of spontaneous bruising or bleeding. Suicidal Behaviour and Ideation: Antiepileptic drugs, including sodium valproate increase the
risk of suicidal thoughts or behaviour in patients taking these drugs for any indication. Patients
treated with any AED for any indication should be monitored for the emergence or worsening of
depression, suicidal thoughts or behaviour, and/or any unusual changes in mood or behaviour.
Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomised to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behaviour compared to patients randomised to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behaviour or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behaviour for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide. The increased risk of suicidal thoughts or behaviour with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behaviour beyond 24 weeks could not be assessed. The risk of suicidal thoughts or behaviour was generally consistent among drugs in the data analysed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5-100 years) in the clinical trials analysed. The following Table shows absolute and relative risk by indication for all evaluated AEDs. Indication Placebo
patients
Drug patients with Relative Risk:
Relative Difference:
events/1000 patients
events/1000 patients
Incidence of events in Additional Drug
Drug
patients with events
patients/Incidence in per 1000 patients
Placebo patients
The relative risk for suicidal thoughts or behaviour was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications. Anyone considering prescribing sodium valproate or any other AED must balance this risk with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behaviour. Should suicidal thoughts and behaviour emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated. Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behaviour and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behaviour, or the emergence of suicidal thoughts, behaviour, or thoughts about self-harm. Behaviours of concern should be reported immediately to the treating doctor. Abrupt withdrawal: The possible risk of fits after sudden cessation of Epilim should be borne in
mind. If it is the only anticonvulsant used and has to be withdrawn for more than 12 hours
because of surgery, control of epilepsy may be lost.
Carbapenem antibiotics: The concomitant use of sodium valproate and carbapenem antibiotics is not recommended (see also Interactions with other medicines). Pharmaceutical precautions: Epilim tablets are hygroscopic and must be kept in protective foil
until taken. See also PRESENTATION AND STORAGE CONDITIONS.
Thrombocytopenia: Because of reports of thrombocytopenia, inhibition of the secondary phase
of platelet aggregation, and abnormal coagulation parameters, platelet counts and coagulation
tests are recommended before initiating therapy and at periodic intervals. Evidence of
haemorrhage, bruising or a disorder of haemostasis/coagulation is an indication for reduction of
Epilim dosage or withdrawal of therapy.
Ornithine Transcarbamylase (OTC) Deficiency: A familial history of infant mortality or patient
history of OTC deficiency, or of seizures or coma in the presence of mental retardation suggests
the need to exclude OTC deficiency.
Weight Gain: Patients should be warned of the risk of weight gain at the initiation of therapy,
and appropriate strategies should be adopted to minimise the risk.
Women of child bearing potential:
This medicine should not be used in women of child-bearing potential unless clearly necessary (i.e. in situations where other treatments are ineffective or not tolerated). This assessment is to be made before sodium valproate is prescribed for the first time, or when a woman of child bearing potential treated with sodium valproate plans a pregnancy. Women of child-bearing potential must use effective contraception during treatment. Use in Pregnancy (Category D)
Before Epilim is prescribed for use in women with epilepsy of any form, who could become pregnant, they should receive specialist advice. Due to the potential risks to the foetus, the benefits of Epilim should be weighed against the risks. When treatment with Epilim is deemed necessary, precautions to minimise the potential teratogenic risk should be followed. Overall, the risk of having a child with abnormalities as a result of antiepileptic medication is far outweighed by the dangers to the mother and foetus of uncontrolled epilepsy. Notwithstanding the potential risks, no sudden discontinuation of antiepileptic therapy should be undertaken, without reassessment of the risks and benefits, as this may lead to breakthrough seizures which could have serious consequences for both the mother and the foetus. If after careful evaluation of the risks and benefits, sodium valproate treatment is to be continued during pregnancy, it is recommended to use sodium valproate in divided doses over the day at the lowest effective dose. In bipolar disorder, cessation of sodium valproate should be considered. During pregnancy, maternal tonic clonic seizures and status epilepticus with hypoxia carry a particular risk of death for mother and for the unborn child. The risk of a mother with epilepsy giving birth to a baby with an abnormality is about three times that of the normal population. An increased incidence of minor or major malformations including neural tube defects, craniofacial defects, malformation of the limbs, cardiovascular malformations, hypospadias and multiple anomalies involving various body systems has been reported in children born to mothers