Incidence of Dapsone-Induced Methemoglobinemia in Solid Organ Transplant Recipients
1Pharmacy, UCSF Medical Center, San Francisco, CA, 2Clinical Phamacy, UCSF School of Pharmacy, San Francisco, CA
Meeting: 2022 American Transplant Congress
Abstract number: 1658
Keywords: Adverse effects, Dosage, Infection, Pneumonia
Topic: Clinical Science » Pharmacy » 30 - Non-Organ Specific: Clinical Pharmacy/Transplant Pharmacotherapy
Session Information
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: The purpose of this study was to determine the incidence of dapsone-induced methemoglobinemia in solid organ transplant recipients.
*Methods: This was a single-center retrospective cohort study that included adult heart, kidney, liver, and lung transplant recipients from June 1, 2012 through December 31, 2019 who received dapsone for pneumocystis jiroveci pneumonia prophylaxis. Thoracic (i.e. heart and lung) transplant recipients received dapsone 50-100mg by mouth three times a week, whereas abdominal (i.e. kidney and liver) transplant recipients received 50-100mg daily. The primary outcome was to determine the incidence of methemoglobinemia. Secondary outcomes included dose of dapsone, and the time to develop methemoglobinemia after starting dapsone. Methemoglobinemia was defined as >1.5%.
*Results: A total of 357 transplant recipients received dapsone during the time period. There were 241 abdominal (kidney=145, liver=89, and liver+kidney=7) and 116 thoracic (heart=13, heart+kidney=2, heart+lung=2, and lung=99) transplant recipients. Methemoglobinemia developed in 65 (18.2%) patients (heart=2, heart+lung=2, heart+kidney=1, lung=28, kidney=15, liver=15, liver+kidney=2). Among the single organ transplants, methemoglobinemia was observed in 2/13 (15.4%) of heart, 28/99 (28.3%) lung, 15/145 (10.3%) kidney, and 15/89 (16.9%) liver recipients. There were 33 (28.4%) thoracic transplant recipients who developed methemoglobinemia compared to 32 (13.3%) who received an abdominal transplant (p<0.05). Median dapsone dose in thoracic and and abdominal transplant patients was 36.3mg/day and 100mg/day respectively. The lower dose of dapsone used in thoracic transplant recipients was associated with methemoglobinemia (p<0.05). The median time to methemoglobinemia observation was 22.5 days.
*Conclusions: Methemoglobinemia was more frequently observed in thoracic transplant recipients. The development of methemoglobinemia does not appear to be related to higher doses of dapsone. Limitations include the retrospective nature of this study, obtaining methemoglobin levels only when clinically indicated, and the potential that methemoglobin levels were evaluated more frequently in thoracic due to pulmonary symptoms than abdominal transplant recipients. Methemoglobinemia is an under recognized adverse effect of dapsone that can have significant morbidity. Judicious monitoring can facilitate early detection and avoid untoward side effects.
To cite this abstract in AMA style:
Quan D, Gordon R, Lee J, Khoshabafard D, Han A. Incidence of Dapsone-Induced Methemoglobinemia in Solid Organ Transplant Recipients [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/incidence-of-dapsone-induced-methemoglobinemia-in-solid-organ-transplant-recipients/. Accessed May 13, 2025.« Back to 2022 American Transplant Congress