Each film-coated tablet contains: Topiramate 50 mg.
Pharmacology: Pharmacokinetics: Topiramate is readily absorbed after oral doses, with peak plasma concentrations achieved after 2 hours. Bioavailability is not affected by the presence of food. Protein binding is about 9 to 17%. The volume of distribution in women is approximately half that in men. Topiramate crosses placental barrier and is distributed in breast milk.
In healthy subjects topiramate is not extensively metabolized; however, up to 50% of a dose may undergo metabolism in the liver in patients receiving enzyme-inducing drug concomitantly. It is eliminated chiefly in urine; as unchanged drug and metabolites; mean plasma elimination half-life is about 21 hours. Steady-state concentrations are achieved after 4 to 8 days in patients with normal renal function. Clearance is decreased in patients with impaired renal or hepatic function, and steady- state plasma concentrations may not be achieved for 10 to 15 days in the former. Children exhibit a higher clearance and shorter elimination half-life than adults.
The pharmacokinetics of topiramate may be affected by concurrent administration of other antiepileptics.
Monotherapy in adults and children with newly diagnosed epilepsy. Adjunctive therapy in adults and children under 2 years for refractory partial seizures with or without secondary generalization, seizures associated with Lennox-Gastaut Syndrome and primary generalized tonic-clonic seizures.
Also used for the treatment and prophylaxis of migraine headache in adults.
Epilepsy: Adult: 25 mg once daily by mouth for one week increased thereafter by increments of 25 to 50 mg at intervals of one to two weeks. Daily dose of more than 25 mg should be taken in 2 divided doses.
Adjunctive Therapy: The usual dose for adjunctive therapy is 200 to 400 mg, although some patients may require up to 800 mg daily.
Monotherapy: Usual ranges range from 100 mg to a maximum of 400 mg daily.
Children: Adjunctive Therapy: Children aged 2 to 16 years is 25 mg nightly for the first week, increased at intervals of one to two weeks by increments of 1 to 3 mg/kg/day. The recommended dose thereafter is about 5 to 9 mg/kg/day given in 2 divided doses, though up to 30 mg/kg/day may be given.
Monotherapy: Children aged 6 years and over may be started on 0.5 to 1 mg /kg at night for the first week, increased at intervals of one to two weeks by increments of 0.5 to 1 mg/kg/day. The usual dose is 3 to 6 mg/kg/day in 2 divided doses, although higher doses have been tolerated.
Migraine: Adult: 25 mg per day administered nightly for the first week and increased thereafter by increments of 25 mg. Dosage of more than 25 mg should be taken in 2 divided doses. Usual dose is 100 mg. Dose and titration should be guided by clinical outcome.
Administration in Patients with Renal Impairment: In renally impaired patients (creatinine clearance less than 70 mL/min/1.73 m2), one half of the adult dose is recommended.
Patients Undergoing Hemodialysis: Topiramate is cleared by hemodialysis, a prolonged period of dialysis may cause topiramate concentration to fall below that required to maintain an anti-seizure effect. Thus, in patients undergoing hemodialysis a supplemental dose equal to about one-half of the daily dose should be given in divided doses (at the start and finish of the procedure).
Topiramate tablets may be taken with or without food. Swallow whole, do not chew or crush.
Topiramate is contraindicated in patients with a history of hypersensitivity to any component of this product.
There have been rare reports of acute myopia with secondary angle-closure glaucoma in adults and children receiving topiramate. Symptoms include decreased visual acuity and ocular pain which generally appear within one month of starting treatment; hyperaemia and raised intra-ocular pressure may be present with or without mydriasis. Choroidal effusions resulting in anterior displacement of lens and iris have been reported. Appropriate measures to reduce intra-ocular pressure should be taken, and discontinuation of topiramate as rapidly as possible to reverse the symptoms. Elevated intra-ocular pressure of any etiology, if left untreated, can lead to serious sequelae including permanent vision loss.
Decreased sweating and hyperthermia have been reported in patients given topiramate. Children appeared to be at an increased risk in developing these adverse reactions and should be monitored closely for such effects especially during warm or hot weather. Caution was also advised when topiramate was given with other drugs known to cause similar effects (eg. Carbonic anhydrase inhibitors and antimuscarinics).
Metabolic acidosis has been associated with topiramate treatment. Generally, the decreases in serum bicarbonate are mild to moderate and occur as soon after starting topiramate. Clinical signs such as hyperventilation may develop. Baseline and periodic serum bicarbonate levels should be monitored during topiramate treatment. If metabolic acidosis develops or persists, it may be necessary to reduce the dose or discontinue topiramate although, in some cases, correcting the acidosis with alkali therapy may be appropriate.
Topiramate may cause serious adverse fetal effects. Topiramate should be used during pregnancy only if the potential benefit outweighs the potential risk of the fetus.
As with other antiepileptics, withdrawal of topiramate therapy or transition to or from another type of antiepileptic therapy should be made gradually to avoid precipitating an increase in the frequency of seizures.
Topiramate should be used with caution in patients with renal or hepatic impairment. Adequate hydration is recommended to reduce the risk of developing renal calculi, especially in predisposed patients.
There is an increased risk for the development of cleft lip and/or cleft palate (oral clefts) in infants born to women treated with topiramate during pregnancy.
Adverse effects associated with topiramate therapy include ataxia, impaired concentrations, confusion, dizziness, fatigue, paraesthesia, drowsiness, and difficulties with memory or cognition. Agitation, anxiety, nervousness, emotional lability (with mood disorders), and depression may also occur. Other reported adverse effects include abdominal pain, anorexia, asthenia, diplopia, leucopenia, nausea, nystagmus, insomnia, psychomotor retardation, impaired speech, altered taste, visual disturbances, and weight loss. The risk of developing renal calculi is increased, especially in predisposed patients. Reduced sweating with hyperthermia has occurred particularly in children. Rare cases of myopia with secondary angle-closure glaucoma have been reported.
Phenytoin and Carbamazepine: both decreased the plasma concentration to topiramate.
CNS Depressants: Because of potential to topiramate to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse events, topiramate should be used with extreme caution if used in combination with alcohol and other CNS depressants.
Oral Contraceptives: Topiramate increased plasma clearance of the estrogenic component significantly.
Others: Concomitant use of topiramate, a weak carbonic anhydrase inhibitor, with other carbonic anhydrase inhibitors, e.g. Acetazolamide or dichlorophenamide, may create a physiological environment that increases the risk of renal stone formation, and should therefore be avoided.
Store at temperatures not exceeding 25°C.
N03AX11 - topiramate ; Belongs to the class of other antiepileptics.
Epimate-50 FC tab 50 mg
100's (P5,510/pack)
Sign Out