treated with valproate. Women treated with Epilim IV have a potentially increased risk of giving birth to a baby with an abnormality due to the higher Cmax of the intravenous formulation compared with the oral formulation. Mothers taking more than one anticonvulsant medicine might have a higher risk of having a baby with a malformation than mothers taking one medicine. Sodium valproate (valproic acid), if taken in the first trimester of pregnancy, is suspected of causing an increased risk of neural tube defects (especially spina bifida) in the exposed foetus. This has been estimated to be in the region of 1-2%. Some data have suggested an association between in-utero valproate exposure and the risk of impaired cognitive function, including developmental delay (frequently associated with craniofacial abnormalities), particularly of verbal IQ. Developmental delay has been very rarely reported in children born to mothers with epilepsy. It is not possible to differentiate what may be due to genetic, social, environmental factors, maternal epilepsy or antiepileptic treatment. Autism spectrum disorders have also been reported in children exposed to valproate in-utero. Both valproate monotherapy and valproate polytherapy are associated with abnormal pregnancy outcome. Available data suggest that antiepileptic polytherapy including valproate is associated with a higher risk of abnormal pregnancy outcome than valproate monotherapy. In view of this data, the following recommendation should be taken into consideration: This medicine should not be used during pregnancy and in women of child-bearing potential unless clearly necessary, that is, in situations where other treatments are ineffective or not tolerated. This assessment is to be made before sodium valproate is prescribed for the first time, or when a woman of child-bearing potential treated with sodium valproate plans a pregnancy. Women of child-bearing potential must use effective contraception during treatment. Women of child-bearing potential should be informed of the risks and benefits of the use of valproate during pregnancy. It is recommended that women of child-bearing potential taking sodium valproate should:  receive counselling with regard to the risk of foetal abnormalities;  have their drug treatment reviewed before conception. This may involve dose adjustments or alternative therapy options. If sodium valproate is to be continued, monotherapy should be used if possible at the lowest effective dose given in divided doses, as risk of abnormality is greater in women taking combined medication and in women taking a higher total daily dose;  undergo routine ultrasound and amniocenteses for specialist prenatal diagnosis of such  take folic acid supplementation (5mg daily) for at least 4 weeks prior to and 12 weeks after conception as folic acid may have a role in the prevention of neural tube defects in infants of women taking antiepileptic therapy. It is recommended that in bipolar disorders indication, cessation of valproate therapy should be considered. There have been rare reports of haemorrhagic syndrome in neonates whose mothers have taken sodium valproate during pregnancy. This syndrome is related to thrombocytopenia, hypofibrinaemia and/or to a decrease in other coagulation factors. Afibrinaemia has also been reported and may be fatal. Hypofibrinaemia is possibly associated with a decrease of coagulation factors. Phenobarbital and other enzyme inducers may also induce haemorrhagic syndrome. Platelet count, fibrinogen plasma level and coagulation status should be investigated in neonates. Cases of hypoglycaemia have been reported in neonates whose mothers have taken valproate during the third trimester of the pregnancy. Cases of hypothyroidism have been reported in neonates whose mothers have taken valproate during pregnancy. Use in Lactation
Epilim is excreted in breast milk. Concentrations in breast milk have been reported to be 1 to 10% of serum concentration. It is not known what effect this would have on a breast-fed infant. As a general rule, breastfeeding should not be undertaken whilst a patient is receiving Epilim. Paediatric Use
The potential benefit of Epilim should be weighed against the risk of liver damage or pancreatitis in such patients prior to initiation of therapy (see PRECAUTIONS). The concomitant use of salicylates should be avoided in children under 3 due to the risk of liver toxicity and the concomitant use of barbiturates may require dosage adjustment (see ‘Interactions with other medicines’). Monotherapy is recommended in children under 3 years of age, when prescribing Epilim. Young children are at particular risk for pancreatitis, however this risk decreases with increasing age. The safety and efficacy of sodium valproate for the treatment of manic episodes in bipolar disorder have not been evaluated in patients aged less than 18 years. Carcinogenicity/Mutagenicity
Carcinogenesis: Sodium valproate was administered in the diet to Sprague-Dawley rats and
ICR (HA/ICR) mice at approximate dosage levels of 0, 80 and 160 mg/kg/day for up to 2 years.
There was equivocal evidence of an increased incidence of subcutaneous fibrosarcomas in male
rats and of bronchoalveolar adenomas in male mice. The presence of these tumours was not
considered to be biologically significant because of the published variable incidence of
spontaneously occurring fibrosarcomas and pulmonary adenomas in rats and mice respectively
and the fact that statistical significance of tumour incidence was only attained in males. The
significance of these findings for humans is unknown at present.
