Primaquine Contraindications: What You Must Know Before Taking It

When you're prescribed primaquine, a blood-stage antimalarial drug used to prevent relapse of Plasmodium vivax and P. ovale infections. It's not just another pill—this drug can cause serious harm if you have certain conditions, and many people don't realize it until it's too late. Primaquine works by killing dormant liver parasites that other malaria drugs miss, but that same power makes it dangerous for some. The biggest red flag? G6PD deficiency, a genetic condition where the body can't protect red blood cells from oxidative stress. If you have this, primaquine can trigger life-threatening hemolytic anemia—your red blood cells literally break apart. Doctors test for this before prescribing, but if you’ve never been tested, or if you’re self-medicating abroad, you’re at risk.

Primaquine also isn’t safe during pregnancy, especially in the first trimester. The drug crosses the placenta and can harm the developing fetus, particularly if the baby inherits G6PD deficiency from the father. Even if you’re not sure about your G6PD status, skipping primaquine while pregnant is the standard advice. It’s also a no-go if you’re breastfeeding—infants with undiagnosed G6PD deficiency can have severe reactions through breast milk. Other red flags? A history of blood disorders, like methemoglobinemia or chronic kidney disease. If your kidneys are struggling, primaquine builds up in your system and increases toxicity. And if you’re taking other meds—like cimetidine or certain antibiotics—your body might not clear primaquine properly, raising your risk of side effects. Some people get nausea or dizziness, but those are mild. The real danger is silent and sudden: dark urine, extreme fatigue, yellow skin, fast heartbeat—signs your red blood cells are being destroyed.

You might think, "I’ve taken it before and felt fine," but G6PD deficiency can be mild and undetected until you’re exposed to a trigger like primaquine. That’s why testing isn’t optional—it’s essential. Even if you’re traveling to a malaria zone and considering buying primaquine online, don’t skip the blood test. This isn’t a drug you can guess your way through. The posts below cover real cases, comparisons with other antimalarials, and what to do if you’ve been exposed to primaquine without knowing your status. You’ll find practical advice from patients and doctors who’ve seen the consequences firsthand. This isn’t theoretical. It’s about avoiding irreversible damage.