PROPHYLACTIC DOXYCYCLINE FOR TRAVELERS DIARRHEA - RESULTS OF A PROSPECTIVE DOUBLE-BLIND-STUDY OF PEACE-CORPS VOLUNTEERS IN MOROCCO

Abstract

A 2nd randomized double-blind study to determine the efficacy of doxycycline, 100 mg daily, for the prevention of travelers'' diarrhea was carried out among 50 Peace Corps Volunteers during their 1st 10 wk in Morocco. The volunteers took doxycycline or placebo for 3 wk and were observed for an additional 7 wk. Eleven of 24 taking the placebo and 2 of 26 taking doxycycline had travelers'' diarrhea during the treatment period (P < 0.01). One week after cessation of the doxycycline persons in that group developed an increase in frequency of travelers'' diarrhea (P < 0.05) so that by 3 wk after the drug was stopped, there were no differences between the groups. Enterotoxigenic Escherichia coli, most of which were sensitive to doxycycline, were the most frequently isolated pathogens during the entire study. This study corroborates the effectiveness of doxycycline prophylaxis for travelers'' diarrhea.