Failure of Doxycycline as a Causal Prophylactic Agent against Plasmodium falciparum Malaria in Healthy Nonimmune Volunteers
WALTER REED ARMY INST OF RESEARCH WASHINGTON DC
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To determine whether doxycycline, 100 mg administered as a single daily oral dose, is effective as a causal prophylactic agent, an agent active against the pre-erythrocytic liver stage of Plasmodium falciparum malaria parasites, in healthy nonimmune persons. If effective, the recommendation by the Centers for Disease Control and Prevention CDC that doxycycline be continued for 4 weeks after returning from malaria endemic areas could be shortened to 1 week. Each participant received doxycycline, 100 mg, or placebo in a single daily oral dose starting 3 days before exposure to P. falciparum-infected mosquitoes and ending 6 days after exposure. Six of 6 participants on doxycycline in the first group and 2 of 6 in the second group were protected from malaria. No differences were found between protected and nonprotected participants in the doxycycline elimination half-life, the steady-state minimum doxycycline plasma concentration, the steady-state average plasma concentration, or other pharmacokinetic parameter estimates.
- Anatomy and Physiology