Pneumocystis prophylaxis

1. See Also
   1. Pneumocystis carinii (Pneumocystis jiroveci)
2. Indications: Start prophylaxis
   1. CD4 Count < 200
   2. Constitutional symptoms regardless of CD4 Count
      1. Oral Candidiasis (Thrush)
      2. Unexplained fever > 2 weeks
   3. Prior history of Pneumocystis
      1. Second episode PCP Pneumonia within 1 year: 30-60%
3. Indications: Stop prophylaxis
   1. CD4 Count > 200 (stable for at least 3 months) and
   2. Triple Antiretroviral therapy >6 months
   3. Also applies to MAC, Cryptococcus, Toxoplasmosis
   4. References
      1. (2002) Ann Intern Med 137(4): 239-250
4. Efficacy
   1. Bactrim daily is extremely effective in preventing PCP
   2. Also decreases the Incidence of bacterial infections
   3. Decreases the Incidence of ToxoplasmosisEncephalitis
      1. Patients with previous Toxoplasmosis infection
5. Dosing: First line
   1. Trimethoprim-sulfamethoxazole (TMP-SMZ, Bactrim, Septra) DS daily
      1. More effective then other measures when CD4 < 200
      2. Prevents first and recurrent episodes of Pneumocystis
6. Dosing: Other agents
   1. Aerosolized Pentamidine
      1. 300 mg q month reduces the risk of PCP by 60-80%
      2. Well tolerated (cough and bronchospasm in 50-66)
   2. Dapsone 100 mg PO qd
      1. Add Pyrimethamine for Toxoplasmosis coverage
      2. Screen for G6PD prior to use
7. Adverse Effects
   1. Significantly reduced adverse effects with Bactrim SS
      1. Bactrim DS no more effective than Bactrim SS
      2. Reference
         1. Schneider (1995) J Infect Dis 171:1632-6
   2. Adverse reactions to Bactrim in >3 months of use
      1. Requires discontinuation in 25% of patients