Primaquine is prescribed to prevent relapses of malaria caused by Plasmodium vivax. It also helps to prevent the spread of falciparum malaria. It is not used alone but in combination with other antimalarial drug/drugs for these purposes. It may also be used to prevent malaria in travelers.
Primaquine is also used in combination with clindamycin
for treating pneumocystis pneumonia
(a fungal infection in lungs commonly seen in AIDS patients and patients taking immunity-suppressing drugs).