Toxicology: No significant toxic effects were seen in rats receiving 270 mg/kg/day for 3 months
or in dogs receiving 90 mg/kg/day for 12 months. At higher doses sedation, ataxia and various
histopathological effects (testicular atrophy and reduction in lymphoid tissue) were observed at
levels of 256 to 568 microgram/mL (1.78 to 3.94 mmol/L).
Testicular function: Epilim has been shown to cause atrophy of the seminiferous epithelium
with impairment of spermatogenesis, and to cause a decrease of the testicular weight of adult
rats and of offspring of female rats, when administered in high doses. On the other hand, a
reproductive study carried out in rats with similarly high doses in both sexes has not shown any
evidence of impaired fertility. The relevance of these findings to humans is not clear.
Interactions with other medicines
Caution is advised when using Epilim in combination with newer anti-epileptics whose pharmacodynamics may not be well established. a. Effects of valproate on other medicines: sodium valproate is an inhibitor of a variety of
hepatic enzymes, including cytochrome P450, glucuronyl transferase and epoxide hydrolase,
and may displace various drugs from plasma protein binding sites. The following list provides
information about potential effects of valproate co-administration on a range of commonly
prescribed medications. The list is not exhaustive, as new interactions may be reported.
Alcohol: Valproic acid may potentiate the CNS depressant activity of alcohol. Alcohol intake is
not recommended during treatment with valproate.
Antiepileptic drugs: Several antiepileptic drugs often used in conjunction with valproate (eg
phenytoin, carbamazepine, phenobarbitone) have the ability to increase the intrinsic clearance of
valproate, presumably by enzymatic induction of metabolism.
Carbamazepine: Valproate may displace carbamazepine from protein binding sites and may
inhibit the metabolism of both carbamazepine and its metabolite carbamazepine 10, 11 epoxide
and consequently potentiate toxic effects of carbamazepine. Clinical monitoring is
recommended especially at the beginning of combined therapy, with dosage adjustment when
appropriate.
Lamotrigine: Sodium valproate reduces lamotrigine metabolism and increases mean half life by
nearly two-fold. This interaction may lead to increased lamotrigine toxicity, in particular serious
skin rashes. Clinical monitoring is recommended and lamotrigine dosage should be decreased
as appropriate.
Phenobarbitone: Sodium valproate may block the metabolism of barbiturates causing an
increase in phenobarbitone plasma levels, which, particularly in children, may be associated with
sedation. Combination of sodium valproate and phenobarbitone can cause CNS depression
without significant elevation of serum level of either drug. Therefore, clinical monitoring is
recommended throughout the first 15 days of combined treatment with immediate reduction of
phenobarbitone doses if sedation occurs and determination of phenobarbitone plasma levels
when appropriate. A reduction in the dose of phenobarbitone and/or valproate may be necessary
and this should also be borne in mind if medicines that are metabolised to phenobarbitone (e.g.
primidone, methylphenobarbitone) are given with sodium valproate.
Phenytoin: There have been reports of breakthrough seizures occurring with the combination
of sodium valproate and phenytoin. Most reports have noted a decrease in total plasma
phenytoin concentration, however increases in total phenytoin levels have been reported. An
initial fall in total phenytoin levels with subsequent increase in phenytoin levels has also been
reported. In addition, a decrease in total serum phenytoin with an increase in the free versus
protein bound phenytoin levels has been reported with possible overdose symptoms (valproic
acid displaces phenytoin from its plasma protein binding sites and reduces its hepatic
catabolism). Therefore, clinical monitoring is recommended. When phenytoin plasma levels are
determined, the free form should be evaluated. The dosage of phenytoin may require adjustment
when given in conjunction with valproate as required by the clinical situation.
Medicines with extensive protein binding: The concomitant administration of sodium
valproate with medicines that exhibit extensive protein binding (e.g. aspirin, carbamazepine,
phenytoin, warfarin) may result in alteration of serum drug levels.
Anticoagulants: The effect of Epilim on anticoagulants which modify platelet function is
unknown (see ADVERSE EFFECTS). Caution is recommended when administering
anticoagulants and other products which have anticoagulant properties (e.g. warfarin and
aspirin).
Ethosuximide: The interaction between ethosuximide and valproate is not normally of clinical
significance. There is evidence that sodium valproate may inhibit ethosuximide metabolism,
especially in the presence of other anticonvulsants. Patients receiving this combination should
be monitored clinically.
Oral contraceptives: The enzyme inducing effect of valproate is appreciably less than that of
certain other anticonvulsants and loss of efficacy of oral contraceptive agents does not appear to
be a problem.
