Primaquine Phosphate

Antimalarial; 8-aminoquinoline derivative.100

Contraindications

• Acutely ill patients who have systemic disease manifested by a tendency to develop granulocytopenia (e.g., rheumatoid arthritis, lupus erythematosus).100

• Patients receiving other potentially hemolytic drugs or agents capable of depressing the myeloid elements of bone marrow.100

• CDC states contraindicated for prevention or treatment of malaria in individuals with G-6-PD deficiency, in pregnant women, and during lactation (unless the woman and breast-fed infant have been determined not to have G-6-PD deficiency).115 143

Warnings/Precautions

Warnings

Acute hemolytic anemia, possibly fatal, may occur if used in patients with G-6-PD deficiency.100 115 Perform appropriate laboratory testing to rule out G-6-PD deficiency before initiating primaquine.115 143 156

Hemolytic anemia may also occur if administered to individuals with other defects of the erythrocytic pentose phosphate pathway of glucose metabolism or in patients with certain hemoglobinopathies.100

Severity of hemolytic anemia depends on dosage and specific genetic defect in the individual with G-6-PD deficiency.100 In American and African blacks with G-6-PD deficiency, hemolysis may be mild, self-limiting, and asymptomatic; in individuals of Mediterranean or certain Asian extractions, hemolysis may be severe.a

Monitor closely if used in individuals who have had a previous idiosyncratic reaction to primaquine (as manifested by hemolytic anemia, methemoglobinemia, or leukopenia), individuals with a personal or family history of favism, or individuals with G-6-PD deficiency or NADH methemoglobin reductase deficiency.100

Monitor CBCs periodically during therapy.100 Do not exceed recommended dosage.100

Discontinue immediately if evidence of hemolytic anemia occurs (e.g., darkening of urine, marked fall in hemoglobin level or erythrocyte count).100

General Precautions

Nausea, vomiting, epigastric distress, and abdominal cramps reported;100 may be decreased by administration with food.121 134

Specific Populations

Category C.b

Manufacturer states avoid during pregnancy; safe use during pregnancy not established.100

CDC and other experts state contraindicated for prevention or treatment of malaria in pregnant women.115 134 143

If a pregnant women requires treatment of P. vivax or P. ovale malaria, CDC recommends oral chloroquine (300 mg once weekly) for prophylaxis for the duration of the pregnancy and deferral of primaquine (to provide a radical cure) until after delivery and after the women has been tested and determined not to have G-6-PD deficiency.143 144

CDC states contraindicated during lactation, unless the woman and breast-fed infant have been determined not to have G-6-PD deficiency.115

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults.100

Select dosage with caution (starting at the low end of dosage range) because of age-related decreases in hepatic, renal, and/or cardiac function and potential for concomitant disease and drug therapy.100

Common Adverse Effects

Hematologic effects (hemolytic anemia, leukocytosis, leukopenia); GI effects (nausea, vomiting, epigastric distress, abdominal cramps).100

Storage

Oral

25°C (may be exposed to 15–30°C) in tight, light-resistant container.100

• Necessity of taking protective measures to reduce contact with mosquitoes (protective clothing, insect repellents, mosquito nets, remaining in air-conditioned or well-screened areas).115 121 134

• Possibility of contracting malaria during travel, regardless of prophylactic regimen used.115 121 134

• Importance of seeking medical attention as soon as possible if febrile illness develops during or after return from a malaria-endemic area and of informing clinician of possible malaria exposure.115 121 134

• Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, and any concomitant illnesses.100

• Importance of women informing clinician if they are or plan to become pregnant or plan to breast-feed.100 115 143

• Importance of advising patients of other important precautionary information.100 (See Cautions.)

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name