The effect of activated dimethicone and a proprietary antacid preparation containing this agent on the absorption of phenytoin.
1 The bioavailabilty of phenytoin sodium (Epanutin both alone and in combination with activated dimethicone and Asilone (a proprietary antacid preparation containing activated dimethicone) was examined in six healthy male volunteers. 2 The bioavailability of phenytoin when given concomitantly with Asilone was decreased in five of six volunteer subjects (by greater than 30% in three subjects) although this decrease was not shown to be statistically significant. 3 Dimethicone, which has been shown to decrease phenytoin absorption in vitro did not affect phenytoin bioavailability in vivo. 4 It is recommended that when treating patients stabilised on phenytoin one should exercise caution with concomitant phenytoin and antacid therapy to guard against possible changed drug absorption.
D000536:Aluminum Hydroxide / Q000494:pharmacology; D000863:Antacids / Q000494:pharmacology*; D001682:Biological Availability; D004129:Dimethylpolysiloxanes; D004338:Drug Combinations / Q000494:pharmacology; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D008277:Magnesium Oxide / Q000494:pharmacology; D008297:Male; D010672:Phenytoin / Q000378:metabolism*; D012828:Silicones / Q000494:pharmacology*; D012841:Simethicone / Q000494:pharmacology*; D013997:Time Factors
D000863:Antacids; D004129:Dimethylpolysiloxanes; D004338:Drug Combinations; D012828:Silicones; C023473:aluminium hydroxide, magnesium oxide, simeticone drug combination; D008277:Magnesium Oxide; D000536:Aluminum Hydroxide; D010672:Phenytoin; D012841:Simethicone