Primaquine: What It Is, How It Works, and What You Need to Know

When you’re fighting malaria, not all drugs do the same job. Primaquine, a synthetic antimalarial drug used to kill dormant liver stages of the parasite and prevent relapse. Also known as primaquine phosphate, it’s one of the few medicines that can stop malaria from returning weeks or months after the initial infection. Unlike drugs that only clear the blood-stage parasites, primaquine targets the hidden reservoirs in the liver—making it essential for a true radical cure.

It’s often paired with other antimalarials like chloroquine or artemisinin-based combos. While chloroquine clears the active infection, primaquine cleans up what’s left behind. This combo is especially critical in areas where Plasmodium vivax, a type of malaria parasite that can lie dormant in the liver for months is common. Without primaquine, people can get sick again even after they feel fine. It’s also used to block transmission by killing the sexual stages of the parasite in the blood, which mosquitoes pick up.

But it’s not for everyone. People with G6PD deficiency, a genetic condition that affects red blood cell stability can have serious side effects from primaquine, including dangerous anemia. That’s why testing for this condition is standard before prescribing it. Pregnant women, newborns, and people with certain blood disorders are usually advised against it. Still, for millions in malaria-endemic regions, it’s the only way to break the cycle of recurring illness.

You’ll find detailed comparisons in the posts below—like how primaquine stacks up against other antimalarials, who should avoid it, what doses are safe, and how it fits into real-world treatment plans. Some guides dive into its role in elimination programs, others into side effects you won’t find on the label. Whether you’re a patient, caregiver, or just trying to understand why this old drug still matters, these posts give you the straight facts—not marketing, not fluff, just what works and what doesn’t.