Psychotropic agents: Epilim may potentiate the effects of other psychotropics such as MAOIs,
neuroleptics, benzodiazepines and other antidepressants, therefore clinical monitoring is
advised and the dose of these medicines should be reduced accordingly.
Clonazepam: The concomitant use of sodium valproate and clonazepam may produce absence
status.
Clozapine: Caution is advised during concomitant administration as competitive protein binding
may potentiate an increase in clozapine or valproate levels.
Diazepam: Sodium valproate displaces diazepam from its plasma binding sites and inhibits its
metabolism. Monitoring of free diazepam levels may be necessary if the patient becomes
sedated.
Lorazepam: A decrease in lorazepam plasma clearance may occur with concomitant
administration of sodium valproate.
Midazolam: Free plasma midazolam may increase in patients receiving valproate. It appears
likely that sodium valproate displaces midazolam from its plasma binding sites, potentially
leading to an increase of the midazolam response.
Primidone: Valproate increases primidone plasma levels with exacerbation of its adverse
effects (such as sedation); these signs cease with long-term treatment. Clinical monitoring is
recommended especially at the beginning of combined therapy with dosage adjustment when
appropriate.
Zidovudine: Valproate may raise zidovudine plasma concentrations leading to increased
zidovudine toxicity.
Tricyclic antidepressants: Sodium valproate may inhibit the metabolism of tricyclic
antidepressants. Clinical monitoring of free antidepressant levels may be necessary.
Other medicines: There was no notable interaction between valproate and lithium.
b. Effects of other medicines on valproate: the dosage of Epilim may need to be increased
by 5 to 10 mg/kg/day when used in combination with medicines which induce hepatic enzymes
and thereby increase the clearance of valproate. In contrast, medicines that are inhibitors of
cytochrome P450, may be expected to have only a minor effect on valproate clearance as
cytochrome P450 mediated microsomal oxidation is a relatively minor secondary metabolic
pathway to glucuronidation and ß-oxidation. The list is not exhaustive, as new interactions may
be reported.
Aspirin: Concomitant administration of sodium valproate and aspirin may result in displacement
of valproate from protein binding sites, resulting in a rise in free levels. In addition, aspirin
appears to inhibit the metabolism of valproate. Thus caution is advisable when patients on
sodium valproate are prescribed aspirin. Furthermore, patients requiring long-term aspirin
therapy may require a reduction in dosage of sodium valproate.
Felbamate: Felbamate may increase valproate serum concentrations. Valproate dosage should
be monitored when given in combination with felbamate. Valproic acid may decrease the
felbamate mean clearance by up to 16%.
Phenobarbitone, Phenytoin and Carbamazepine: These medicines can decrease steady-
state valproate levels in patients by increasing the intrinsic clearance of valproate, presumably
through enzymic induction of metabolism. The half-life is significantly reduced in patients on
polytherapy with these medicines. Dosages should be adjusted according to clinical response
and blood levels in case of combined therapy.
Antidepressants: Antidepressants (including MAOIs, tricyclic antidepressants and SSRIs) may
have the potential to inhibit the metabolism of valproate via the cytochrome P450 system.
However, there is not expected to be any significant interaction within normal therapeutic doses.
Antidepressants can lower the seizure threshold of non-stabilised epileptic patients, and so
careful and regular monitoring of their condition is indicated.
Clozapine: Caution is advised during concomitant administration as competitive protein binding
may potentiate an increase in clozapine or valproate levels.
Chlorpromazine: Chlorpromazine may inhibit the metabolism of valproate.
Fluoxetine: Fluoxetine may inhibit the metabolism of valproate as it does with tricyclic
antidepressants, carbamazepine and diazepam.
Mefloquine: Mefloquine increases valproic acid metabolism and has a convulsing effect;
therefore epileptic seizures may occur in cases of combined therapy.
Cimetidine or Erythromycin: Valproate serum levels may be increased (as a result of reduced
hepatic metabolism) in case of concomitant use with cimetidine or erythromycin.
Carbapenem antibiotics: Decreases in blood levels of valproic acid have been reported when
it is co-administered with carbapenem agents resulting in a 60-100 % decrease in valproic acid
levels in about two days. Due to the rapid onset and the extent of the decrease, co-
administration of carbapenem agents in patients stabilised on valproic acid should be avoided. If
treatment with these antibiotics cannot be avoided close monitoring of valproate blood level
should be performed.
Cholestyramine: May decrease the absorption of valproate.
Vitamin K dependent factor anticoagulant: Close monitoring of prothrombin rate should be
performed in case of concomitant use of vitamin K dependent factor anticoagulant.
