By Emma Patten-Hitt

ATLANTA, Mar 08 (Reuters Health) - People with heart problems or who are taking the antimalarial drug mefloquine should be especially careful to avoid taking another antimalarial drug called halofantrine, according to researchers at the Centers for Disease Control and Prevention (CDC).

Taking protective medication before traveling to areas where malaria exists, such as Africa, can ward off the disease. But in the March 9th issue of the CDC's Morbidity and Mortality Weekly Report, researchers describe the case of a US student--a previously healthy 22-year-old man--who collapsed and died suddenly while leading a teenage exchange group in West Africa.

The student, who was already taking mefloquine prescribed in the US to protect against malaria, was diagnosed by a clinic in Togo as having malaria after he developed chills and a fever about a week into his trip. The clinic gave him halofantrine and an antibiotic and he died 2 days later from heart problems that made him susceptible to the drugs' effects, but of which he was unaware.

"It was probably not a correct diagnosis, which compounds the tragedy," Dr. Robert Newman, of the CDC, told Reuters Health. "People who are taking mefloquine and taking it correctly should be well-protected against malaria--so the likelihood that he actually had malaria is vanishingly small," he said.

Halofantrine has been approved for use in the United States, but is only marketed internationally--not in the US. The drug "can cause rare but serious cardiac complications," according to the CDC report.

An autopsy performed in the US showed that the man had previously undiagnosed hypertrophic cardiomyopathy, an enlargement of the heart that can increase the risk of sudden cardiac death. The manufacturer of halofantrine warns that the drug should not be used in combination with mefloquine or in patients with abnormal heart function.

"It's been available for a long time, and this is not the first report of adverse effects associated with its use," Newman said, but adds that he does not know if this is related to the company's decision not to market it here.

"The concern is that many people may not know if they have heart problems," Newman said. "The type of (heart problems) that could get you into trouble are the ones that are usually silent--that's why it's a great concern," he added.

"It's also a concern in those who are taking mefloquine," he said, pointing out that mefloquine is one of the leading medications used to protect against malaria.

"It's really important to go to a physician prior to travel and get good medicine and advice about malaria," Newman advised. He also suggested that to avoid catching malaria, travelers sleep in a well-screened area, preferably under an insecticide-treated mosquito net, and wear protective clothing and insect repellant when going out in evening hours.

Related MEDLINEplus Pages:

• Malaria