Anti-parasitic Drugs

Question 1

What are the 2 categories of the anti parasitic drugs?

Answer 1

Anti- protozoal

Anti-helminthic

Question 2

What are the targets for malaria drugs?

Answer 2

Tissue schizonticides
Blood schizonticides
Gametocites
PK: oral or IV,metabolized in liver and excreted to urine
AE: common toxicity-rash, headache, dizziness, ocular toxicity

Question 3

What are the treatments for malaria?

Answer 3

Acute attack- drugs against erythrocytic form (chloroquine)
Prevention of relapse-drugs kill liver form (Primaquine)
Prophylaxis-drug inhibit erythrocyte stage (chloroquine, mefloquine)

Question 4

What are the characteristics of chloroquine?

Answer 4

Most versatile antimalarial available
Used fo effective treatment of erythrocyte stage and prophylaxis
Safe to use during pregnancy 
Use for extra-intestinal amoebiasis
Not effective in liver form
P.falciparum develop resistance
PK: rapid oral absorption, excellent tissue distribution
Antacids decrease oral absorption
Unchanged drug excreted to urine

Question 5

What is the MOA of chloroquine?

Answer 5

Inhibition of heme biocrystallization
Blocks conversion of heme to hemozoin
AE: prolonged use causes auditory dysfunction (tinnitus)
High dose cause blurred vision, retinal dysfunction (retinopathy)
Resistance: membrane pumps flush out drugs
Severe anemia in patients with glucose 6 phosphatase deficiency

Question 6

What are the characteristics of Mefloquine?

Answer 6

Chemically related to quinine
Pass BBB
Used for prophylaxis
First line therapy for chloroquine resistant malaria
Safe in pregnancy
PK:oral only- other forms cause irritation
MOA: accumulate into parasite lysosome

Question 7

What are the AE of Mefloquine?

Answer 7

Cardiac arrest,cardiac conduction defects
Neurologic dysfunction-seizures, hallucinations and psychosis
Classically known to cause neuropsychiatric reactions