Drug-Drug Interaction Between Colchicine and Verapamil ER

Colchicine is a substrate for both cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (P-gp). Verapamil hydrochloride is a potent inhibitor of cytochrome P450 (CYP) 3A4 and P-gp. This study will evaluate the effect of multiple doses of extended-release verapamil hydrochloride (verapamil HCl ER) on the pharmacokinetic profile of a single 0.6 mg dose of colchicine. A secondary objective is to evaluate the safety and tolerability of this regimen in healthy volunteers. All study subjects will be monitored for adverse events throughout the study period.