Although ampicillin modestly increases plasma levels of mefloquine and reduces its half-life, these effects are probably notclinically relevant.
Clinical evidence,mechanism, importance and management
In a study,8 healthy subjects were given ampicillin 250mg four times daily for 5 days, with a single 750mg dose of mefloquine on day 2. The maximum plasma level and 5-day AUC of mefloquine were increased by 34 % and 49%, respectively, although AUC0–:6.2pt; font-weight:normal; color:#000000″>∞ was not significantly increased. The half-life and volume of distribution of mefloquine were reduced from 17.7 to 15.3 days and by 27%, respectively, by ampicillin. No increase in adverse events was seen. The effects may be due to an increase in mefloquine bioavailability and a reduction in its enterohepatic recycling (See reference number 1). The clinical relevance of these changes is uncertain, but au-
Anthelmintics,Antifungals and Antiprotozoals 231
thors consider that changes in elimination are unlikely to be clinically significant, since these occur after resolution of infection (See reference number 1).
1. Karbwang J,Na Bangchang K, Back DJ, Bunnag D. Effect of ampicillin on mefloquine pharmacokinetics in Thai males. Eur J Clin Pharmacol (1991) 40, 631–3.