Opportunistic infections in HIV, Prophylaxis

Patients with HIV / AIDS and other severe immunodeficiency diseases are at risk for certain opportunistic infections. Susceptibility to opportunistic infections can be measured by CD4+ T lymphocyte counts.

• Pneumocystis pneumonia: Patients with a CD4+ count <200 cells/mm3 should receive Bactrim DS (trimethoprim/sulfamethoxazole) for prevention of Pneumocystis pneumonia. Rx: Take 1 Bactrim DS PO three times weekly 
• Histoplasma capsulatum: Itraconazole is used to prevent Histoplasma capsulatum infection when the CD4+ count is ≤ 150 cells/mm3 if the patient is at risk due to occupational exposure or living in a community with a hyperendemic rate of histoplasmosis (>10 cases per 100 patient years).
• Toxoplasma gondii: Prophylaxis against Toxoplasma gondii should also be given if the CD4+ count is <100 cells/mm3. Bactrim DS (Trimethoprim-sulfamethoxazole) is effective. Rx: Take 1 Bactrim DS PO three times weekly.  Alternatives are pyrimethamine-dapsone and pyrimethamine-sulfadoxine
• Mycobacterium avium intracellulare(MAC): Azithromycin is used to prevent infection with Mycobacterium avium-intracellulare complex when CD4+ count is <50 cells/mm3.