Introduction: Primaquine is now the only drug available to eradicate Plasmodium vivax malaria. The optimal dose of primaquine to prevent relapses of P. vivax remains under discussion.
Clinical cases: We describe three cases of P. vivax malaria from different geographical areas, in which a tolerance to standard doses of primaquine and, in some cases, to much higher doses has been observed.
Comments: P. vivax tolerance to primaquine is an emerging problem in daily practice. Reassessment of the primaquine dose required to eradicate P. vivax intrahepatic hypnozoites is needed.