<prompt> Dose of chloroquine for prophylaxis against vivax malaria: September 2012150 mg base weekly300 mg base weekly600 mg base weekly900 mg base weekly  <response>: 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 