Overview
DESCRIPTION Primaquine phosphate is 8-[(4-amino-1-methylbutyl) amino]-6-methoxyquinoline phosphate, a synthetic compound with potent antimalarial activity. The molecular formula of primaquine phosphate is C 15 H 21 N 3 O·2H 3 PO 4 and its molecular weight is 455.34. The structural formula of primaquine phosphate is: Figure 1: Primaquine phosphate structure.
Mechanism of Action
CLINICAL PHARMACOLOGY Microbiology Mechanism of Action Primaquine phosphate is an 8-aminoquinoline antimalarial drug. The mechanism of action has not been fully established. The major assumptions are an inhibition of the mitochondrial system of dormant parasites, and an oxidative stress generated through reactive metabolites in infected cells. In humans, primaquine phosphate activity is probably related to hydroxylated metabolites generated intrahepatically by CYP2D6. Antimicrobial Activity Primaquine phosphate is active against the dormant liver forms of P.vivax , namely hypnozoites, as well as exoerythrocytic stages of the parasite. Thereby, it prevents the development of the blood (erythrocytic) forms of the parasite which are responsible for relapses in vivax malaria.
Indications
- INDICATIONS AND USAGE Primaquine phosphate is indicated for the radical cure (prevention of relapse) of vivax malaria.
Common Doses
- 15 mg
Dosage
DOSAGE AND ADMINISTRATION Primaquine phosphate tablets are recommended only for the radical cure of vivax malaria, the prevention of relapse in vivax malaria, or following the termination of chloroquine phosphate suppressive therapy in an area where vivax malaria is endemic. Patients suffering from an attack of vivax malaria or having parasitized red blood cells should receive a course of chloroquine phosphate, which quickly destroys the erythrocytic parasites and terminates the paroxysm.
Contraindications
- CONTRAINDICATIONS Known hypersensitivity reactions to primaquine phosphate, other 8-aminoquinolones, or to any component in primaquine. Severe glucose-6-phosphate dehydrogenase (G6PD) deficiency (see WARNINGS, Hemolytic Anemia ). Pregnant women (see WARNINGS, Pregnancy ). Breastfeeding by a lactating woman when the infant is found to be G6PD deficient or if G6PD status is unknown (see WARNINGS, Nursing Mothers ). Because quinacrine hydrochloride appears to potentiate the toxicity of antimalarial compounds which are structurally related to primaquine, the use of quinacrine in patients...
Side Effects
- ADVERSE REACTIONS To report SUSPECTED ADVERSE REACTIONS, please call Ingenus Pharmaceuticals, LLC at 1-877-748-1970 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch Gastrointestinal: Nausea, vomiting, epigastric distress, abdominal cramps. Hematologic: Leukopenia, hemolytic anemia, decreased hemoglobin, methemoglobinemia. Hemolytic anemia occurs commonly in patients with G6PD deficiency and may be severe or fatal in patients with severe G6PD deficiency (see WARNINGS ). Methemoglobin levels are usually
Interactions
- Drug Interactions Pharmacodynamics Interactions Quinacrine Concurrent use of quinacrine (mepacrine) and primaquine are contraindicated. Increased toxicity was seen when quinacrine was used with pamaquine, another 8-aminoquinoline (see CONTRAINDICATIONS ). Hemolytic Agents and Methemoglobinemia-Inducing Drugs The concurrent administration of hemolytic agents or methemoglobinemia-inducing drugs and primaquine should be avoided (see PRECAUTIONS ). If the concurrent administration cannot be avoided, close blood monitoring is required.