Antiprotozoals

Question 1

Antimalarials

Answer 1

Chloroquine, Quinine

chloroquine is effective against the erythrocytic forms of all four plasmodial species.

P. falciparum is now resistant to chloroquine in most parts of the world and it does not have any effect on sporozoites, hypnozoites or gametocytes.

Its chief antimalarial action derives from an inhibition of haem polymerase, the enzyme that polymerises toxic free haem to haemozoin. This poisons the parasite and prevents it from utilising the amino acids from haemoglobin proteolysis. Chloroquine is also used as a disease-modifying antirheumatoid drug

Unwanted effects: gastrointestinal disturbances, dizziness and urticaria.

Quinine is a blood schizonticide. It may be given orally or intravenously; half-life 10 h. Unwanted effects: gastrointestinal tract disturbances, tinnitus, blurred vision and, in large doses, dysrhythmias and central nervous system disturbances.

Question 2

Metronidazole

Answer 2

an antibacterial and Antiprotozoal agent

•Active against anaerobic bacteria

•Also active against protozoa:
–Amoebae (dysentery & systemic)
–Giardia (diarrhoea)
–Trichomonas (vaginitis)