A Controlled Trial of Aerosolized Pentamidine or Trimethoprim–Sulfamethoxazole as Primary Prophylaxis againstPneumocystis cariniiPneumonia in Patients with Human Immunodeficiency Virus Infection

Abstract
Primary prophylaxis against Pneumocystis carinii pneumonia (PCP) is recommended for patients with human immunodeficiency virus (HIV) infection if their CD4 cell counts are below 200 per cubic millimeter (0.2×109 per liter). Either aerosolized pentamidine or trimethoprim–sulfamethoxazole (co-trimoxazole) is commonly prescribed for prophylaxis, but the relative efficacy and toxicity of these agents are unknown.