Primaquine is an older antimalarial that still matters because it targets the parasite stages that hide in the liver. That means it prevents relapses from Plasmodium vivax and P. ovale — the forms that can come back weeks or months after the first illness. If you're being treated for those malaria types, primaquine is often the drug that finishes the job.
Before you take primaquine, there's one non-negotiable safety step: a G6PD test. People with glucose-6-phosphate dehydrogenase deficiency can get severe hemolytic anemia when exposed to primaquine. A simple blood test tells your provider whether primaquine is safe for you. If the test shows low G6PD activity, your doctor will pick a different plan.
Primaquine can cause side effects that you should watch for. The most serious is hemolysis, which shows up as dark urine, sudden fatigue, shortness of breath, or yellowing of the skin and eyes. More common, milder effects include nausea, stomach pain, and headache. If you notice any unusual tiredness or urine color changes, call your provider and check your blood counts.
Certain people shouldn't use primaquine: pregnant women, because the fetus's G6PD status is unknown; very young infants; and anyone whose G6PD level is low. If you’re breastfeeding and the baby’s G6PD status is unknown, your clinician may avoid primaquine or delay treatment until testing is done. Also tell your prescriber about all medicines you take — primaquine can interact with other drugs and its effectiveness depends partly on liver enzymes like CYP2D6, so genetics or other meds can change how well it works.
If you're traveling to areas with relapsing malaria, ask about primaquine as part of prevention or follow-up treatment. You’ll usually need a prescription and a lab test first, so plan ahead rather than waiting until you’re sick abroad. For people treated for vivax/ovale malaria at home, providers often add primaquine after the acute phase to clear hidden liver parasites and stop relapses.
Keep simple records: the date you started primaquine, any side effects, and results of G6PD testing. Store the medicine as the label says and finish the full course your clinician prescribes. Don’t combine primaquine with another 8-aminoquinoline like tafenoquine unless a specialist directs it — those drugs overlap and need careful planning.
Questions for your prescriber: Do I need a G6PD test? Is primaquine the right choice for my malaria strain? Are there safer alternatives for me? Clear answers to these will keep treatment effective and reduce risk. If you want more detailed guidance about dosing or local availability, check with a travel clinic or your pharmacist — they can give specifics based on where you are and your health history.
