Valex(Sodium Valproate)

Therapeutic Group: Drugs of Nervous System, Antiepileptic

Presentation

Valex 200 tablet: Each tablet contains Sodium Valproate BP 200 mg.

Valex CR 200 tablet: Each controlled release tablet contains Sodium Valproate 200 mg as Sodium Valproate BP 133.2 mg & Valproic Acid BP 58 mg.

Valex CR 300 tablet: Each controlled release tablet contains Sodium Valproate 300 mg as Sodium Valproate BP 199.8 mg & Valproic Acid BP 87 mg.

Valex CR 500 tablet: Each controlled release tablet contains Sodium Valproate 500 mg as Sodium Valproate BP 333 mg & Valproic Acid BP 145 mg.

Valex syrup: Each 5 ml syrup contains Sodium Valproate BP 200 mg.

Valex 500 injection: Each 5 ml injectable solution contains Sodium Valproate BP eqv. to Valproic Acid 500 mg.

Description

Sodium Valproate, the active ingredient of Valex is endowed with anti-epileptic activity against a variety of seizures. The mechanism by which Sodium Valproate exerts its anti-epileptic effects has not been established. However, it has been suggested that its activity is related to increase brain levels of gamma-aminobutyric acid (GABA).

Indications

Sodium Valproate oral is indicated for the treatment of all types of epilepsy, e.g. Partial seizures, Absence seizures (petit mal), Generalized tonic-clonic seizures (grand mal), Myoclonic seizures, Atonic seizures, Mixed seizures that include absence attack, Prophylaxis of febrile convulsion, Prophylaxis of post-traumatic epilepsy. It is also indicated in the treatment of bipolar disorder & prophylaxis of migraine.

Injection: Indicated in epileptic patients for whom oral therapy is temporarily not possible.

Dosage & Administration

Oral: Sodium Valproate tablets may be given once or twice daily and syrup should be given in divided doses.
Epilepsy: Adult-Initially 600 mg daily given in 2 divided doses, preferably after food, increasing by 200 mg/day at 3-day intervals to a maximum of 2.5 g daily in divided doses until control of seizure is achieved. Usual maintenance dose is 1-2 g daily (20-30 mg/kg daily). Children (over 20 kg)- Initially 400 mg daily in divided doses increased until control (usually in the range of 20-30 mg/kg daily); Maximum 35 mg/kg daily. Children (up to 20 kg)- Initially 20 mg/kg daily in divided doses.
Febrile convulsion: 20-30 mg/kg/day in 3 divided doses.
Bipolar disorder: Initially 600 mg daily (20-30 mg/kg/day) in 2-3 divided doses. Maintenance dosage is 1000-2000 mg daily.
Prophylaxis of migraine: 400-600 mg daily, although some may require 1000-1500 mg daily.

Injection: Adults-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 or repeated infusion up to a maximum of 2500 mg/day. For children- Initial: 20-30 mg/kg/day, Maximum: 40 mg/kg/day. It may be given by direct slow intravenous injection or by infusion using compatible diluents e.g. 0.9% Sodium Chloride injection, 5% Dextrose injection.

Side Effects

The most common side effects are anorexia, nausea and vomiting. However, these side effects are minimized with the use of enteric coated tablets. Effects on the CNS include sedation, ataxia and tremor. These symptoms occur infrequently and usually respond to a decrease in doses. Rash, alopecia and stimulation of appetite have been observed occasionally. Sodium Valproate has several effects on hepatic function of which elevation of liver enzymes in plasma is observed in up to 40% of patients and often occurs asymptomatically during the first few months of therapy. Rarely a fulminate hepatitis that may be fatal may develop. Children below 2 years of age with other medical conditions and those being treated with multiple antiepileptic agents are specially prone to suffer from hepatic injury, acute pancreatitis and hyperammonemia have also been frequently associated with the use of Sodium Valproate

Precautions

Liver functions should be monitored before therapy and during first 6 months especially in patients most at risk, No undue potential for bleeding before starting and before major surgery must be ensured, Care should be taken in renal impairment, pregnancy, breast-feeding and systemic lupus erythematosus. Sodium Valproate is partially eliminated in the urine as a ketone metabolite, which may lead to a false interpretation of the urine ketone test. Sudden withdrawal of therapy should be avoided. Sodium Valproate should not be used during pregnancy and in women of childbearing potential.

Use in Pregnancy & Lactation

Sodium Valproate crosses the placenta and in humans, exposure to valproate in the first trimester has been associated with neural tube defects such as anencephaly and spina bifida in newborn. Pregnant women treated with Sodium Valproate should be offered to estimate serum a-fetoprotein. Sodium Valproate is excreted in breast milk. However, breast-feeding by a mother taking Sodium Valproate probably causes no risk to the child.

Drug Interaction

Sodium Valproate appears to act as a non specific inhibitor of drug metabolism. Drugs to which it interacts most significantly are Phenobarbital, Phenytoin, Warfarin, Aspirin etc.

Storage

Do not store above 30°C. Keep away from light and out of the reach of children.

Commercial Pack

Valex 200 tablet: Each box contains 6 blister strips of 10 tablets.
Valex CR 200 tablet: Each box contains 5 blister strips of 10 tablets.
Valex CR 300 tablet: Each box contains 5 blister strips of 10 tablets.
Valex CR 500 tablet: Each box contains 3 blister strips of 10 tablets.
Valex syrup: Each bottle contains 100 ml of Sodium Valprote syrup.
Valex 500 injection: Each box contains 1 blister strip of 5 ampoules.