Table 1:

Pharmacokinetics of Antiarrhythmic Drugs

Antiarrhythmic Class	Agent	CYP Substrate	P-gp Substrate	Enzymes/Transporters Inhibited
Class Ia	Quinidine	3A4	Yes	3A4, 2D6, P-gp
	Procainamide	No	No	None known
	Disopyramide	3A4	No	None known
Class Ib	Lidocaine	1A2, 2B6, 2D6	No	1A2
	Mexiletine	2D6, 1A2	No	1A2
Class Ic	Flecainide	2D6	No	2D6
	Propafenone	1A2, 2D6, 3A4	No	2D6
Class II	Propranolol	2D6, 1A2, 2C19	Yes	P-gp, weakly 2D6
	Bisoprolol	3A4 (minor: 2D6)	Possibly	None known
	Metoprolol	2D6	No	None known
	Carvedilol	2D6, 2C9 (minor: 3A4, 1A1, 1A2, 2C19, 2E1)	No	P-gp
Class III	Amiodarone	3A4, 2C8	No	1A2, 2D6, 2C9, 3A4, P-gp
	Dronedarone	3A4	No	3A4, 2D6, P-gp
	Sotalol	No	No	None known
	Ibutilide	No	No	None known
	Dofetilide	Insignificant	No	None known
Class IV	Verapamil	3A4, 3A5, 2C8 (minor: 1A2, 2C9, 2C19, 2D6, 2E1)	Yes	3A4, P-gp
	Diltiazem	3A4, 2C8, 2C9, 2C19	Yes	3A4, possibly 2D6, P-gp

CYP: cytochrome P-450; P-gp: P-glycoprotein.