ICD-10 Specific code B50: Plasmodium falciparum malaria

Artemether/lumefantrine fixed-dose combination comprises a fixed ratio of 1:6 parts of artemether and lumefantrine, respectively. The site of antiparasitic action of both components is the food vacuole of the malarial parasite, where they are thought to interfere with the conversion of haem, a toxic intermediate produced during haemoglobin breakdown, to the nontoxic haemozoin, malaria pigment. Both artemether and lumefantrine have a secondary action involving inhibition of nucleic acid and protein synthesis within the malarial parasite.

Artemisinin is used in the treatment of malaria due to species Plasmodium.

Artenimol is able to reach high concentrations within the parasitized erythrocytes. Its endoperoxide bridge is thought to be essential for its antimalarial activity, causing free-radical damage to parasite membrane systems. The exact mechanism of action of piperaquine is unknown, but it likely mirrors that of chloroquine, a close structural analogue. Piperaquine is a bisquinoline, and this class has shown good antimalarial activity against chloroquineresistant Plasmodium strains in vitro.

Artesunate is a semi-synthetic artemisinin derivative, indicated for the initial treatment of severe malaria in adults and children. The antimalarial mechanism of action of artesunate is generally thought to depend upon activation involving iron-mediated cleavage of the endoperoxide bridge of DHA to generate an unstable organic free radical followed by alkylation, where the free radical binds to malarial proteins leading to destruction of parasite membranes.

Mefloquine acts on and destroys the asexual intraerythocytic forms of the human malaria parasites: Plasmodium falciparum, P. vivax. P. malariae and P. ovale. It is effective in the treatment and prophylaxis of malaria.

Minocycline is a semi-synthetic derivative of tetracycline. Minocycline inhibits protein synthesis in susceptible bacteria. In common with other tetracyclines it is primarily bacteriostatic and has a similar spectrum of activity to other tetracyclines.

Proguanil is an antimalarial drug and dihydrofolate reductase inhibitor. It acts like the other antifolate antimalarials by interfering with the folic-folinic acid systems and thus exerts its effect mainly at the time the nucleus is dividing. Proguanil is effective against the exoerythrocytic forms of some strains of plasmodium falciparum but it has little or no activity against the exoerythrocytic forms of p. Vivax.

Atovaquone and proguanil interfere with two different pathways involved in the biosynthesis of pyrimidines required for nucleic acid replication. The mechanism of action of atovaquone against P. falciparum is via inhibition of mitochondrial electron transport, and collapse of mitochondrial membrane potential. One mechanism of action of proguanil, via its metabolite cycloguanil, is inhibition of dihydrofolate reductase, which disrupts deoxythymidylate synthesis. Proguanil also has antimalarial and is able to potentiate the ability of atovaquone to collapse mitochondrial membrane potential in malaria parasites. This latter mechanism may explain the synergy seen when atovaquone and proguanil are used in combination.

Quinine is a cinchona alkaloid and a 4-methanolquinoline antimalarial agent which is a rapidly acting blood schizontocide with activity against Plasmodium falciparum, P vivax, P ovale and P malariae. It is active against the gametocytes of P malariae and P vivax, but not against mature gametocytes of P falciparum.