Safe and Effective Prophylaxis with Bimonthly Intravenous Pentamidine in the Pediatric Hematopoietic Stem Cell Transplant Population
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Updated: Apr 1, 2026
Author Spotlight: Exploring the Lifespan Dynamics of Healthy Human Hematopoiesis
Published on: December 8, 2023
Emily R Levy1, Lisa Musick, Matthew S Zinter
1From the *Division of General Pediatrics, †Division of Pediatric Allergy, Immunology, and Blood and Marrow Transplant, and ‡Division of Pediatric Critical Care, University of California San Francisco Benioff Children's Hospital, San Francisco, California; §Valley Family Medicine, University of Washington, Seattle, Washington; and ¶Division of Infectious Disease, University of California San Francisco Benioff Children's Hospital, San Francisco, California.
Insights
Bimonthly intravenous pentamidine effectively prevented Pneumocystis pneumonia (PCP) in pediatric hematopoietic stem cell transplant (HCT) patients, including infants. This regimen demonstrated comparable safety to monthly dosing, making it a viable second-line PCP prophylaxis option.
Area of Science:
- Pediatric Hematology/Oncology
- Infectious Disease Prevention
- Stem Cell Transplantation
Background:
- Pneumocystis pneumonia (PCP) poses a significant mortality risk (over 50%) in pediatric hematopoietic stem cell transplant (HCT) patients without prophylaxis.
- Trimethoprim-sulfamethoxazole is standard, but pentamidine is used second-line due to potential cytopenias.
- Monthly intravenous (IV) pentamidine shows variable efficacy and higher breakthrough rates in young children.
Purpose of the Study:
- To evaluate the safety and efficacy of bimonthly (twice-monthly) IV pentamidine for PCP prophylaxis in pediatric HCT patients.
- To determine if a more frequent dosing schedule improves outcomes compared to monthly administration.
Main Methods:
- Retrospective analysis of pediatric HCT patients receiving bimonthly IV pentamidine from December 2006 to June 2013.
- Data collected included demographics, clinical course, prophylaxis rationale, laboratory values, and adverse events.
- Focus on patients younger than 2 years at initiation and reasons for pentamidine use (e.g., cytopenias).
Main Results:
- 111 pediatric HCT patients received bimonthly IV pentamidine (574 doses).
- 12.6% of patients experienced side effects leading to discontinuation; 3 had hypotension/anaphylaxis, 3 had pancreatic dysfunction.
- No PCP cases (0%) were observed during or after bimonthly IV pentamidine prophylaxis, even in patients under 2 years.
Conclusions:
- Bimonthly IV pentamidine demonstrates comparable safety to monthly dosing for PCP prophylaxis in pediatric HCT recipients.
- This regimen was highly effective in preventing PCP, including in very young children.
- Bimonthly IV pentamidine is a recommended second-line PCP prophylaxis option for pediatric HCT patients.
Background:
Without prophylaxis, Pneumocystis jiroveci pneumonia (PCP) develops in 5%-15% of pediatric hematopoietic stem cell transplant (HCT) patients with mortality above 50%. Trimethoprim-sulfamethoxazole is a standard PCP prophylaxis; pentamidine is frequently used as second-line prophylaxis because of trimethoprim-sulfamethoxazole's potential for cytopenias. Monthly intravenous (IV) pentamidine has variable efficacy with PCP infection rates of 0%-10% in pediatric patients, and higher breakthrough rates in those younger than 2 years. We hypothesized that bimonthly (twice monthly) pentamidine might have equivalent safety and improved efficacy; therefore, we conducted a retrospective analysis of bimonthly pentamidine PCP prophylaxis.
Methods:
We retrospectively reviewed records of all pediatric HCT patients who received bimonthly IV pentamidine between December 2006 and June 2013, and collected data regarding demographics, clinical course, prophylaxis rationale, laboratory values and adverse events.
Results:
Between December 2006 and June 2013, 111 pediatric HCT patients received bimonthly IV pentamidine (574 doses, 8758 patient-days); 31 patients were younger than 2 years at initiation. In the majority (53% of courses), pentamidine was initiated because of cytopenias. Fourteen patients (12.6% of patients, 2.4% of doses) experienced a side-effect prompting discontinuation, including 3 patients with infusion-related hypotension/anaphylaxis and 3 with acute pancreatic dysfunction. No patients [0% (95% confidence interval: 0-3.2)] developed PCP during or after bimonthly IV pentamidine prophylaxis.
Conclusions:
Bimonthly IV pentamidine for PCP prophylaxis in the HCT pediatric population has comparable safety to monthly IV pentamidine and was highly effective, including in the very young. Bimonthly IV pentamidine should be considered in pediatric patients as second-line PCP prophylaxis.
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