Primaquine

Mechanism-of-action class: Unknown Cellular or Molecular Interaction.

• Primaquine phosphate is indicated for the radical cure (prevention of relapse) of vivax malaria.ICD-10: B54

• Known hypersensitivity reactions to primaquine phosphate, other 8-­aminoquinolones, or to any component in primaquine. Severe glucose-6-phosphate dehydrogenase (G6PD) deficiency (see WARNINGS, Hemolytic Anemia ).contraindicated

Primaquine phosphate tablets are recommended only for the radical cure of vivax malaria, the prevention of relapse in vivax malaria, or following the termination of chloroquine phosphate suppressive therapy in an area where vivax malaria is endemic. Patients suffering from an attack of vivax malaria or having parasitized red blood cells should receive a course of chloroquine phosphate, which quickly destroys the erythrocytic parasites and terminates the paroxysm. Primaquine phosphate tablets should be administered concurrently to eradicate the exoerythrocytic parasites in adults at a dosage of 1 tablet (equivalent to 15 mg base) daily for 14 days. Primaquine phosphate tablets can be taken with or without food. Administration of primaquine phosphate tablets with food may reduce the incidence of gastrointestinal symptoms.

Hemolytic Anemia Hemolytic reactions (moderate to severe) may occur in individuals with G6PD deficiency and in individuals with a family or personal history of favism. Areas of high prevalence of G6PD deficiency are Africa, Southern Europe, Mediterranean region, Middle East, South-East Asia, and Oceania. People from these regions have a greater tendency to develop hemolytic anemia due to a congenital deficiency of erythrocytic G6PD while receiving primaquine and related drugs. Due to the risk of hemolytic anemia in patients with G6PD deficiency, G6PD testing must be performed before using primaquine. Before initiating treatment, obtain baseline hemoglobin and hematocrit. In case of severe anemia, postpone the G6PD test and decision on treatment with primaquine until recovery. Due to the limitations of G6PD tests, physicians need to be aware of residual risk of hemolysis and adequate medical support and follow-up to manage hemolytic risk should be available. This is of particular importance in individuals with a personal or family history of hemolytic anemia. Patients with G6PD Deficiency Primaquine is contraindicated in patients with severe G6PD deficiency (see CONTRAINDICATIONS ). In case of mild to moderate G6PD deficiency, a decision to prescribe primaquine must be based on an assessment of the risks and benefits of using primaquine. If primaquine administration is considered, baseline hematocrit and hemoglobin must be checked before treatment and close hematological monitoring (e.g., at day 3 and 8) is required.

To report SUSPECTED ADVERSE REACTIONS, please call Ingenus Pharmaceuticals, LLC at 1-877-748-1970 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch Gastrointestinal: Nausea, vomiting, epigastric distress, abdominal cramps. Hematologic: Leukopenia, hemolytic anemia, decreased hemoglobin, methemoglobinemia. Hemolytic anemia occurs commonly in patients with G6PD deficiency and may be severe or fatal in patients with severe G6PD deficiency (see WARNINGS ). Methemoglobin levels are usually <10%, but methemoglobinemia may be severe in nicotinamide adenine dinucleotide (NADH) methemoglobin reductase deficient individuals or in patients with other risk factors (see PRECAUTIONS ). Leukopenia was observed in patients with rheumatoid arthritis or lupus erythematosus (see PRECAUTIONS ). Cardiac: Cardiac arrhythmia and QT interval prolongation (see PRECAUTIONS , OVERDOSAGE ). Nervous System: Dizziness. Skin and Soft Tissue: Rash, pruritus.

Metabolism

Following single oral dosing, the C max and AUC of primaquine increase approximately dose-proportionally over a primaquine base dose range of 15 mg to 45 mg (3 times the approved dose). The pharmacokinetic parameters and properties of primaquine and carboxyprimaquine (main circulating metabolite not expected to be active) in patients with P.

Signs and symptoms Symptoms of overdosage of primaquine phosphate include abdominal cramps, vomiting, burning epigastric distress, central nervous system disturbances including headache, insomnia, and cardiovascular disturbances, including cardiac arrhythmia and QT interval prolongation, methemoglobinemia (indicated by cyanosis), moderate leukocytosis or leukopenia, granulocytopenia, and anemia. Acute hemolysis may occur with particular severity in G6PD deficient patients. Management Treatment of overdosage consists of institution of appropriate symptomatic and/or supportive therapy. Consider contacting a poison center or a medical toxicologist for overdosage management recommendations.

• Jan 23, 1952NDANDA008316Sanofi Aventis Us
• Feb 25, 2014ANDAANDA204476Unichem
• Jun 23, 2016ANDAANDA206043Ingenus Pharms Llc

1. 1Methaemoglobinaemia1923%
2. 2Drug Ineffective1114%
3. 3Drug Interaction1012%
4. 4Pyrexia911%
5. 5Cyanosis89.9%
6. 6Chromaturia67.4%
7. 7Dyspnoea67.4%
8. 8Off Label Use67.4%
9. 9Drug Eruption56.2%
10. 10Plasmodium Vivax Infection56.2%
11. 11Headache44.9%
12. 12Hyponatraemia44.9%
13. 13Syncope44.9%
14. 14Decreased Appetite33.7%
15. 15Disorientation33.7%

