Tocainide pharmacokinetics during continuous ambulatory peritoneal dialysis

Tocainide hydrochloride is a class IB antiarrhythmic agent that has a long duration of action and a narrow therapeutic to toxic ratio. Although tocainide resembles lidocaine structurally, it differs in potency, lipophilicity, metabolism and pharmacokinetic profile. Tocainide is almost completely absorbed after oral administration and has a bioavailability approaching 100%. 1 It is both metabolized and excreted unchanged by the kidney. The metabolites do not exert cardioprotective or cardiotoxic effects. 2 In patients with normal renal function, the biologic half-life of tocainide is about 15 hours. 1 However, in patients with end-stage renal disease, the half-life is prolonged to approximately 23 hours. 3 Hemodialysis removes about 25% of tocainide from the body, decreasing the half-life to about 5 hours. 3 Nonrenal elimination of tocainide in end-stage renal disease appears unaffected. 3 The effect of continuous ambulatory peritoneal dialysis (CAPD) on the elimination of tocainide is unknown. This study examined selected tocainide pharmacokinetic variables in patients undergoing routine CAPD.