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Antihistamine Fights Malaria

Researchers from the Johns Hopkins School of Public Health have found an old drug with a new and important use. They compiled a catalog of several thousand medications already approved for human use. They tested each drug against the parasite that causes malaria, and eventually focused in on Astemizole, an antihistamine and anti-allergy medication.

Team leader David Sullivan says it had an effect on even the most virulent strain of malaria. "We found that the drug and its principle human metabolite, dezmethalastemizole, were active against drug-sensitive human malaria strains, particularly plasmodium falciparum and against drug-resistant [strains] of plasmodium falciparum."

Known as Seldane in the United States, Astemizole has not been used for more than a decade. It was pulled from the market after some people who took the drug for long periods of time developed irregular heart rhythms, especially if they were taking some kinds of antibiotics. "The toxicities were seen with taking the drug for months at a time," Sullivan explains, pointing out, "for malaria treatment, you'd just be taking the drug for a couple of days and not be taking it 30 days in a row for a couple of months in a row for chronic allergies. So the side effects potentially could be less for just shorter drug regimens."

Sullivan says one advantage of his team's approach to looking for new anti-malarials is speed. Since all the drugs in their catalog have already been tested for safety in humans, they could be fast-tracked for approval against malaria. "It opens the potential for us to go directly to testing in humans because there's already a lot of information about Astemizole," he says. "Not to say that it's going to be a perfect drug. In the end we sort of conceive of it as being a backup that possibly could be used in combination with the potent [new medicines called] artimisenins."

The Johns Hopkins team hopes to start testing Astemizole for human malaria treatment some time next year.