Tocainide pharmacokinetics

North DS, Mattern AL, Kapil RP, Lalonde RL. The effect of histamine-2 receptor antagonists on tocainide pharmacokinetics. J Clin Pharmacol 1988 28(7) 640-3. 

The first report [138] on the stereoselective pharmacokinetics of tocainide measured plasma concentrations of tocainide enantiomers obtained occasionally from seven patients with life-threatening ventricular arrhythmia over a three-year period. Although large intra- and inter-individual variability was present, the plasma concentrations of the S enantiomer were always higher than those of R-tocainide [138]. Subsequent reports investigated the full pharmacokinetics of tocainide after the IV administration of the racemate to healthy volunteers [127,139] and anephric patients [127] and also after the oral administration of the individual enantiomers in healthy subjects [117] (Table 15). After the IV administration of the racemate, there is no stereoselectivity in the volume of distribution of the... 

Table 15 Stereoselective Pharmacokinetics (MeaniSD) of Tocainide After the Administration of the Individual Enantiomers (R or S) or the Racemate (RS)... 

In a preliminary report of a study, 4 days of treatment with cimetidine [dose not stated] in 11 healthy subjects had a small effect on the pharmacokinetics of tocainide 500 mg given intravenously over 15 minutes, whieh was not considered elinieally important. In another study, cimetidine 300 mg four times daily for 2 days reduced the AUC of a single 400-mg oral dose of toeainide in 7 healthy subjects by about one-third. The peak... 

Phenobarbital does not appear to alter the pharmacokinetics of tocainide. 

Serum theophylline levels are increased by mexiletine and toxicity may occur. Tocainide has only a small and probably clinically unimportant effect on theophylline pharmacokinetics. 

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