Primaquine
Mechanism :
Primaquine is an 8-aminoquinoline compound which eliminates tissue erythrocytic infection. Thereby, it prevents the development of the erythrocytic forms of the parasite which are responsible for relapses in vivax and ovale malaria. Primaquine phosphate is also active against gametocytes of P. falciparum.
Indication :
- Preventing relapse of P. vivax and P. ovale.
- Falciparum malaria as an anti-gametocyte.
- Malaria prophylaxis.
Contraindications :
Contraindicated in acutely ill patients suffering from systemic disease manifested by tendency to granulocytopenia, such as rheumatoid arthritis and lupus erythematosus, in patients receiving concurrently other potentially hemolytic drugs or depressants of myeloid elements of the bone marrow. It appears to potentiate the toxicity of antimalarial compounds which are structurally related to primaquine; therefore, the use of quinacrine in patients receiving primaquine is contraindicated. Similarly, primaquine should not be administered to patients who have received quinacrine recently, as toxicity is increased. Use with caution and follow the weekly dosing regimen in patients with G6PD deficiency, as acute hemolytic anemia can occur.
Dosing :
Preventing relapse of P. vivax and P. ovale:
0.25-0.5 mg base/kg/day for 14 days (Max: 30 mg/day). In patients with G-6-PD deficiency, 1-12 years: 0.5-0.75 mg/kg and 12-18 years: 30 mg once in a week for 8 weeks.
In falciparum malaria, as anti-gametocyte:
0.25 mg/kg single dose.
Malaria prophylaxis:
0.5 base/kg/day. Start: 1-2 days before exposure; Max: 30 mg/day. Stop after 7 days after return from endemic area.
Adverse Effect :
Contraindicated in acutely ill patients suffering from systemic disease manifested by tendency to granulocytopenia, such as rheumatoid arthritis and lupus erythematosus, in patients receiving concurrently other potentially hemolytic drugs or depressants of myeloid elements of the bone marrow. It appears to potentiate the toxicity of antimalarial compounds which are structurally related to primaquine; therefore, the use of quinacrine in patients receiving primaquine is contraindicated. Similarly, primaquine should not be administered to patients who have received quinacrine recently, as toxicity is increased. Use with caution and follow the weekly dosing regimen in patients with G6PD deficiency, as acute hemolytic anemia can occur.
Nausea, vomiting, epigastric distress, abdominal cramps, leukopenia, hemolytic anemia in G-6-PD deficient individuals, methemoglobinemia in NADH methemoglobin reductase deficient individuals, headache, pruritus, and interference with visual accommodation.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Dose as in normal renal function |
| <10 | Dose as in normal renal function |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unknown dialysability. Dose as in normal renal function |
| HD | Not dialysed. Dose as in normal renal function |
| HDF/High flux | Unknown dialysability. Dose as in normal renal function |
| CAV/VVHD | Unknown dialysability. Dose as in normal renal function |
Hepatic Dose :
Dose adjustment guidelines are not available, dose adjustment may be required as drug undergoes extensive hepatic metabolization to active compound. Initiation of therapy at low dose may be done, caution should be taken when using in patients with hepatic impairment.