Recently, I consulted on malaria prophylaxis for a patient about to begin missionary work in an endemic area of Indonesia. He refused the CDC-recommended regimens, fearing adverse side effects. However, he was willing to use the low-toxicity natural agent artemisinin 500 mg in a single daily dose with food. A very pure form is available as a food supplement. Is this of benefit? Or should I be more insistent that he use doxycycline or quinine derivatives?—RICHARD R. MASON, DO, NMD, Powell, Ohio

Artemisinins are highly potent antimalarial compounds derived from the sweet wormwood plant and have been used as medicinal agents for over 1,500 years. They are active against all forms of Plasmodium and have minimal side effects. Unfortunately, the prophylactic use of these agents is not feasible because of their extremely short half-life: 500 mg of artemisinin has a half-life of approximately two hours. For the least toxicity, your patient would be best off taking atovaquone/proguanil. Doxycycline frequently causes rash with sun exposure, although it could be used with sunscreen and sun avoidance. The malaria in Indonesia is quinine-resistant, so an alternative choice for this patient would be mefloquine.—Corey Casper, MD, MPH (148-8)