The disposition of amopyroquin was investigated in 10 healthy volunteers after a single 2-mg/kg (body weight) intramuscular dose of amopyroquin base. Twenty-two Plasmodium falciparum malaria patients were studied after treatment with one of the following regimens of intramuscularly injected amopyroquin base: 3 mg/kg (body weight), 6 mg/kg, or 6 mg/kg followed by 3 mg/kg 24 h later. Parasitemia was cleared at day 7 in one of six, four of seven, and seven of nine patients, respectively. On the basis of this study, a regimen of 12 mg/kg (body weight) administered in two or three injections is suggested.

The chloroquine-resistant clone (50% inhibitory concentration [IC50] = 1,630 nM) was 26 and 3.7 times less susceptible to monodesethylamodiaquine and amopyroquine, respectively, than the chloroquine-susceptible clone (IC50 = 36.5 nM). Chloroquine-resistant isolates (n = 38) were significantly less susceptible to both monodesethylamodiaquine (IC50 = 74.8 nM) and amopyroquine (IC50 = 18.9 nM), as compared with the 24 chloroquine-susceptible isolates (IC50 = 28.2 nM and 16.1 nM, respectively).