Rifampicin: Rifampicin may decrease the valproate blood levels resulting in a lack of
therapeutic effect. Therefore, valproate dosage adjustment may be necessary when it is co-
administered with rifampicin.
c. Other interactions:
Topiramate: Concomitant administration of valproate and topiramate has been associated with
encephalopathy and/or hyperammonemia. Patients treated with those two drugs should be
carefully monitored for signs and symptoms of hyperammonemic encephalopathy.
Interference with Clinical Laboratory and Other Tests
Epilim is eliminated mainly through the kidneys, partly in the form of ketone bodies. This may give false positives in the urine testing of possible diabetics. There have been reports of altered thyroid function test results associated with sodium valproate. The clinical significance of this is unknown. Effect on Ability to Drive or Operate Machinery
Use of Epilim may provide seizure control such that the patient may be eligible to hold a driving licence. However, patients should be warned of the risk of transient drowsiness, especially in cases of anticonvulsant polytherapy, too high a starting dose, too rapid a dose escalation or association with benzodiazepines. ADVERSE EFFECTS
The following CIOMS frequency rating is used:  1/100 and < 1/10 ( 1% and < 10%)  1/1000 and < 1/100 ( 0.1% and < 1.0%)  1/10,000 and < 1/1000 ( 0.01% and < 0.1%) Skin and subcutaneous tissue disorders: Hypersensitivity and transient and/or dose related
alopecia has been observed commonly. Angiodema and rash is uncommon. Toxic epidermal
necrolysis, Stevens-Johnson syndrome, Drug Rash with Eosinophilia and Systemic Symptoms
(DRESS) syndrome and erythema multiforme have been reported rarely. Caution should be
observed when using the medicine in patients with systemic lupus erythematosus.
Musculoskeletal and connective tissue disorders: Decreased bone mineral density,
osteopenia, osteoporosis and fractures in patients on long-term therapy with valproate have
been uncommon. The mechanism by which valproate affects bone metabolism has not been
identified. Systemic lupus erythematosus is rare.
Endocrine disorders: Hypothyroidism is rare.
Reproductive system and breast disorders: There have been reports of irregular menses
and secondary amenorrhoea and rare cases of breast enlargement and galactorrhoea.
Dysmenorrhoea is common and amenorrhoea is uncommon. There have been rare reports of
male infertility and polycystic ovaries.
Gastrointestinal disorders: Nausea is very common. Upper abdominal pain and diarrhoea are
common and frequently occur at the start of treatment and usually disappear after a few days
without discontinuing treatment. Vomiting, abdominal cramp, upper abdominal pain, anorexia,
increased appetite and diarrhoea are usually transient and rarely require discontinuation of
therapy or limitation of dose. The overall incidence of adverse GI effects are reported to be 9 to
16% in adults and over 22% in children when plain tablets are prescribed. GI side effects may be
minimised by taking the tablets with or after food or by substituting the enteric-coated tablets. As
some of these symptoms may also indicate early stage hepatic dysfunction, patients should be
monitored closely for the appearance of these symptoms. Patients should be instructed to
report such signs to the clinician for investigation should they occur (refer PRECAUTIONS
section).
There have been uncommon reports of pancreatitis, sometimes lethal, occurring in patients
receiving valproic acid or sodium valproate, usually within the first 6 months of therapy. Patients
experiencing acute abdominal pain should have their serum amylase estimated promptly; if
these levels are elevated the medicine should be withdrawn (see PRECAUTIONS).
Blood and lymphatic system disorders: Valproic acid inhibits the second stage of platelet
aggregation. Reversible prolongation of bleeding time, as well as thrombocytopenia, have been
reported but have usually been associated with doses above those recommended (see Check
the Following Before Use). Common cases of thrombocytopaenia and anaemia have been
reported. ncommon cases of leucopenia and pancytopaenia with or without bone marrow
depression have been reported. Isolated cases of decreased blood fibrinogen and prolonged
prothrombin time have been reported.
Spontaneous bruising or bleeding is an indication for withdrawal of medication pending
investigation (see PRECAUTIONS).
Red cell hypoplasia, neutropenia and leucopenia have also been reported. In most cases the blood picture returned to normal when the medicine was discontinued. Bone marrow failure, including pure red cell aplasia, agranulocytosis, anaemia macrocytic and macrocytosis have rarely been reported. Hepatobiliary disorders: Hepatic dysfunction, including hepatic failure resulting in fatalities,
has occurred in patients whose treatment included valproic acid or sodium valproate (see
PRECAUTIONS). Liver injury is common.
Metabolism and nutrition disorders: Hyperammonaemia is rare. This has been reported in
association with valproate therapy and may be present despite normal liver function tests.
