Prophylaxis for Pneumocystis jirovecii pneumonia in HIV patients with CD4 < 200 cells/µL is with which drug?

• A. Trimethoprim-sulfamethoxazole
• B. Azithromycin
• C. Fluconazole
• D. Acyclovir

Answer: (A)

Prophylaxis against Pneumocystis jirovecii pneumonia is recommended in HIV patients when the CD4 count falls below 200 cells/µL because the risk of PCP becomes high at that level. The drug of choice for this prophylaxis is trimethoprim-sulfamethoxazole because it has strong activity against Pneumocystis jirovecii and has been shown to dramatically reduce the incidence of PCP. It’s also convenient and cost-effective, and, in people who are seropositive for Toxoplasma gondii, the sulfamethoxazole component provides additional protection.

The other options don’t prevent PCP because they lack activity against Pneumocystis. Azithromycin is used for certain bacterial infections and MAC prophylaxis but not PCP. Fluconazole targets fungal pathogens like Candida and Cryptococcus, not Pneumocystis. Acyclovir is an antiviral for herpesviruses and does not prevent PCP. If someone cannot take TMP-SMX, alternatives include dapsone, atovaquone, or pentamidine, but these are used only when TMP-SMX is not suitable.