Tocainide Antacids

ADM INI STERI NG TOCAIN IDE AN D M EXILETIN E Tocainide and mexiletine are administered at 8-hour intervals and with food (or an antacid) to prevent gastrointestinal upset. In addition, administering tocainide with food may offer some protection gainst toxicity because the absoq> tion rate is slowed in the presence of food. 

Raising the pH of the urine (e.g. with some antacids, diuretics or alkaiine saits) can modestiy reduce the loss of tocainide from the body. 

Preliminary findings of a study found that when 5 healthy subjects took 30 mL of an unnamed antacid four times a day for 48 hours before and 58 hours after a single 600-mg dose of tocainide, the urinary pH rose from 5.9 to 6.9, the total clearance of tocainide fell by 28%, the peak serum levels fell by 19% from 4.2 to 3.4 micrograms/mL, the AUC rose by 33% and the half-life was prolonged from 13.2 to 15.4 hours. ... 

Meneilly GP, Scavone JM, Meneilly GS, Wei JY. Tocainide phannacokinetic alterations during antacid-induced urinary alkalinization Clin Pharmacol Iher (1987) 41,178. 

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