eprintid: 10206201 rev_number: 8 eprint_status: archive userid: 699 dir: disk0/10/20/62/01 datestamp: 2025-03-18 09:56:07 lastmod: 2025-03-18 09:56:07 status_changed: 2025-03-18 09:56:07 type: article metadata_visibility: show sword_depositor: 699 creators_name: Ismail, Muhammad Azam creators_name: Tittle, Victoria creators_name: Jones, Rachael creators_name: Loftus, Hannah creators_name: Girometti, Nicolo creators_name: Dosekun, Olamide creators_name: Stegmann, Katrina creators_name: Pool, Erica creators_name: Tariq, Shema creators_name: Nakamura, Anna creators_name: Tyler, Stephanie creators_name: Coleman, Harry creators_name: Teh, Yee Suh creators_name: Boffito, Marta title: Therapeutic drug monitoring of tenofovir disoproxil and emtricitabine in oral HIV pre-exposure prophylaxis (PrEP) users who have undergone gastrointestinal surgery ispublished: pub divisions: UCL divisions: B02 divisions: D01 keywords: Pre-exposure prophylaxis, therapeutic drug monitoring, HIV, gastrointestinal surgery note: This version is the author-accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: 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 (±SD) trough concentration of tenofovir (TFV) and FTC were 90.2 ± 27.7 ng/mL and 76.0 ± 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. date: 2025-03 date_type: published publisher: Royal Society of Medicine Press official_url: https://doi.org/10.1177/09564624241298983 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2335073 doi: 10.1177/09564624241298983 medium: Print-Electronic lyricists_name: Pool, Erica lyricists_name: Tariq, Shema lyricists_id: ERMPO69 lyricists_id: STARI14 actors_name: Tariq, Shema actors_id: STARI14 actors_role: owner full_text_status: public publication: International Journal of STD and AIDS volume: 36 number: 3 pagerange: 250-254 event_location: England issn: 0956-4624 citation: Ismail, Muhammad Azam; Tittle, Victoria; Jones, Rachael; Loftus, Hannah; Girometti, Nicolo; Dosekun, Olamide; Stegmann, Katrina; ... Boffito, Marta; + view all <#> Ismail, Muhammad Azam; Tittle, Victoria; Jones, Rachael; Loftus, Hannah; Girometti, Nicolo; Dosekun, Olamide; Stegmann, Katrina; Pool, Erica; Tariq, Shema; Nakamura, Anna; Tyler, Stephanie; Coleman, Harry; Teh, Yee Suh; Boffito, Marta; - view fewer <#> (2025) Therapeutic drug monitoring of tenofovir disoproxil and emtricitabine in oral HIV pre-exposure prophylaxis (PrEP) users who have undergone gastrointestinal surgery. International Journal of STD and AIDS , 36 (3) pp. 250-254. 10.1177/09564624241298983 <https://doi.org/10.1177/09564624241298983>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10206201/1/Main%20Body%20TDM%20Paper%20Revised%20v1.1.pdf