A Case of Suspected Drug Interaction Between Topiramate and Co-administered Clarithromycin/Pranlukast

Case description: A 4-year-old boy presented with tuberous sclerosis and symptomatic partial epilepsy of the upper right extremity. Topiramate was prescribed for the treatment of epilepsy, and seizure behavior was well controlled. However, the patient experienced a significantly increased seizure frequency immediately after the administration of clarithromycin and pranlukast treatment during topiramate treatment. Topiramate is metabolized by CYP3A4, which is inhibited by clarithromycin and pranlukast. Thus, pharmacokinetic interactions may have occurred. This is the first report of a possible drug interaction between topiramate, clarithromycin, and pranlukast.