From the Guidelines
Toxoplasmosis prophylaxis should be considered in HIV-infected patients when their CD4 count falls below 100 cells/μL, although specific guidelines recommend consideration at a CD4+ T lymphocyte percentage of <14% or a history of an AIDS-defining illness 1. The recommended first-line regimen is trimethoprim-sulfamethoxazole (TMP-SMZ), typically given as one double-strength tablet daily, which confers cross-protection against toxoplasmosis and selected common respiratory bacterial infections 1. Some key points to consider when initiating toxoplasmosis prophylaxis include:
- The CD4 count threshold for initiating prophylaxis, with consideration for patients with a history of AIDS-defining illnesses or low CD4 percentages 1
- The use of TMP-SMZ as the first-line prophylactic agent due to its efficacy and cross-protective benefits 1
- Alternative prophylactic regimens, such as dapsone plus pyrimethamine with leucovorin, or atovaquone with or without pyrimethamine, for patients who cannot tolerate TMP-SMZ 1
- The importance of regular CD4 count monitoring to determine the need for prophylaxis and to assess the effectiveness of antiretroviral therapy 1. Initiating chemoprophylaxis at a CD4+ T lymphocyte count of >200, but <250 cells/µL, should also be considered when monitoring CD4+ T lymphocyte counts for ≥ 3 months is not possible 1. It is essential to weigh the benefits and risks of prophylaxis, considering the potential for adverse reactions and the need for desensitization or alternative regimens 1.
From the Research
Toxoplasmosis Prophylaxis in HIV Patients
- Toxoplasmosis prophylaxis is recommended for HIV patients with a CD4 count below 200 cells/μl 2
- The most effective regimen for toxoplasmosis prophylaxis is trimethoprim/sulfamethoxazole (TMP/SMX) 3, 4
- Alternative regimens include dapsone in combination with pyrimethamine therapy 3 and pyrimethamine/sulfadiazine 5
- Prophylaxis can be safely discontinued in HIV-infected patients after immunological restoration with highly active antiretroviral therapy, when the CD4+ T cell count increases to >200 cells/mm3 for >3 months 6
CD4 Count and Toxoplasmosis Prophylaxis
- A CD4 count below 100 cells/μl is considered a high risk for toxoplasmosis, and prophylaxis with cotrimoxazole or dapsone + pyrimethamine is recommended for 6 months 2
- A CD4 count below 200 cells/μl is considered a risk for toxoplasmosis, and prophylaxis with TMP/SMX is recommended 3, 4