What is the prophylaxis for Pneumocystis pneumonia (PCP)?

From the Guidelines

Pneumocystis pneumonia (PCP) prophylaxis is recommended for immunocompromised patients, and the first-line regimen is trimethoprim-sulfamethoxazole (TMP-SMX) at a dose of one double-strength tablet (160mg/800mg) daily or one single-strength tablet (80mg/400mg) daily, as supported by the most recent evidence from 2023 1.

Key Points

• PCP prophylaxis should be considered in patients with autoimmune inflammatory rheumatic diseases (AIIRD) in whom high doses of glucocorticoids are used, especially in combination with immunosuppressants, depending on the risk–benefit ratio 1.
• For patients who cannot tolerate TMP-SMX, alternatives include dapsone 100mg daily, atovaquone 1500mg daily with food, or aerosolized pentamidine 300mg monthly via nebulizer 1.
• Prophylaxis should continue until immune reconstitution occurs, typically when CD4 counts remain above 200 cells/μL for at least 3-6 months on effective antiretroviral therapy for HIV patients, or for non-HIV immunocompromised patients, prophylaxis duration depends on the expected period of immunosuppression 1.
• TMP-SMX is preferred because it also provides protection against toxoplasmosis and certain bacterial infections, but alternatives should be considered in patients with a history of adverse reactions or intolerance 1.

Monitoring and Side Effects

• Patients should be monitored for side effects such as rash, fever, cytopenia, or elevated liver enzymes, and alternative prophylactic medications should be considered in case of adverse events 1.
• The most commonly used prophylaxis scheme is TMP-SMX, but reduced doses (e.g., half-strength, daily) may also be effective and associated with fewer adverse events 1.

From the FDA Drug Label

For the treatment of documented Pneumocystis carinii pneumonia and for prophylaxis against Pneumocystis carinii pneumonia in individuals who are immunosuppressed and considered to be at an increased risk of developing Pneumocystis carinii pneumonia Prophylaxis against PCP is indicated in individuals who are immunosuppressed and considered to be at an increased risk of developing Pneumocystis carinii pneumonia, using trimethoprim 2.

From the Research

Prophylaxis PCP

• The most effective agent for PCP prophylaxis is trimethoprim-sulfamethoxazole (TMP-SMX), which has been shown to be superior to other regimens such as dapsone-based regimens and aerosolized pentamidine 3.
• TMP-SMX is also the only agent that has been shown to confer a mortality benefit compared to no treatment or placebo 3.
• However, TMP-SMX is also associated with a higher risk of discontinuation due to toxicity, with common adverse events including myelosuppression and renal toxicity 3, 4.
• Alternative regimens such as atovaquone and pentamidine may be considered for patients who are intolerant to TMP-SMX, with atovaquone showing promising results in terms of efficacy and tolerability 4, 5.
• The optimal dosing strategy for TMP-SMX is still a topic of debate, with some studies suggesting that a low-dose regimen may be effective in preventing PCP while minimizing toxicity 5, 6.
• In pediatric oncology patients, twice weekly prophylaxis with TMP-SMX may not be sufficient to prevent PCP, with a higher incidence of PCP observed in this population 7.

PCP Prophylaxis Regimens

• TMP-SMX is the first-line agent for PCP prophylaxis, due to its efficacy, cost, and availability 3, 6.
• Dapsone-based regimens and aerosolized pentamidine are alternative options for patients who are intolerant to TMP-SMX 3, 4.
• Atovaquone is a promising alternative regimen, with a favorable efficacy and tolerability profile 4, 5.
• Pentamidine is also an option for PCP prophylaxis, although it may be associated with a higher risk of adverse events such as asthma 4.

Special Populations

• In patients with connective tissue diseases, TMP-SMX may need to be discontinued due to adverse events, with alternative regimens such as atovaquone and pentamidine considered 4.
• In pediatric oncology patients, alternative regimens such as atovaquone and pentamidine may be considered due to the higher incidence of PCP observed with twice weekly TMP-SMX prophylaxis 7.
• In HIV-infected patients, TMP-SMX remains the first-line agent for PCP prophylaxis, although alternative regimens such as atovaquone and pentamidine may be considered for patients who are intolerant to TMP-SMX 3, 6.