Primaquine


Generic Medicine Info
Indications and Dosage
Oral
Radical cure of ovale malaria, Radical cure of vivax malaria
Adult: 15 mg or 30 mg once daily for 14 days. A course of treatment with a blood schizontocide (e.g. chloroquine) is usually given 1st to kill any erythrocytic parasites and may be administered with or followed by primaquine. Treatment guidelines may vary among countries or individual products. Refer to local treatment guidelines or specific product information.
Child: 0.25-0.3 mg/kg daily for 14 days. Treatment guidelines may vary among countries or individual products. Refer to local treatment guidelines or specific product information.
Special Patient Group
Patients with mild to moderate G6PD deficiency: May consider 45 mg once weekly for 8 weeks with close monitoring for haemolysis.
Administration
Should be taken with food. Take w/ meals to avoid GI discomfort.
Contraindications
Acutely ill patients with systemic disease manifested by a tendency to develop granulocytopenia (e.g. SLE, rheumatoid arthritis); severe G6PD deficiency. Pregnancy. Concomitant use with other drugs causing haemolytic anaemia or myeloid bone marrow suppression; concomitant use with or recent use of mepacrine.
Special Precautions
Patient with family or personal history of favism, haemolytic anaemia, or nicotinamide adenine dinucleotide (NADH) methaemoglobin reductase deficiency; mild to moderate G6PD deficiency or unknown G6PD status (when testing is unavailable); cardiac disease, long QT syndrome, bradycardia (<50 bpm), uncorrected hypokalaemia and/or hypomagnesaemia, history of ventricular arrhythmias; previous idiosyncratic reaction to primaquine. Children. Lactation.
Adverse Reactions
Significant: Moderate to severe haemolytic reactions (particularly in patients with G6PD deficiency and those with family or personal history of favism), methaemoglobinaemia (in patients with NADH methaemoglobin reductase deficiency), leucopenia, anaemia, QT interval prolongation, cardiac arrhythmia.
Eye disorders: Visual disturbances.
Gastrointestinal disorders: Nausea, epigastric distress, vomiting, abdominal cramps.
Nervous system disorders: Headache, dizziness.
Skin and subcutaneous tissue disorders: Rash, pruritus.
Monitoring Parameters
Screen for G6PD deficiency before starting treatment. Obtain CBC (in G6PD normal patients), glucose, electrolytes, and visual colour check of urine periodically. If haemolysis is suspected, obtain haptoglobin, peripheral smear, CBC, and urinalysis dipstick for occult blood prior to starting treatment. In patients with mild to moderate G6PD deficiency or unknown G6PD status (when testing is unavailable), obtain haematocrit and Hb at baseline and monitor CBC periodically (e.g. at Day 3 and 8). Monitor ECG in patients at risk for QT prolongation. Assess for signs of haemolytic anaemia and other haematologic effects. Perform pregnancy test in sexually active females prior to treatment.
Overdosage
Symptoms: Vomiting, abdominal cramps, burning epigastric distress, CNS disturbances, CV disturbances including cardiac arrhythmia and QT interval prolongation, methaemoglobinaemia, cyanosis, anaemia, moderate leucocytosis or leucopenia; granulocytopenia and acute haemolytic anaemia in sensitive patients. Management: Supportive and symptomatic treatment. May consider administering activated charcoal within 1-2 hours after ingestion. Ascorbic acid may be given at a dose of 200 mg tid to treat methaemoglobinaemia after withdrawing primaquine.
Drug Interactions
May enhance the QTc-prolonging effect of QT-prolonging agents.
Potentially Fatal: May increase leucopenic effect with bone marrow depressants. Increased risk of toxic side effects with other haemolytic drugs. Mepacrine may enhance the toxicity of primaquine.
Action
Description:
Mechanism of Action: Primaquine is an 8-aminoquinoline antimalarial which is active against exoerythrocytic stages of Plasmodium vivax and Plasmodium ovale, primary exoerythrocytic stages of Plasmodium falciparum, and gametocytes of Plasmodia. Its exact mechanism of action has not been determined but it appears to disrupt the mitochondria and bind to DNA.
Pharmacokinetics:
Absorption: Rapidly and well absorbed from the gastrointestinal tract. Time to peak plasma concentration: 1-3 hours.
Distribution: Widely distributed into body tissues. Enters breast milk (small amounts). Volume of distribution: Approx 150-250 L.
Metabolism: Rapidly metabolised in the liver by CYP1A2 isoenzyme to carboxyprimaquine (major active metabolite).
Excretion: Via urine (as unchanged drug in small amounts). Elimination half-life: 7 hours (range: 3.7-9.6 hours).
Chemical Structure

Chemical Structure Image
Primaquine

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 4908, Primaquine. https://pubchem.ncbi.nlm.nih.gov/compound/Primaquine. Accessed Nov. 24, 2022.

Storage
Store between 15-30°C. Protect from light.
MIMS Class
Antimalarials
ATC Classification
P01BA03 - primaquine ; Belongs to the class of aminoquinoline antimalarials.
References
Anon. Primaquine. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 24/10/2022.

Anon. Primaquine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 24/10/2022.

Buckingham R (ed). Primaquine Phosphate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 24/10/2022.

Joint Formulary Committee. Primaquine. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 24/10/2022.

Medicines for the Prevention of Malaria While Traveling: Primaquine. Centers for Disease Control and Prevention. https://www.cdc.gov. Accessed 24/10/2022.

Primaquine Phosphate Tablet (PD-Rx Pharmaceuticals, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 24/10/2022.

Primaquine Tablet (Pharmaniaga Manufacturing Berhad). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 24/10/2022.

Treatment of Malaria: Guidelines for Clinicians (United States). Centers for Disease Control and Prevention. https://www.cdc.gov. Accessed 24/10/2022.

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