Reviewed on 1/18/2022

What Is Primaquine and How Does It Work?

Primaquine is a prescription medication used for preventing the relapse of malaria caused by P. vivax. 

  • Primaquine may available under different brand names.  

What Are Dosages of Primaquine?

Adult and pediatric dosage


  • 26.3mg

Prevention of relapse of P. vivax malaria

Adult dosage

  • 30 mg orally once daily for 14 days


Pediatric dosage

  • 0.5 mg/kg orally once daily (30 mg/day maximum); start 1-2 days prior to travel and continue for 7 days after departure from malaria endemic area

Dosage Considerations – Should be Given as Follows: 

  • See "Dosages."

What Are Side Effects Associated with Using Primaquine?

Common side effects of Primaquine include:

  • nausea, 
  • vomiting, 
  • stomach cramps
  • irregular heartbeats, 
  • rash, and 
  • dizziness

Serious side effects of Primaquine include:

  • hives, 
  • difficult breathing, 
  • swelling in the face or throat, 
  • fever, 
  • dark colored urine, 
  • pale or yellow colored skin,
  • confusion, and
  • weakness

Rare side effects of Primaquine include:

  • none 

This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Primaquine?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

  • Primaquine has severe interactions with the following drug:
    • lefamulin
  • Primaquine has serious interactions with at least 34 other drugs. 
  • Primaquine has moderate interactions with at least 61 other drugs.
  • Primaquine has minor interactions with the following drugs:

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Primaquine?


  • Severe glucose-6-phosphate dehydrogenase (G6PD) deficiency
  • Coadministration with quinacrine in patients who have received quinacrine recently
  • Concurrent administration with other potentially hemolytic drugs or depressants of myeloid elements of the bone marrow
  • Acutely ill patients suffering from systemic disease manifested by tendency to granulocytopenia, such as rheumatoid arthritis and lupus erythematosus

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Primaquine?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Primaquine?”


  • Since anemia, methemoglobinemia, and leukopenia may occur following administration of large doses of primaquine, do not exceed adult dosage of 1 tablet (= 15 mg base) daily for fourteen days; make routine blood examinations (particularly blood cell counts and hemoglobin determinations) during therapy; drug should be discontinued immediately if marked darkening of urine or sudden decrease in hemoglobin concentration or leukocyte count occurs
  • Observe patient for tolerance if primaquine phosphate is prescribed for an individual who has shown a previous idiosyncrasy to primaquine phosphate (as manifested by hemolytic anemia, methemoglobinemia, or leukopenia), an individual with a family or personal history of favism, or an individual with erythrocytic glucose-6-phosphate dehydrogenase (G-6-PD) deficiency or nicotinamide adenine dinucleotide (NADH) methemoglobin reductase deficiency; discontinue therapy immediately if marked darkening of the urine or sudden decrease in hemoglobin concentration or leukocyte count occurs
  • Due to potential for QT interval prolongation, monitor ECG when using primaquine in patients with cardiac disease, long QT syndrome, a history of ventricular arrhythmias, uncorrected hypokalemia and/or hypomagnesemia, or bradycardia (less than 50 bpm), and during concomitant administration with QT interval prolonging agents

Pregnancy and Lactation

  • Contraindicated in pregnant women; even if a pregnant woman is G6PD normal, the fetus may not be; safe usage in pregnancy not established; use during pregnancy should be avoided except when in judgment of the physician benefit outweighs possible hazard
  • Sexually-active females of reproductive potential should have a pregnancy test prior to starting primaquine


  • Advise females of childbearing potential to use effective contraception (methods that result in less than 1% pregnancy rates) when receiving therapy and after stopping treatment until completion of an ongoing ovulatory cycle (e.g., up to next menses)
  • Advise treated males whose partners may become pregnant, to use a condom while on treatment and for 3 months after stopping treatment


  • CDC recommends do not use in nursing women unless breast-fed infant has been determined not to have G6PD deficiency
Medscape. Primaquine.

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