TY - JOUR VL - 36 SP - 250 N1 - This version is the author-accepted manuscript. For information on re-use, please refer to the publisher?s terms and conditions. IS - 3 SN - 0956-4624 UR - https://doi.org/10.1177/09564624241298983 A1 - Ismail, Muhammad Azam A1 - Tittle, Victoria A1 - Jones, Rachael A1 - Loftus, Hannah A1 - Girometti, Nicolo A1 - Dosekun, Olamide A1 - Stegmann, Katrina A1 - Pool, Erica A1 - Tariq, Shema A1 - Nakamura, Anna A1 - Tyler, Stephanie A1 - Coleman, Harry A1 - Teh, Yee Suh A1 - Boffito, Marta JF - International Journal of STD and AIDS EP - 254 AV - public Y1 - 2025/03// TI - Therapeutic drug monitoring of tenofovir disoproxil and emtricitabine in oral HIV pre-exposure prophylaxis (PrEP) users who have undergone gastrointestinal surgery PB - Royal Society of Medicine Press ID - discovery10206201 N2 - Objectives: Oral HIV pre-exposure prophylaxis (PrEP) is highly effective in preventing HIV, but its efficacy depends on adequate absorption of drug, which may decrease following gastrointestinal surgery.// Methods: Clinicians across eight Genito-urinary Medicine clinics in the United Kingdom submitted data on PrEP users with history of gastrointestinal surgery who were referred to a national complex PrEP multi-disciplinary team between June 2021 and April 2023. Anonymised data were submitted on demographics, surgical history, PrEP regimen, and results of therapeutic drug monitoring (TDM) and HIV screening tests. Descriptive analyses were performed in SPSS version 29.// Results: Nine cases described cis-gender men-who-have-sex-with-men (MSM) with median age of 47.4 years (IQR = 43 ? 56.5) taking tenofovir disoproxil (TDF)/emtricitabine (FTC) daily (n = 8) or event-based (n = 1) as PrEP. Median time between PrEP initiation and TDM was 53 days (IQR = 8.5?1705). The mean (ąSD) trough concentration of tenofovir (TFV) and FTC were 90.2 ą 27.7 ng/mL and 76.0 ą 45.9 ng/mL, respectively. All patients had a negative HIV test at follow-up.// Conclusions: Plasma trough concentrations of TFV observed in our cohort taking TDF/FTC were above the expected concentrations associated with PrEP efficacy as previously described in the literature, suggesting that PrEP can be safely given in this population, with TDM used for reassurance. KW - Pre-exposure prophylaxis KW - therapeutic drug monitoring KW - HIV KW - gastrointestinal surgery ER -