Isolated and moderate hyperammonaemia may occur frequently and should not cause treatment
discontinuation.
In patients who develop unexplained lethargy and vomiting or changes in mental status, hyperammonaemic encephalopathy should be considered. In these patients, EEG and ammonia level should be checked and, if ammonia is increased, valproate therapy should be discontinued. Appropriate interventions for treatment of hyperammonaemia should be initiated, and such patients should undergo investigation for underlying urea cycle disorders (see
PRECAUTIONS).
Asymptomatic elevations of ammonia are more common and, when present, require close monitoring of plasma ammonia levels. If the elevation is significant (above 3N) and persists, discontinuation of valproate therapy should be considered. Common cases of hyponatremia have been reported. Syndrome of Inappropriate Secretion of ADH (SIADH) is uncommon. Nervous system disorders: The true incidence of drowsiness and sedation with Epilim is
difficult to assess, as mostly it was administered in combination with other medicines. Epilim,
however, may have an intrinsic sedative action in addition to potentiating sedative effects of
other anticonvulsants (e.g. barbiturates, clonazepam) and CNS depressants, including alcohol.
In monotherapy, sedation occurred early in treatment on rare occasions and is usually transient.
Very common cases of tremor have been reported. Common cases of stupor, somnolence, convulsion, memory impairment, headache, nystagmus and dizziness have been reported. Uncommon cases of ataxia, coma, encephalopathy, lethargy and paresthesia have been reported. Diplopia, depression and hallucinations have occurred rarely and usually in association with other anticonvulsants. Excitement, alertness, hyperactivity and behavioural disorders have been rarely reported, usually in children at the start of treatment. A few cases of stupor and lethargy sometimes leading to transient coma (encephalopathy) have been reported. They were isolated or associated with an increase in the occurrence of convulsions whilst on therapy, and they decreased on withdrawal of treatment or reduction of dosage. These cases mostly occurred during combined therapy (in particular with phenobarbital or topiramate) or after a sudden increase in valproate doses. When using Epilim intravenously, dizziness may occur a few minutes after injection; it disappears spontaneously within a few minutes. Rare cases of reversible dementia associated with reversible cerebral atrophy and cognitive disorder have been reported. Common cases of extrapyramidal disorder which may not be reversible, including reversible parkinsonism has been reported. Psychiatric disorders: Confusional state, aggression, agitation and disturbance in attention are
common. Abnormal behaviour, psychomotor hyperactivity and learning disorder are rare.
Ear and labyrinth disorders: Deafness, either reversible or irreversible, has been reported
commonly.
Immune system disorders: Angioedema, Drug Rash with Eosinophilia and Systemic
Symptoms (DRESS) syndrome and allergic reactions have been observed.
Neoplasms benign, malignant and unspecified (including cysts and polyps):
Myelodysplastic syndrome is rare.
Respiratory, thoracic and mediastinal disorders: Pleural effusion has uncommonly been
reported.
Renal and urinary disorders: Rare cases of enuresis have been reported.
Rare cases of reversible Fanconi’s syndrome associated with valproate therapy have been reported but the mode of action is as yet unclear. Vascular disorders: Haemorrhage is common and the occurrence of vasculitis is uncommon.
Investigations: Coagulation factors decreased, abnormal coagulation tests (such as prolonged
prothrombin time, activated partial thromboplastin time, thrombin time and INR) have rarely been
reported.
General disorders and administration site conditions: Oedema has been reported. Non-
severe peripheral oedema is uncommon. Increase in appetite may occur. Increased weight is
common and since this is a risk factor for polycystic ovary syndrome, it should be carefully
monitored.
In Bipolar Disorder
No new or unexpected adverse events have been reported in clinical trials of Epilim in mania.
The frequencies of adverse events (%) reported on valproate (as divalproex) in the largest
controlled clinical trial described under PHARMACOLOGY (Clinical Trials) are summarised in
Table 2.
