Women who use drugs in Tanzania face a disproportionately high burden of HIV and mental health disorders. Despite the availability of pre-exposure prophylaxis (PrEP), uptake remains low, highlighting the need for integrated, scalable interventions that address co-occurring substance use and mental health challenges. Motivational interviewing (MI) and cognitive-behavioural approaches, such as the Common Elements Treatment Approach (CETA), show promise for enhancing HIV prevention outcomes in this population. This study presents the protocol for a pilot feasibility trial assessing the acceptability, feasibility and preliminary efficacy of MI for PrEP (MI-PrEP) and a combined CETA and MI-PrEP intervention (CETA + MI-PrEP) to improve PrEP engagement among women who use drugs in Tanzania.

This individually randomised, parallel-group pilot trial will be conducted in Dar es Salaam, Tanzania, guided by the situated Information, Motivation and Behavioral Skills model. Eligible participants are adult women who use heroin, report recent drug-related or sex-related HIV risk behaviours, are HIV-negative and exhibit symptoms of depression, anxiety or post-traumatic stress disorder. Participants are randomised to one of three arms: MI-PrEP, CETA + MI-PrEP or enhanced treatment as usual. Interventions are delivered face-to-face by trained counsellors. Feasibility and acceptability will be assessed using recruitment and retention data, surveys and qualitative interviews. Preliminary effects will be measured for PrEP initiation, symptoms of common mental disorders and substance use.

Ethical approval has been obtained from the Johns Hopkins Bloomberg School of Public Health Institutional Review Board (25580), the Muhimbili University of Health and Allied Sciences Ethics Review Committee (MUHAS-REC-12-2023-1994) and the National Health Research Ethics Committee at the National Institute for Medical Research in Tanzania (NIMR/HQ/R.8a/Vol.IX/4830). Results will be disseminated through ClinicalTrials.gov, peer-reviewed publications, conferences, presentations and research briefings to community stakeholders.

ClinicalTrials.gov ID: NCT06835751. Initially registered 14 February 2025, https://clinicaltrials.gov/study/NCT06835751, last updated 5 December 2025.