Epimate-50 Drug Interactions

Other Antiepileptic Drugs: Concomitant administration of topiramate on other antiepileptic drugs has no effect on their steady-state plasma concentrations. Addition of topiramate to lamotrigine had no effect on the plasma concentration of lamotrigine at topiramate doses of 100-400 mg/day. Concomitant administration of topiramate and valproic acid has been associated with hyperammonemia with or without encephalopathy in patients who have tolerated either drug alone. Signs and symptoms are abated once discontinuation of either drug.
Phenytoin and Carbamazepine: Phenytoin and Carbamazepine decrease the plasma concentrations of topiramate.
Digoxin: Digoxin and topiramate co-administration may decrease plasma concentrations of digoxin. Monitoring of serum digoxin is recommended.
CNS Depressants: Concomitant administration of topiramate and other CNS depressants is not recommended because of potential to topiramate to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse events.
Oral Contraceptives: Topiramate increased plasma clearance of the estrogenic component significantly.
Carbonic Anhydrase Inhibitors: Concomitant use of topiramate, a weak 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, and should therefore be avoided.
Lithium: Lithium exposure is reduced during concomitant administration with topiramate at a dose of 200 mg/day. In patients with bipolar disorder, the pharmacokinetics of lithium were unaffected during treatment with topiramate, however an increase in Lithium exposure was observed following topiramate doses of up to 600 mg/day. Monitor Lithium levels when co-administered with topiramate.
Risperidone: When administered concomitantly with topiramate, there was a reduction in the systemic exposure of risperidone.
Metformin: An increase in the plasma concentration of metformin is observed during concomitant administration with topiramate.
Hydrochlorothiazide: Study indicates that co-administration of HCTZ and topiramate increases the concentration of topiramate.
Pioglitazone/Glyburide: A decrease in the concentration of pioglitazone was observed during treatment with topiramate. Systemic exposure of glyburide was also reduced during treatment with topiramate. Careful monitoring of patients for adequate control of their diabetic disease state is advised.