This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Dose of chloroquine for prophylaxis against vivax malaria: September 2012 
Select and explain. 
A. 150 mg (base) weekly, B. 300 mg (base) weekly, C. 600 mg (base) weekly, D. 900 mg (base) weekly
B: 300 mg (base) weekly
Answer: B: 300 mg (base) weekly 
Explanation: Ans. B i.e. 300 mg (base) weekly Antimalarial prophylaxis In areas where chloroquine remains effective: Chloroquine 300 to 310 mg once weekly, and Proguanil 200 mg once daily (staed one week before travel, and continued for four weeks after returning)