anti-protozoa_part3

Question 1

What type of drug is Primaquine, and how is it metabolized?

Answer 1

The only 8-aminoquinoline used drug (least toxic). Well absorbed. Rapidly metabolized by demethylation and oxidation. Metabolites excreted in urine.

Question 2

What is the mechanism of action of Primaquine?

Answer 2

The exact mechanism of action is not well known.

Question 3

What is the antimalarial action of Primaquine?

Answer 3

Active against late hepatic stages (hypnozoites) of P. vivax and P. ovale. The only drug that can achieve radical cure of these infections. Has gametocidal action. Not useful for treatment of acute attacks (effect on blood schizonts is too slight).

Question 4

What are the clinical uses of Primaquine?

Answer 4

1) Terminal prophylaxis of P. vivax and P. ovale malaria, usually with a blood schizonticidal drug (e.g., chloroquine).
2) Radical cure of acute P. vivax and P. ovale infection in combination with chloroquine. 3) Gametocidal action.
4) Treatment of Pneumocystis carinii pneumonia in combination with clindamycin.

Question 5

What are the adverse effects of Primaquine?

Answer 5

1) Cramps, nausea, headache.
2) Cyanosis (methaemoglobinaemia).
3) Hemolysis in individuals with G6PD deficiency (affecting RBCs).