Before taking primaquine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: immune system disease (such as lupus, rheumatoid arthritis), blood problems (such as low white blood cell counts, anemia), history of blood problems due to primaquine (such as hemolytic anemia, methemoglobinemia), personal/family history of favism, low levels of certain blood enzymes (glucose-6-phosphate dehydrogenase-G6PD, NADH methemoglobin reductase).

Your doctor may order a blood test to see if you have any enzyme deficiency before starting primaquine.

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Primaquine may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using primaquine, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using primaquine safely.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).

This medication must not be used during pregnancy. It may harm an unborn baby. Women of childbearing age should have a pregnancy test before starting this medication. It is important to prevent pregnancy during and after treatment with primaquine. Men and women must use reliable forms of birth control (such as condoms, birth control pills) during treatment. Men should continue to use birth control for at least 3 months after the end of treatment. Women should continue to use birth control for at least 1 menstrual cycle after the end of treatment. If you become pregnant or think you may be pregnant, tell your doctor right away. While you are pregnant, traveling to an area with malaria puts you and your infant at a much higher risk for death and other problems. The CDC recommends continuing your other malaria treatment (such as chloroquine) throughout pregnancy until delivery to prevent harm to your unborn baby (hemolytic anemia). After delivery, you may finish treatment with primaquine. Discuss the risks and benefits with your doctor.

It is unknown if this drug passes into breast milk. The doctor should test your infant for G6PD deficiency before breastfeeding. Consult your doctor before breastfeeding.