What is the recommended PCP prophylaxis for HIV patients with a CD4 count under 200?

The recommended prophylaxis for Pneumocystis pneumonia (PCP) in HIV patients with a CD4 count under 200 cells/mm³ is TMP-SMX, commonly known as Bactrim. This recommendation is based on substantial evidence that TMP-SMX effectively reduces the incidence of PCP, a potentially life-threatening opportunistic infection that can occur in immunocompromised individuals, particularly those with advanced HIV/AIDS.

TMP-SMX works by inhibiting the growth of the Pneumocystis jirovecii organism, thereby preventing the development of PCP. The initiation of prophylaxis at a CD4 count of less than 200 is crucial since patients in this category are at significantly higher risk for infections that can lead to severe illness or complications.

Other options do not serve as the first line for PCP prophylaxis. Azithromycin is typically used for other infections and not for PCP. Dapsone can be an alternative but is usually considered when there are contraindications to TMP-SMX, such as severe allergies or adverse reactions. Acyclovir is an antiviral medication effective against herpes viruses and has no role in the prevention of PCP. Therefore, TMP-SMX is the preferred and most appropriate choice for prophylaxis against PCP in this patient population.