Primaquine Phosphate

A to Z Drug Facts

 Action Disrupts metabolic processes of parasitic organism, eliminating tissue (exoerythrocytic) infection and preventing development of blood (erythrocytic) forms of parasite responsible for relapses of vivax malaria.

 Indications Radical cure or prevention of relapse in vivax malaria; after termination of chloroquine phosphate suppressive therapy in areas where vivax malaria is endemic. Unlabeled use(s): With clindamycin, treatment of Pneumocystis carinii pneumonia associated with AIDS.

 Contraindications Concomitant administration of quinacrine and primaquine; acutely ill patient with systemic disease manifested by granulocytopenia (eg, rheumatoid arthritis, lupus erythematosus); concurrent administration of other potentially hemolytic or bone marrow depressant medications.

 Route/Dosage

Begin therapy during last 2 wk of or after course of suppression with chloroquine or comparable drug. ADULTS: PO 26.3 mg (15 mg base) for 14 days. CHILDREN: PO 0.5 mg/kg/day (0.3 mg/kg/day of base) for 14 days (maximum 15 mg/day of base).

 Interactions

Quinacrine: May potentiate toxicity of antimalarial compounds that are structurally related to primaquine.

 Lab Test Interferences None well documented.

 Adverse Reactions

GI: Nausea; vomiting; epigastric distress; abdominal cramps. HEMA: Leukopenia; hemolytic anemia in G-6-PD deficiency; methemoglobinemia in NADH methemoglobin reductase deficiency.

 Precautions

Pregnancy: Pregnancy category undetermined. Lactation: Undetermined. To avoid adverse effects in the infant, do not give to lactating women. Hemolytic anemia: May occur in patients with following conditions: G-6-PD deficiency, NADH methemoglobin reductase deficiency; idiosyncratic reactions (leukopenia, methemoglobinemia; hemolytic anemia). Discontinue drug if marked darkening of urine or sudden decrease in hemoglobin or leukocyte count occurs. Maximum dose: Hemolytic reactions may occur with doses of drug exceeding recommended dose.

 Administration/Storage

• Do not begin administration unless patient has completed or is within 2 wk of completing course of suppression with chloroquine or comparable drug.
• Do not administer to patient who is taking or has recently received quinacrine within past 3 mo.
• Administer with food if medicine causes GI upset.
• Store at room temperature in tightly-closed, light-resistant container.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note recent use of quinacrine and other antimalarial agents.
• Ensure that CBC with differentials have been obtained before beginning therapy and are performed routinely during therapy.
• Monitor for hemolytic reactions (eg, marked darkening of urine or sudden decrease in hemoglobin concentration or leukocyte or erythrocyte count); notify physician if these reactions occur.

 Patient/Family Education

• Tell patient that medicine may be taken with food if stomach upset (eg, nausea, vomiting, abdominal cramps) occurs, and advise patient to contact physician if upset persists.
• Emphasize importance of compliance with drug regimen.
• Advise patient to report marked darkening of urine to physician.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts