Hojilla JC, et al. - Among 400 participants, the associations of confirmed cocaine use with adherence to HIV pre-exposure prophylaxis (PrEP), care engagement, and renal function were investigated in the iPrEx open-label extension. Analyzing scalp hair samples, cocaine use was measured and categorized as light (500-3,000 pg/mg) and moderate to heavy (>3,000 pg/mg). Plasma tenofovir concentrations were determined to measure PrEP adherence in the first 3 months. Outcomes revealed decreased PrEP adherence and care engagement in correlation to cocaine use. This emphasizes the necessity for comprehensive approaches to reduce cocaine use and enhance engagement in PrEP care.