SIDE EFFECTS: Nausea, vomiting, dizziness, stomach upset, and abdominal cramps may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if any of these rare but very serious side effects occur: signs of serious infection (such as high fever, severe chills, persistent sore throat), signs of a sudden loss of red blood cells (such as severe tiredness, brown urine, pale lips/nails/skin, fast heartbeat/breathing with usual activities), signs of a certain blood problem (methemoglobinemia, including bluish skin/lips/nails, headache, shortness of breath, lightheadedness, weakness, confusion, chest pain, sudden pounding heartbeat). Get medical help right away if any of these rare but serious side effects occur: fast/irregular heartbeat, severe dizziness, fainting. A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: 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 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. 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 child-bearing 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 not known whether this drug passes into breast milk and the effect on a nursing infant is unknown. The doctor should test your infant for G6PD deficiency before breastfeeding. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: penicillamine, quinacrine, drugs that may cause decreased blood cells (such as trimethoprim, zidovudine, pyrimethamine, azathioprine).

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: extreme drowsiness, seizures, fast/irregular heartbeat.