Dosing and uses of Primaquine
Adult dosage forms and strengths
tablet
- 26.3mg
Prevention of relapse of P. vivax malaria
30 mg PO qDay for 14 days
Uncomplicated P. vivax and P. ovale malaria (off-label)
30 mg PO qDay for 14 days with chloroquine or hydroxychloroquine
Alternatively, for mild G6PD deficiency or as alternative to daily regimen: 45 mg PO qDay for 8 weeks (only to be used after consultation with an infectious disease/tropical medicine expert
Chemoprophylaxis (Off-label)
P. vivax and P. ovale maleria: 30 mg PO qDay for 14 days after departure from malaria-endemic area
P. Jiroveci Pneumonia (Orphan)
For use in combination with clindamycin in the treatment of P. Jiroveci pneumonia associated with AIDs
15-30 mg base PO qD for 21 days (with clindamycin IV or PO)
Orphan indication sponsor
- Sanofi Winthrop, Inc; 90 Park Avenue; New York, NY 10016
Other Information
Monitor: CBC
Pediatric dosage forms and strengths
tablet
- 26.3mg
Uncomplicated P. vivax and P. ovale malaria (Off-label)
0.5 mg/kg (30 mg/day maximum) qDay for 14 days with chloroquine or hydroxychloroquine
Chemoprophylaxis
0.5 mg/kg PO qDay (30 mg/day maximum); start 1-2 days prior to travel and continue for 7 days after departure from malaria endemic area
Primaquine adverse (side) effects
>10%
Abdominal pain
Hemolytic anemia in G6PD deficiency
Nausea
Vomiting
<1-10%
Methemoglobinemia in NADH-methemoglobin reductase-deficient individuals
<1%
Agranulocytosis
Arrhythmias
Headache
Interference with visual accommodation
Leukopenia
Leukocytosis
Rash
Dizziness
Pruritus
Warnings
Contraindications
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
Cautions
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 (<50 bpm), and during concomitant administration with QT interval prolonging agents
Pregnancy and lactation
Safe usage in pregnancy not established; use during pregnancy should be avoided except when in judgment of the physician benefit outweighs possible hazard
Lactation: CDC recommends do not use in nursing women unless breast-fed infant has been determined not to have G6PD deficiency
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Primaquine
Absorption: well absorbed
Metabolism: hepatic to carboxyprimaquine (active)
Half-life, Elimination: 3.7-9.6 hr
Peak Plasma Time: 1-2 hr
Excretion: urine (small amounts as unchanged drug)
Mechanism of action
Disrupts Plasmodium mitochondria
