This drug is used to treat epilepsy in both children and adults. In children it is also indicated for treatment of Lennox-Gastaut syndrome (a disorder that causes seizures and developmental delay). It is now most frequently prescribed for the prevention of migraines. It has been used by psychiatrists to treat bipolar disorder and alcoholism.

The drug is also used to treat Post Traumatic Stress Disorder. Studies suggest that Topiramate is effective against infantile spasms.

Monotherapy in Epilepsy: Topiramate is indicated as initial monotherapy in patients of 10 years of age and older with partial onset or primary generalized tonic-clonic seizures.

Adjunctive Therapyin Epilepsy: Topiramate is indicated as adjunctive therapy for adults and pediatric patients ages 2-16 years with partial onset seizures, or primary generalized tonic-clonic seizures, and in patients 2 years of age and older with seizures associated with Lennox-Gastaut syndrome.

Migraine: Topiramate is indicated for adults for the prophylaxis of migraine headache.

Adjunct anti-epileptic drugs

Topiramate is a sulfamate-substituted monosaccharide, related to fructose. Topiramate is quickly absorbed after oral use. Topiramate enhances GABA-activated chloride channels. In addition, topiramate inhibits excitatory neurotransmission, through actions on kainate and AMPA receptors. Topiramate has a specific effect on GluR5 kainate receptors. It is also an inhibitor of carbonic anhydrase, particularly subtypes II and IV, but this action is weak and unlikely to be related to its anticonvulsant actions, but may account for the bad taste and the development of renal stones seen during treatment. Its possible effect as a mood stabilizer seems to occur before anticonvulsant qualities at lower dosages.

The initial dose normally is low and increased in slow steps.The usual initial dose is 25 to 50 mg daily in 2 single doses. Recommended increments are 25 to 50 mg every 1 or 2 weeks. Common doses for maintenance treatment are 100 to 200 mg daily. The highest dose possible is 1,000 mg daily in divided doses.

Monotherapy Use: The recommended maximum dose for Topiramate monotherapy in adults and children 10 years of age and older is 400 mg/day in two divided doses.

Adjunctive Therapy Use Adults (17 Years of Age and Over): The recommended total daily dose of Topiramate is 400 mg/day in Partial Seizures or Primary Generalized Tonic-Clonic Seizures. Daily doses above 1600 mg have not been studied.

Pediatric Patients (Ages 2 to 16 Years): Partial Seizures or Primary Generalized Tonic-Clonic Seizures The recommended total daily dose of Topiramate tablets as adjunctive therapy for patients with partial seizures or primary generalized tonic-clonic seizures is approximately 5 to 9 mg/kg/day in two divided doses.Titration should begin at 25 mg (or less, based on a range of 1 to 3 mg/kg/day) nightly for the first week. The dosage should then be increased at 1 or 2 week intervals by increments of 1 to 3 mg/kg/day (administered in two divided doses), to achieve optimal clinical response. Dose titration should be guided by clinical outcome.

Topiramate tablets can be taken without regards to meals.

Potential interactions between Topiramate and standard AEDs like Phenytoin, Carbamazepine and Valproic acid were observed during the concomitant treatment with these drugs for antiepileptic patients. Beside these. Concomitant use of Topiramate, a carbonic anhydrase inhibitor, with other carbonic anhydrase inhibitors, e.g., acetazolamide or dichlorphenamide, may create a physiological environment that increases the risk of renal stone formation. Digoxin, CNS depressants, oral contraceptives. Hydrochlorothiazide (HCTZ) may also interact with Topiramate.

Topiramate tablets are contraindicated in patients with a history of hypersensitivity to any component of this product.

The most common side effects include a change in taste and feelings of pins and needles in the head and extremities. Less common side effects include cognitive deficiency (particularly word-finding difficulty); difficulty in understanding, grogginess, lethargy, renal (kidney) stones, vision abnormality, weight loss, breast pain, abdominal pain, intense sweating, menstrual disorder and dry mouth.

Topiramate is pregnancy category C. So it may be given only if clearly needed and after the assessment of risk benefit ratio. It is not known whether Topiramate is excreted through breast milk. So caution should be taken if it is prescribed to a breast feeding mother.

Concomitant administration of Topiramate and valproic acid has been associated with hyperammonemia with or without encephalopathy in patients who have tolerated either drug alone. In patients who develop unexplained lethargy, vomiting, or changes in mental status, hyperammonemic encephalopathy should be considered and an ammonia level should be measured.

Patients with Renal Impairment: In renally impaired subjects (creatinine clearance less than 70 ml/min/1.73 m2), one-half of the usual adult dose is recommended. Such patients will require a longer time to reach steady-state at each dose.

Patients Undergoing Hemodialysis: Topiramate is cleared by hemodialysis at a rate that is 4 to 6 times greater than a normal individual. Accordingly, a prolonged period of dialysis may cause Topiramate concentration to fall below that required to maintain an anti-seizure effect.To avoid rapid drops in Topiramate plasma concentration during hemodialysis, a supplemental dose of Topiramate may be required. The actual adjustment should take into account 1) the duration of dialysis period, 2) the clearance rate of the dialysis system being used, and 3) the effective renal clearance of Topiramate in the patient being dialyzed.

Overdoses of Topiramate includes convulsions, drowsiness, speech disturbance, blurred vision, diplopia, lethargy, abnormal coordination, stupor, hypotension, abdominal pain, agitation, dizziness and depression.The clinical consequences are not severe. Topiramate overdose results in severe metabolic acidosis.

In acute Topiramate overdose, if the ingestion is recent, the stomach should be emptied immediately by lavage or by induction of ernes is. Activated charcoal has been shown to adsorb Topiramate in vitro. Hemodialysis is an effective means of removing Topiramate from the body.

Store at a cool & dry place, protected from light and moisture. Keep out of reach of the children.