Drug of choice for pneumocystis carinii is:

Answer is B (Cotrimoxazole): Trimethoprim/sulfamethoxazole or Cotrimoxazole is the drug of choice for all firms of Pneumocystis Pneumonias. 'Trimethoprim-Sulfamethoxazole which acts by inhibiting folic acid synthesis is considered the drug of choice for all forms of Pneumocystis Pneumonias. Therapy is continued for 14 days in Non-HIV-Infected patients and for 21 days in HIV-Infected patients' - Harrison 18th/1672