Table 2. Adverse events reported on divalproex in the Bowden et al. study (1994)
Adverse event
Body as a whole
Gastrointestinal
Nervous system
Adverse events reported at a frequency: >15% or significantly different between treatment groups, or > 5% or common events to other study (no events significantly more frequent in this study). In this study, there were differences with placebo for vomiting only for divalproex (45% vs 14%), fever was more common for lithium (14%) than for divalproex (1%) and placebo (4%), pain was less common with lithium (3%) than with either divalproex (19%) or placebo (20%). DOSAGE AND ADMINISTRATION
Epilim tablets may be given twice daily. Uncoated tablets may be crushed if necessary. Epilim Syrup and Sugar-Free Liquid should be given in divided doses. Epilim should preferably be taken with or after food: the enteric-coated tablet (lilac) must be swallowed whole, if necessary with a little water: the plain tablet (white, 100 mg) may be taken whole or crushed and swallowed with water (not aerated). Epilim 500 mg enteric-coated is recommended for patients requiring high doses. Where the possibility of dental caries represents a risk through long-term therapy with Epilim Syrup, it may be beneficial to consider Epilim Sugar-Free Liquid. Epilim may take several days to show an initial effect and in some cases may take from 2 to 6 weeks to exhibit its maximum effect. Epilepsy
Monotherapy: Usual requirements are as follows:
Adults: Dosage should start with 600 mg daily increasing by 200 mg/day at three-day intervals
until control is achieved. This is generally within the range 1,000 to 2,000 mg/day, (i.e. 20 to
30 mg/kg/day). Where adequate control is not achieved within this range the dose may be
further increased to 2,500 mg/day.
Children > 20 kg: Initial dosage should be 400 mg/day (irrespective of weight) with spaced
increases until control is achieved; this is usually within the range 20 to 30 mg/kg/day. Where
adequate control is not achieved within this range, the dose may be increased to 35 mg/kg body
weight per day.
Children < 20 kg: 20 mg/kg/day: in severe cases this may be increased but only in patients in
whom plasma valproic acid levels can be monitored. Above 40 mg/kg/day, clinical chemistry
and haematological parameters should be monitored.
General considerations: Optimum dosage is mainly determined by seizure control and routine measurement of plasma levels is unnecessary. However, a method for measurement of plasma levels is available and may be helpful where there is poor control or side effects are suspected. Bipolar Disorder
Initially dosage should start with 600 mg daily in 2 to 3 divided doses. From day 2 the dose should be increased as rapidly as possible to achieve the lowest therapeutic dose which produces the desired clinical effect. Daily doses generally within the range 1,000 to 2,000 mg/day, (i.e. 20 to 30 mg/kg/day). Where adequate control is not achieved within this range the dose may be further increased to 2,500 mg/day. The Bowden et al study (see PHARMACOLOGY, Clinical Trials) provided strong support for
the greater efficacy of serum levels above 45 g/mL (these levels achieved 20% or greater
improvement on both subscales of the Mania Rating Scale). Bowden noted that > 125 g/mL
had greater drug-related adverse events. Between these extremes there does not appear to be
a clear dose-response relationship.
Optimum dosage is mainly determined by control. However, a method for measurement of plasma levels is available and may be helpful where there is poor control or side effects are suspected. Epilepsy and bipolar disorder
Epilim IV may be given by direct slow intravenous injection or by slow intravenous infusion in 0.9% NaCL (normal saline), 5% glucose solution or glucose saline, using a separate intravenous line. The recommended concentration of the intravenous infusion solution is 4 mg/mL, with 8 mg/mL being the maximum concentration. Epilim IV should not be administered at the same time as other intravenous additives via the same IV line. The intravenous solution is suitable for infusion by PVC, polyethylene or glass containers. To reconstitute, inject the solvent provided (4mL) into the vial, allow to dissolve and extract the appropriate dose. Due to displacement of solvent by sodium valproate the concentration of reconstituted sodium valproate is 95mg/mL. Epilim IV should be replaced by oral Epilim therapy as soon as practicable. Each ampoule of Epilim IV is for single dose injection only. To reduce microbiological hazard,
use as soon as practicable after reconstitution. If storage is necessary hold at 2 to 8ºC for not
more than 24 hours. Epilim IV is intended for use in one patient on one occasion only, any
unused portion should be discarded. NEVER ADMINISTER Epilim IV OTHER THAN BY THE
INTRAVENOUS ROUTE (see CONTRAINDICATIONS).
Monotherapy:
Daily dosage requirements vary according to age and body weight. Patients already satisfactorily treated with Epilim may be continued at their current dosage using continuous infusion. For example, a patient stabilised on 25 mg/kg administered daily should be continued with an infusion at the rate of 1 mg/kg/hr. Other patients may be given a slow intravenous injection over 3-5 minutes, usually 400-800 mg depending on body weight (up to 10 mg/kg) followed by continuous infusion of 1-2 mg/kg/hr up to a maximum of 2500 mg/day, according to the patient’s clinical response. The daily requirement for children is usually in the range 20-30 mg/kg/day and method of administration is as above. Where adequate control is not achieved within this range the dose may be increased up to 40 mg/kg/day but only in patients in whom plasma valproic acid levels can be monitored. Above 40 mg/kg/day clinical chemistry and haematological parameters should be monitored. ORAL and IV
Hepatic Impairment: Liver dysfunction, including hepatic failure resulting in fatalities, has
occurred in patients whose treatment included valproic acid or sodium valproate (see
PRECAUTIONS).
