TY - JOUR T1 - Failure of on-demand pre-exposure prophylaxis: the risk of HIV drug resistance JF - Sexually Transmitted Infections JO - Sex Transm Infect SP - 234 LP - 234 DO - 10.1136/sextrans-2021-055354 VL - 98 IS - 3 AU - Angelo Roberto Raccagni AU - Elena Bruzzesi AU - Nicola Gianotti AU - Michela Sampaolo AU - Diana Canetti AU - Antonella Castagna AU - Silvia Nozza Y1 - 2022/05/01 UR - http://sti.bmj.com/content/98/3/234.abstract N2 - Dear Editor,A man aged 32 years who self-described as men who have sex with men (MSM) started on-demand pre-exposure prophylaxis (PrEP) with emtricitabine/tenofovir (FTC/TDF) based on reporting 30 partners within the last 24 weeks, not using condoms in 50% of sex acts, use of gamma-hydroxybutyric acid during sex and previous STI diagnoses (Smith score=37).1 Over 1 year, we conducted 3-monthly STI screening and HIV-RNA testing. He tested HIV-negative at months 0, 3, 6 and 9. At month 12, he reported missing a single PrEP dose 1 month earlier due to gamma-hydroxybutyric … ER -