# Pneumocystis pneumonia (PJP) prophylaxis with co-trimoxazole

Source: https://onco.cc/protocols/pneumocystis-pneumonia-prophylaxis/  
OnCo record `pneumocystis-pneumonia-prophylaxis` (Protocol). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Pneumocystis is a fungus that can cause a dangerous pneumonia in people whose immune system is weakened by some cancer treatments, steroids or a stem cell transplant. An inexpensive antibiotic, co-trimoxazole, taken a few times a week or daily, prevents it very well. People who cannot take it have other options: atovaquone, dapsone or an inhaled medicine once a month.

## Summary

AGIHO (2020) strongly recommends chemoprophylaxis for the groups its Table 7 lists at significant risk: acute lymphoblastic leukaemia, allogeneic stem cell transplant, long-term steroids above 20 mg prednisone equivalent daily for more than 4 weeks, and fludarabine with cyclophosphamide and rituximab (prevent PJP A-I, reduce mortality A-IIr), and for idelalisib, alemtuzumab and temozolomide with radiotherapy (A-IIu,t). Intermediate risk (R-CHOP14, escalated BEACOPP, nucleoside analogues, brain irradiation with high-dose steroids, CD4 below 200/µl) may or may not receive it (C-III). ASCO/IDSA (2018) set the threshold at regimens with more than 3.5% risk, for example 20 mg or more prednisone equivalent daily for a month or more, or purine analogues. ECIL-5 (2016) lists ALL, allogeneic HSCT, alemtuzumab, fludarabine with cyclophosphamide and rituximab, more than 4 weeks of corticosteroids and primary immune deficiencies in children, for the entire period at risk.

Co-trimoxazole (trimethoprim-sulfamethoxazole) is first choice (AGIHO A-IIt,r; ECIL-5 A-II adults, A-I children), at one single-strength tablet daily or one double-strength tablet daily or thrice weekly (B-IIt); ECIL-5 gives it 2 to 3 times weekly and notes children may do equally well once weekly (B-II). Second line: atovaquone 1500 mg daily with a fatty meal (A-IIt), dapsone 100 mg daily after G6PD testing (A-IIt), or aerosolised pentamidine 300 mg monthly (B-IIt), which is probably less effective and needs staff protection. For idelalisib the label asks for prophylaxis from the start and for 2 to 6 months after stopping.

## Fields

- Kind: Protocol
- Last checked: 2026-11-11
- Also known as: PJP prophylaxis; PCP prophylaxis; Pneumocystis prophylaxis; co-trimoxazole prophylaxis; Septrin prophylaxis; TMP-SMX prophylaxis; trimethoprim-sulfamethoxazole prophylaxis
- Tags: protocol; pneumocystis; infection-prevention

## Connected records

- terms: [Infection prophylaxis in lymphoma: PJP, herpes, fungal risk and vaccination](https://onco.cc/terms/lymphoma-tx-pjp-and-infection-prophylaxis/)
- cancers: [Acute lymphoblastic leukaemia](https://onco.cc/cancers/all-leukemia/), [Childhood cancers (all types)](https://onco.cc/cancers/childhood-cancers/), [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/)
- fronts: [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- technologies: [Allogeneic stem cell transplantation](https://onco.cc/technologies/allogeneic-hsct/)
- drugs: [Alemtuzumab](https://onco.cc/drugs/alemtuzumab/), [Fludarabine](https://onco.cc/drugs/fludarabine/), [Idelalisib](https://onco.cc/drugs/idelalisib/), [Rituximab](https://onco.cc/drugs/rituximab/), [Temozolomide](https://onco.cc/drugs/temozolomide/)

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