Use of verapamil as a potential P-glycoprotein inhibitor in a patient with refractory epilepsy

OBJECTIVE: To describe a patient in whom we used adjunctive verapamil therapy was used for its P-glycoprotein inhibitory effects. CASE SUMMARY: Verapamil was added to the antiepileptic drug regimen of a 24-year-old woman with intractable epilepsy. The average time interval between hospitalizations for complex partial status doubled. The addition of verapamil greatly improved overall seizure control and subjective quality of life in this pharmacoresistant patient. DISCUSSION: The overexpression of P-glycoprotein in the central nervous system may be one mechanism of pharmacoresistance in patients with epilepsy. The calcium-channel blocker verapamil is a known inhibitor of P-glycoprotein and may function to block P-glycoprotein-modulated efflux of antiepileptic drugs in the brain, thereby raising the intracellular concentration of antiepileptic drugs and ultimately decreasing seizure burden in patients with refractory epilepsy. CONCLUSIONS: Verapamil may offer pharmacoresistant patients hope of improved seizure control due to its potential P-glycoprotein inhibitory effects.