Its exact mechanism of action is not known. Strains of P. falciparum and P. vivax resistant to mefloquine have been reported. Cross resistance between mefloquine and halofantrine has been observed.
Total clearance is essentially hepatic.
The drug is excreted mainly in feces and bile. The pharmacokinetics of mefloquine in patients with compromised renal function and compromised hepatic function have not been studied. For the prophylaxis of P. falciparum and P. vivax malaria infections, including prophylaxis of chloroquine-resistant strains of P. falciparum. In case of life-threatening, serious or overwhelming malaria infections due to P. falciparum, patients should be treated with an i.v. antimalarial drug. Following completion of i.v. treatment, mefloquine may be given orally to complete the course of therapy.