Anti-malarial tablets. Blister packs of Malarone and Larium, anti-malarial drugs. Malaria is caused by the parasite Plasmodium sp., which is carried around by mosquitoes (Anopheles sp.) and injected into a person's bloodstream via a mosquito bite. Malarone is a combination drug, each tablet containing 250 milligrams of atovaquone and 100 milligrams of proguanil hydrochloride. The two active ingredients prevent the parasite Plasmodium falciparum, which causes the most serious form of malaria, malignanat malaria, from reproducing in the bloodstream. Larium is a trade name for mefloquine, which is also used to prevent infection by P. falciparum.