Focale Drug Interactions

AEDs (e.g., phenytoin, carbamazepine, valproic acid, phenobarbital, lamotrigine, gabapentin, and primidone): Levetiracetam may not significantly influence the plasma concentrations of these other AEDs, and that the other AEDs may not significantly influence the plasma concentrations of levetiracetam.
Concomitant use of carbamazepine and levetiracetam has been reported to increase carbamazepine-induced toxicity (e.g., nystagmus, nausea, vomiting).
Alcohol: No data on the interaction of levetiracetam with alcohol is available.
Antacids: No data on the influence of antacids on the absorption of levetiracetam is available.
Digoxin: Concomitant use of digoxin did not influence the pharmacokinetics of levetiracetam.
Methotrexate: Concomitant administration of levetiracetam and methotrexate has been reported to decrease methotrexate clearance, resulting in increased/prolonged blood methotrexate concentration to potentially toxic levels. Blood methotrexate and levetiracetam levels should be carefully monitored in patients treated concomitantly with the two drugs.
Laxatives: There have been reports on isolated cases of reduced efficacy of oral levetiracetam when it is concomitantly administered with the osmotic laxative macrogol. Thus, macrogol should not be orally administered for one hour before and for one hour after taking levetiracetam.
Oral Contraceptives (e.g., ethinylestradiol and levonorgestrel): No clinically significant pharmacokinetic interactions were observed. However, pharmacokinetic interaction studies using levetiracetam as adjunctive therapy and covering the recommended dosage range have not been conducted. Therefore, physicians should advise their female patients to be alert to any irregular vaginal bleeding or spotting, and to immediately report to them any occurrences.
Probenecid: Probenecid did not change the pharmacokinetics of levetiracetam when concomitantly used. The effect of levetiracetam on probenecid was not studied.
Warfarin: Concomitant use of warfarin and levetiracetam did not affect the pharmacokinetics of levetiracetam.
Prothrombin time was not affected by levetiracetam.