Recent PubMed references pinned to Primaquine as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Dissemination of EFFORT trial results in Indonesia: a stakeholder meeting report on tafenoquine and primaquine for radical cure of Plasmodium vivax.
  Malaria journal · 2026 · Pasaribu AP, Jimanto V, Ainur F, et al.
  PMID 42204711DOI 10.1186/s12936-026-05948-3
• Differential impact of Tafenoquine and Primaquine on Plasmodium vivax recurrence: the role of CYP2D6 variants.
  Antimicrobial agents and chemotherapy · 2026 · Godinho VKC, Mwangi VI, Morais MC, et al.
  PMID 42037398DOI 10.1128/aac.01797-25
• Computational insights into the diverse mechanisms in cytochrome P450 2D6-mediated primaquine metabolism.
  Physical chemistry chemical physics : PCCP · 2026 · Zhang H, Zheng Q
  PMID 41925050DOI 10.1039/d5cp04994f
• Effectiveness and safety of 7-day high-dose primaquine and single-dose tafenoquine versus 14-day low-dose primaquine in patients with Plasmodium vivax malaria (EFFORT): a multicentre, open-label, randomised, controlled, superiority trial.
  The Lancet. Infectious diseases · 2026 · Degaga TS, Pasaribu AP, Tripura R, et al.
  PMID 41690325DOI 10.1016/S1473-3099(25)00729-7
• Agent-based simulation of seasonal malaria chemoprevention strategy in Southern Tanzania: comparing dihydroartemisinin-piperaquine with or without primaquine.
  Malaria journal · 2026 · Mfala CT, Nyambo DG, Mwaiswelo RO, et al.
  PMID 41689031DOI 10.1186/s12936-026-05821-3
• Pharmacogenetic Profiling of Cytochrome P450 Enzymes in Plasmodium vivax Patients Treated with Chloroquine and Primaquine: Implications for Personalized Malaria Therapy.
  The American journal of tropical medicine and hygiene · 2026 · Phompradit P, Muhamad P, Cheoymang A, et al.
  PMID 41678828DOI 10.4269/ajtmh.25-0612
• As a novel ferroptosis inhibitor, primaquine alleviates I/R-induced retinal neuron death via increasing GSTA1 activity.
  Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2026 · Lu S, Wang L, Wang K, et al.
  PMID 41529513DOI 10.1016/j.biopha.2026.118973
• Suboptimal primaquine adherence in Plasmodium vivax malaria: Evidence from high-burden tribal districts in Odisha.
  Journal of infection and public health · 2026 · K AV, Thiruvengadam K, Sharma R, et al.
  PMID 41505814DOI 10.1016/j.jiph.2025.103123

The 10 most recently updated of 139 ClinicalTrials.gov registrations naming Primaquine as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• FocaL Mass Drug Administration for Vivax Malaria Elimination
  Recruiting · Phase 3 · Interventional · 7,530 enrolled · University of California, San Francisco
  NCT05690841updated 2026-06-09
• Rigorous Assessment of P. Vivax Relapses and Primaquine Efficacy for Radical Cure
  Completed · Phase 4 · Interventional · 160 enrolled · University of Maryland, Baltimore
  NCT04706130updated 2026-06-03
• Targeting High Risk Populations With Enhanced Reactive Focal Mass Drug Administration in Thailand
  Completed · Interventional · 14,977 enrolled · University of California, San Francisco
  NCT05052502updated 2026-04-29
• Targeting High Risk Populations With Enhanced Reactive Case Detection in Southern Lao Peoples Democratic Republic
  Withdrawn · Interventional · 0 enrolled · University of California, San Francisco
  NCT04416945updated 2026-04-29
• Serological Testing and Treatment for Plasmodium Vivax Malaria: a Trial in Ethiopia and Madagascar
  Recruiting · Phase 3 · Interventional · 19,200 enrolled · London School of Hygiene and Tropical Medicine
  NCT06923592updated 2026-03-24
• Radical Cure (RC) With Tafenoquine or Primaquine After Semi-quantitative G6PD Testing: A Feasibility Study in Peru
  Completed · Observational · 187 enrolled · Medicines for Malaria Venture
  NCT05361486updated 2026-03-20
• Postpartum 8-aminoquinoline Breast Milk Study
  Not yet recruiting · Phase 2 · Phase 3 · Interventional · 60 enrolled · Curtin University
  NCT07060404updated 2026-03-18
• Primaquine for Vivax Malaria in G6PD Intermediate and Deficient Cases.
  Recruiting · Phase 4 · Interventional · 100 enrolled · Menzies School of Health Research
  NCT07468513updated 2026-03-12
• An Ultra-short Course of Primaquine for the Radical Cure of Vivax Malaria
  Not yet recruiting · Phase 3 · Interventional · 1,019 enrolled · Menzies School of Health Research
  NCT07468526updated 2026-03-12
• Assessing the Feasibility of Combining Dihydroartemisinin Piperaquine and Primaquine for Malaria Mass Drug Administration in High Endemic Communities in the Eastern Region of Ghana
  Recruiting · Interventional · 9,000 enrolled · Noguchi Memorial Institute for Medical Research
  NCT07389057updated 2026-02-05

CPIC-curated drug–gene pairs for Primaquine. Levels describe the strength of curated evidence and guideline status — never a recommendation to test or to adjust therapy.

• G6PDCPIC AClinPGx 3FDA label: Testing Required
  G6PD

Frequently asked questions

How does Primaquine work?

Mechanism-of-action class: Unknown Cellular or Molecular Interaction.

What is Primaquine used for?

According to FDA labeling, Primaquine carries indications including: Primaquine phosphate is indicated for the radical cure (prevention of relapse) of vivax malaria.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Primaquine?

Primaquine is classified as Aminoquinolines, Antimalarial, Unknown Cellular or Molecular Interaction, Decreased DNA Integrity, Decreased Protein Synthesis.

What are the contraindications for Primaquine?

Primaquine labeling lists contraindications including: Known hypersensitivity reactions to primaquine phosphate, other 8-­aminoquinolones, or to any component in primaquine. Severe glucose-6-phosphate dehydrogenase (G6PD) deficiency (see WARNINGS, Hemolytic Anemia ).. Always consult the full prescribing information and a clinician.