Pharmacokinetics of azithromycin and the combination of ivermectin and albendazole when administered alone and concurrently in healthy volunteers.

Azithromycin is a critical component of an integrated disease elimination program against trachoma. This study was conducted to evaluate whether azithromycin has a pharmacokinetic interaction with the combination of ivermectin and albendazole. Eighteen healthy volunteers were administered single doses of azithromycin, ivermectin/albendazole, and the combination of the three agents in random, crossover fashion. To assess the presence of interactions, test (combination) and reference (single dose) data were compared using an estimation approach. Compared with reference phases, the geometric mean values for the combination arm's azithromycin AUC(0-t) and C(max) were increased approximately 13% and 20%, respectively, albendazole AUC(0-t) decreased by approximately 3% and C(max) increased approximately 3%, and ivermectin AUC(0-t) and C(max) were increased 31% and 27%, respectively. Albendazole sulfoxide AUC(0-t) and C(max) were decreased approximately 16% and 14%, respectively. All treatments were well tolerated. The interactions for azithromycin and albendazole were minimal although the increase in ivermectin exposure requires further study.