The safety and tolerance of atovaquone/proguanil for the long-term prophylaxis of plasmodium falciparum malaria in non-immune travelers and expatriates [corrected].

BACKGROUND

In Europe, atovaquone/proguanil (A/P) is only licensed for malaria prophylaxis for 28 days of travel. Data on the long-term safety and tolerance in nonimmune travelers are scarce.

METHODS

We initiated a prospective observational study on ailments reported by travelers using A/P on a long-term basis. Ailments were recorded on a regular questionnaire. Travelers rated their ailments as (1) mild, not interfering with their daily activities; (2) moderate, causing interference with daily activities; or (3) severe, resulting in a visit to a doctor or clinic.

RESULTS

One hundred sixty-nine subjects used A/P for a total of 2.974 weeks. One hundred fifty-three (90.5%) traveled to malaria-endemic regions in Africa. Seventy-five (44%) travelers, who used A/P for 1.140 weeks, reported no ailments. Ninety-four (56%) subjects who used A/P for 1.834 weeks reported a total of 363 ailments. Diarrhea was the most common ailment (13.5%; graded as mild in 7.2%, moderate in 4.7%, severe in 1.7%). Further complaints were headache (7.4%), malaise (6.1%), insomnia (5.2%), abdominal pain (5.0%), nausea (5.0%), and oral ulcers (4.1%). Four (2.4%) subjects discontinued prophylaxis due to complaints. No patient was admitted. Five (3.0%) cases of malaria were reported.

CONCLUSIONS

In our observational study encompassing more than 57 person-years of follow-up, A/P was tolerated well when taken longer than the current recommendation of 28 days of travel. Treatment-limiting ailments resulting in discontinuation of chemoprophylaxis were observed in 4 of 169 (2.4%) participants, whereas none of them was admitted. There were five (3.0%) cases of self-reported malaria. These observations suggest that A/P is also a safe and efficacious drug for the long-term chemoprophylaxis of falciparum malaria.