Antimalarials

Question 1

what type of parasites do drugs target in malaria caused by P. falciparum and P. malariae

Answer 1

Only one cycle of liver cell invasion
Liver infections ceases in < 4 weeks
Only erythrocytic parasites have to be eliminated

Question 2

what type of parasites do drugs target in malaria caused by P. vivax and P. ovale

Answer 2

Have a dormant hepatic stage

Erythrocytic and hypozoite (hepatic parasites) have to eliminated

Question 3

Which parasite causes most severe disease and symptoms

Answer 3

P. falciparum –> only species to cause fatal disease if untreated

Microvascular effects:
Cerebral malaria (irritability --> seizures --> coma) 
Respiratory distress syndrome 
Diarrhea 
Severe thrombocytopenia 
Spontaneous abortion 
Hypoglycemia

Question 4

Lab diagnosis of malaria

Answer 4

Thick blood smear = to look for parasite

Thin blood smear = to look for gametocyte

Question 5

How does treatment of complicated vs uncomplicated malaria differ

Answer 5

Uncomplicated = oral antimalarials
Complicated = parenteral antimalarials

Question 6

Which species shows chloroquine resistance

Answer 6

P. falciparum

Question 7

Chloroquine MOA, PK, resistance

Answer 7

Only works against blood parasites (not liver stage parasites)

Concentrates in parasite food vacuoles –> prevents biocrystallization of Hb breakdown product heme to non-toxin hemozoin –> Heme will build up, is toxin to parasite and cause lysis of RBCs and parasite

Oral, taken weekly

Resistance = P. falciparum –> mutations in putative transporter PfCRT are common

Question 8

Chloroquine AE

Answer 8

Pruritus - common in africans
Hemolysis - is G6PD patients
Can cause ECG changes
N/V, blurry vision, malaise (uncommon)

Question 9

Chloroquine contraindications

Answer 9

patients with

• psoriasis or porphyria
• retinal or visual field disturbances

safe in pregnancy and young children

Question 10

Quinine and quinidine MOA, uses

Answer 10

First line for severe falciparum disease