Indications of Valex CR 500 mg
Soduim Valproate & Valproic Acid 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.
Composition
200 tablet: Each enteric coated controlled release tablet contains Sodium Valproate BP 133.2 mg & Valproic acid BP 58 mg equivalent to Sodium Valproate 200 mg.300 tablet: Each enteric coated controlled release tablet contains Sodium Valproate BP 199.8 mg & Valproic acid BP 87 mg equivalent to Sodium Valproate 300 mg.500 tablet: Each enteric coated controlled release tablet contains Sodium Valproate BP 333 mg & Valproic acid BP 145 mg equivalent to Sodium Valproate 500 mg.
Theropeutic Class
Primary anti-epileptic drugs
Pharmacology
Valproate is a generic term used to describe valproic acid, its salts and derivatives. It is available in various forms including the sodium salts (valproate semisodium and sodium valproate), the amide derivative (valpromide), or as valproic acid. Valproate is a carboxylic acid anticonvulsant. It has been suggested that its antiepileptic activity is related to increased brain levels of γ-aminobutyric acid (GABA).
Dosage & Administration of Valex CR 500 mg
Soduim Valproate & Valproic Acid is a prolong release formulation of sodium Valproate, thus Soduim Valproate & Valproic Acid may be given once or twice daily.Epilepsy:
Adults: 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: Initially 20 mg/kg daily in divided doses, may be increased (up to 20 kg) provided plasma concentrations monitored (above 40 mg/kg daily also monitor clinical chemistry and hematological parameters).
Children: Initially 400 mg daily in divided doses increased until control (0ver 20 kg) (usually in the range of 20-30 mg/kg daily); Maximum 35 mg/kg daily. Febrile convulsion 20-30 mg/kg/day in 3 divided doses.
Bipolar disorder: Initially 20-30 mg/kg/day in 2-3 divided doses; adjust dosage in 3-5 days. Maintenance dosage is 1000-2000 mg/day. Prophylaxis of migraine 300 mg twice daily, although some may require 1000 mg daily.
Interaction of Valex CR 500 mg
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.
Contraindications
Sodium Valproate is contraindicated to patients who have known hypersensitivity to the drug and liver dysfunction. Care should be exercised when prescribing Sodium Valproate in women of child bearing age.
Side Effects of Valex CR 500 mg
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.
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 Soduim Valproate & Valproic Acid should be offered to estimate serum a-fetoprotein. This is excreted in breast milk. However, breast-feeding by a mother taking Soduim Valproate & Valproic Acid probably causes no risk to the child.
Precautions & Warnings
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.
Storage Conditions
Store in a cool and dry place, below 30° C and keep away from light.