Molecule

Drug Groups

approved

Description

Proguanil is a prophylactic antimalarial drug, which works by stopping the malaria parasite, Plasmodium falciparum and Plasmodium vivax, from reproducing once it is in the red blood cells. It does this by inhibiting the enzyme, dihydrofolate reductase, which is involved in the reproduction of the parasite.

Indication

For the causal prevention and suppression of malaria caused by susceptible strains of P. falciparum and other species of Plasmodium found in some geographical areas of the world.

Pharmacology

Proguanil is a biguanide derivative that is converted to an active metabolite called cycloguanil. It exerts its antimalarial action by inhibiting parasitic dihydrofolate reductase enzyme. It has causal prophylactic and suppressive activity against P. falciparum and cures the acute infection. It is also effective in suppressing the clinical attacks of vivax malaria. However it is slower compared to 4-aminoquinolines.

Affected Organisms

Biotransformation

Variably metabolized in the liver by cytochrome P450 isoenzymes to the active triazine metabolite, cycloguanil. This variable metabolism of proguanil may have profound clinical importance in poor metabolizers such as the Asian and African populations at risk for malaria infection. Prophylaxis with proguanil may not be effective in these persons because they may not achieve adequate therapeutic levels of the active compound, cycloguanil, even after multiple doses.

Absorption

Rapidly and well absorbed in humans following oral doses ranging from 50 to 500 mg.

Half Life

Approximately 20 hours

Protein Binding

Approximately 75%

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