Treatment for HIV infection can be broadly divided into the following categories: (1) prophylaxis for opportunistic infections, malignancies, and other complications of HIV infection; (2) treatment of opportunistic infections, malignancies, and other complications of HIV infection; and (3) treatment of the HIV infection itself with combination antiretroviral treatment.
A. Prophylaxis for Complications of HIV Infection
In general, decisions about prophylaxis of opportunistic infections are based on the CD4 count, recent HIV viral load, and a history of having had the infection in the past. In the era prior to antiretroviral treatment, patients who started taking prophylactic regimens were maintained on them indefinitely. However, studies have shown that in patients with robust improvements in immune function—as measured by increases in CD4 counts above the levels that are used to initiate treatment—prophylactic regimens can safely be discontinued.
Because individuals with advanced HIV infection are susceptible to a number of opportunistic pathogens, the use of agents with activity against more than one pathogen is preferable. It has been shown, for example, that trimethoprim-sulfamethoxazole confers some protection against toxoplasmosis in individuals receiving this medication for Pneumocystis prophylaxis.
1. Prophylaxis against Pneumocystis pneumonia
Patients with CD4 counts below 200 cells/mcL, a CD4 lymphocyte percentage below 14%, or weight loss or oral candidiasis should be offered primary prophylaxis for Pneumocystis pneumonia. Patients with a history of Pneumocystis pneumonia should receive secondary prophylaxis until their viral load is undetectable and they have maintained a CD4 count of 200 cells/mcL or more while receiving antiretroviral treatment for longer than 3 months. Regimens for Pneumocystis prophylaxis are given in Table 31–6.
Table 31–6.Pneumocystis jirovecii prophylaxis, in order of preference. |Favorite Table|Download (.pdf) Table 31–6. Pneumocystis jirovecii prophylaxis, in order of preference.
|Medication ||Dose ||Side Effects ||Limitations |
|Trimethoprim-sulfamethoxazole ||One double-strength tablet three times a week to one tablet daily ||Rash, neutropenia, hepatitis, Stevens-Johnson syndrome ||Hypersensitivity reaction is common but, if mild, it may be possible to treat through. |
|Dapsone ||50–100 mg orally daily or 100 mg two or three times per week ||Anemia, nausea, methemoglobinemia, hemolytic anemia ||Less effective than above. Glucose-6-phosphate dehydrogenase (G6PD) level should be checked prior to therapy. Check methemoglobin level after 1 month of treatment. |
|Atovaquone ||1500 mg orally daily with a meal ||Rash, diarrhea, nausea ||Less effective than suspension trimethoprim-sulfamethoxazole; equal efficacy to dapsone, but more expensive. |
|Aerosolized pentamidine ||300 mg monthly ||Bronchospasm (pretreat with bronchodilators); rare reports of pancreatitis ||Apical P jirovecii pneumonia, extrapulmonary P jirovecii infections, pneumothorax. |
2. Prophylaxis against M avium complex infection
Patients whose CD4 counts fall to below 75–100 cells/mcL should be given prophylaxis against M avium complex infection. Clarithromycin (500 mg orally twice daily) and azithromycin (1200 mg orally weekly) have both been shown to decrease the incidence of disseminated M avium complex infection by approximately 75%, with a ...