Paper II — 2021 December (Supplementary) (2010 Scheme) — Q1
4 min read
Paper II
2021 December (Supplementary) (2010 Scheme)
Question
Read the case history and answer the following questions: An 18 years old boy was
brought to the outpatient department with history of fever with chills and shivering for
the past three days. Peripheral blood smear showed presence of intra erythrocytic
P.vivax parasite. (2+2+2)
Prescribe drugs treatment for the patient with dosage schedules.
Explain the mechanism of action of chloroquine.
What are the adverse effects of chloroquine when used for prolonged
period in large doses
Q16 marksEssays
Answer
Drug treatment with dosage schedule
Chloroquine: 25 mg base/kg total over 3 days (e.g., 10 mg/kg on day 1, 10 mg/kg on day 2, 5 mg/kg on day 3) — for the acute blood-stage infection
Primaquine: 0.25 mg/kg/day for 14 days — for radical cure, to eradicate the dormant hepatic hypnozoites and prevent relapse (after excluding G6PD deficiency)
Mechanism of action of chloroquine
Concentrates in the parasite’s food vacuole and inhibits haem polymerase, which normally converts toxic free haem (released during haemoglobin digestion) into inert haemozoin
Accumulated toxic free haem damages the parasite’s membranes and proteins, killing it
Adverse effects with prolonged high-dose use
Retinopathy and corneal deposits (can cause irreversible visual loss)