Impaired renal function: Lower doses may be required since free drug levels may be high
owing to lowered serum albumin and poor urinary excretion of free drug metabolites (see
PRECAUTIONS). Dosage should be adjusted according to clinical monitoring since monitoring
of plasma concentrations may be misleading. (See Pharmacokinetics).
Use in children and adolescents: The safety and efficacy of sodium valproate for the treatment of manic episodes in bipolar disorder have not been evaluated in patients aged less than 18 years. Use in the elderly: Although the pharmacokinetics of Epilim are modified in the elderly, they
have limited clinical significance and dosage should be determined by seizure control and/or
control of symptoms. The volume of distribution is increased in the elderly and because of
decreased binding to serum albumin, the proportion of free drug is increased. This will affect the
clinical interpretation of plasma valproic acid levels.
Combined therapy: When starting Epilim in patients on other anticonvulsants, these should be
tapered slowly: initiation of Epilim therapy should then be gradual, with target dose being
reached after about 2 weeks. In certain cases it may be necessary to raise the dose by 5 to
10 mg/kg/day when used in combination with anticonvulsants, which induce liver enzyme
activity, e.g. phenytoin, phenobarbitone and carbamazepine. Once known enzyme inducers
have been withdrawn it may be possible to maintain seizure control on a reduced dose of Epilim.
When barbiturates are being administered concomitantly, the dosage of barbiturate should be
reduced if sedation is observed.
OVERDOSAGE
Cases of accidental and suicidal overdosage have been reported. Fatalities are rare. At plasma concentrations of up to 5 or 6 times the maximum therapeutic levels, there are unlikely to be any symptoms other than nausea, vomiting and dizziness. Symptoms of overdosage may include serious CNS depression and impairment of respiration. In cases of overdose, long half-lives up to 30 hours have been reported. Signs of an acute massive overdose usually include coma, with muscular hypotonia, hyporeflexia and miosis, impaired respiratory functions and metabolic acidosis. Symptoms may however be variable and seizures have been reported in the presence of very high plasma levels. Cases of intracranial hypertension related to cerebral oedema have been reported. Deaths have occurred following massive overdose. Hospital management of overdose including assisted ventilation and other supportive measures are recommended. Establish airway and breathing and evaluate circulatory status. Assisted mechanical ventilation may be required in cases of respiratory depression. For ingested medicine, activated charcoal may reduce the absorption of the medicine if given within one or two hours after ingestion. In patients who are not fully conscious or have impaired gag reflex, consideration should be given to administering activated charcoal via nasogastric tube, once the airway is protected. Haemodialysis and haemoperfusion have been used successfully. Intravenous naloxone has also been used sometimes in association with activated charcoal given orally. Provided that adequate supportive treatment is given, full recovery usually occurs. Particular attention should be given to the maintenance of an adequate urinary output. Hepatic and pancreatic function should be monitored. Contact the Poisons Information Centre for advice on management of overdosage. PRESENTATION AND STORAGE CONDITIONS
Crushable Tablets, 100 mg (white, scored): Blister packs of 100 tablets. Store below 30oC. Store in a dry place. Tablets, 200 mg (lilac, enteric-coated): Blister packs of 100 tablets. Store below 30oC. Store in a dry place. Tablets, 500 mg (lilac enteric-coated): Blister packs of 100 tablets. Store below 30oC. Store in a dry place. Syrup, 200 mg/5 mL (red, cherry flavoured): 300 mL amber glass bottle. Store below 25oC. Store away from direct sunlight. Sugar free liquid, 200 mg/5 mL (red, cherry flavoured): 300 mL amber glass bottle. Store below 25oC. Store away from direct sunlight. Epilim tablets are hygroscopic and must be kept in protective foil until taken. Epilim IV Powder for Injection is presented in single packs. Each pack contains one glass vial of 400 mg sodium valproate freeze-dried powder and one glass ampoule containing 4 mL of solvent (Water for Injections). Store in a dry place below 25C For intravenous use, the reconstituted solution should be used as soon as practicable after reconstitution, to reduce microbiological hazard. If storage is necessary hold at 2 to 8ºC for not more than 24 hours and discard any remaining solution. MEDICINE CLASSIFICATION
NAME AND ADDRESS OF THE SPONSOR:
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