Primaquine

(prim' a kwin)

Other Name(s): Primaquine phosphate

WHY is this medicine prescribed?

Primaquine is used to treat malaria (a serious infection spread by mosquitoes in some parts of the world) and to prevent the disease from coming back. Primaquine is in a class of medications called antimalarials. It works by killing the organisms that cause malaria.

Are there OTHER USES for this medicine?

Primaquine is also sometimes used to treat Pneumocystis jiroveci pneumonia (lung disease caused by fungus). Talk to your doctor about the risks of using this drug for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Primaquine comes as a tablet to take by mouth. It is usually taken once a day for 14 days. Primaquine may be taken with or without food, but taking it with food may help to prevent nausea, vomiting, or other stomach problems that may be caused by the medication. Take primaquine at around the same time every day.

Take primaquine exactly as directed. Do not take more or less of it or take it more often or for a longer period of time than prescribed by your doctor.

Take primaquine until you finish the prescription, even if you feel better. If you stop taking primaquine too soon or skip doses, your infection may not be completely treated.

What SPECIAL PRECAUTIONS should I follow?

Before taking primaquine,

• tell your doctor or pharmacist if you are allergic to this drug, any part of this drug, or any other drugs, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.

• some medications should not be taken with primaquine. Other medications may cause dosingchanges or extra monitoring when taken with primaquine. Make sure you have discussed anymedications you are currently taking or plan to take before starting primaquine with yourdoctor and pharmacist. Before starting, stopping, or changing any medications while takingprimaquine, please get the advice of your doctor or pharmacist.

• tell your doctor if you have glucose-6-phosphate dehydrogenase (G6PD) deficiency (an inherited blood disease) or if you or someone in your family has had a reaction after eating fava beans. Your doctor may tell you not to take primaquine.

• tell your doctor if you have or have ever had a prolonged QT interval (a rare heart rhythm that may cause irregular heartbeat, fainting, or sudden death); a slow, fast, or irregular heartbeat; low levels of potassium or magnesium in your blood; rheumatoid arthritis; lupus erythematosus (a disease that occurs when the body's tissues are attacked by antibodies from its own immune system); methemoglobinemia (a condition with defective red blood cells that are unable to carry oxygen to the tissues in the body); nicotinamide adenine dinucleotide (NADH) deficiency (a genetic condition); or heart, kidney, or liver disease. Also, tell your doctor if you or someone in your family has had hemolytic anemia (a condition with an abnormally low number of red blood cells).

• tell your doctor if you are pregnant or plan to become pregnant or plan to father a child. If you can become pregnant, you may have to take a pregnancy test before starting treatment. You should use birth control to prevent pregnancy during your treatment with primaquine and for at least 2 months after your last dose. Talk to your doctor about methods of birth control that will work for you. If your partner can become pregnant, you should use a condom while taking this medication and for 3 months after your last dose. If you or your partner become pregnant while taking primaquine, call your doctor immediately. Primaquine may harm the fetus.

• tell your doctor if you are breastfeeding or plan to breastfeed.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Primaquine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• vomiting
• heartburn
• abdominal cramps
• rash
• itching

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• unusual tiredness or weakness, dizziness, pale skin, shortness of breath, headache, fast or pounding heartbeat, yellowing of the skin or eyes, dark urine, or pain in the upper right part of the stomach
• grey-bluish color of lips and/or skin, lack of energy, headache, shortness of breath, or confusion or unusual behavior
• fast or irregular heartbeat, fainting, or seizure
• sore throat, fever, cough, or other signs of infection

Primaquine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light and excess heat and moisture (not in the bathroom).

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website https://goo.gl/c4Rm4p for more information.

Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location – one that is up and away and out of their sight and reach. https://www.upandaway.org

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• abdominal cramps
• vomiting
• heartburn
• grey-bluish color of lips and/or skin
• headache
• difficulty falling asleep or staying asleep
• fast or irregular heartbeat
• fainting

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to primaquine.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking primaquine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2025. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: July 15, 2025.