Primaquine Side Effects: What You Need to Know Before Taking It

When you take primaquine, an antimalarial drug used to prevent relapse of Plasmodium vivax and P. ovale malaria. It's not like other malaria meds—it targets dormant liver parasites, but that power comes with serious risks. One in ten people who take it could face a dangerous reaction if they have a hidden genetic condition called G6PD deficiency, a common inherited disorder that affects red blood cell stability. This isn’t theoretical—it’s a real, life-threatening risk that doctors test for before prescribing.

Most people don’t know they have G6PD deficiency until they take primaquine. Then, their red blood cells start breaking down fast, causing hemolytic anemia, a condition where the body destroys red blood cells faster than it can replace them. Symptoms include dark urine, extreme tiredness, yellow skin, and shortness of breath. If you’ve ever had a bad reaction to sulfa drugs, fava beans, or naphthalene (mothballs), you might have it. No test? No primaquine. That’s the rule.

Even if you’re not G6PD deficient, other side effects happen. Nausea, stomach cramps, dizziness, and headaches are common. Some people get a blue tint to their skin or lips—a harmless but startling change. Rarely, it can cause serious heart rhythm issues or liver stress. Pregnant women shouldn’t take it unless absolutely necessary, and breastfeeding moms need to be careful too. It’s not a drug you take lightly. Every dose has to be weighed against your personal health history.

Why does this matter now? Because primaquine is still the only drug that can fully clear certain types of malaria from your body. Without it, the infection comes back. But the side effects aren’t just annoying—they can be deadly if ignored. That’s why you’ll see posts here comparing it to alternatives, explaining how to test for G6PD deficiency, and showing real cases where people got it right—or wrong. You’ll find guides on what to watch for after taking it, how to talk to your doctor about risks, and what to do if you feel off. This isn’t just about knowing the side effects. It’s about knowing how to stay safe while using a drug that saves lives when used correctly.