The costs of developing new treatments and bringing them to the market are substantial. The pharmaceutical industry uses drug promotion to gain a competitive market share, and drive sale volumes and industry profitability. This involves disseminating information about new treatments to relevant targets. However, conflicts of interest can arise when profits are prioritised over patient care and its benefits. Drug promotion regulations are complex interventions that aim to prevent potential harm associated with these activities. To assess the effects of policies that regulate drug promotion on drug utilisation, coverage or access, healthcare utilisation, patient outcomes, adverse events and costs. We searched Epistemonikos for related reviews and their included studies. To find primary studies we searched MEDLINE, CENTRAL, Embase, EconLit, Global Index Medicus, Virtual Health Library, INRUD Bibliography, two trial registries and two sources of grey literature. All databases and sources were searched in January 2023. We planned to include studies that assessed policies regulating drug promotion to consumers, healthcare professionals or regulators and third-party payers, or any combination of these groups.In this review we defined policies as laws, rules, guidelines, codes of practice, and financial or administrative orders made by governments, non-government organisations or private insurers. One of the following outcomes had to be reported: drug utilisation, coverage or access, healthcare utilisation, patient health outcomes, any adverse effects (unintended consequences), and costs. The study had to be a randomised or non-randomised trial, an interrupted time series analysis (ITS), a repeated measures (RM) study or a controlled before-after (CBA) study. At least two review authors independently assessed eligibility for inclusion of studies. When consensus was not reached, any disagreements were discussed with a third review author. We planned to use the criteria suggested by Cochrane Effective Practice and Organisation of Care (EPOC) to assess the risk of bias of included studies. For randomised trials, non-randomised trials, and CBA studies, we planned to estimate relative effects, with 95% confidence intervals (CI). For dichotomous outcomes, we planned to report the risk ratio (RR) when possible and adjusted for baseline differences in the outcome measures. For ITS and RM, we planned to compute changes along two dimensions: change in level and change in slope. We planned to undertake a structured synthesis following EPOC guidance. MAIN RESULTS: The search yielded 4593 citations, and 13 studies were selected for full-text review. No study met the inclusion criteria. We sought to assess the effects of policies that regulate drug promotion on drug use, coverage or access, use of health services, patient outcomes, adverse events, and costs, however we did not find studies that met the review's inclusion criteria. As pharmaceutical policies that regulate drug promotion have untested effects, their impact, as well as their positive and negative influences, is currently only a matter of opinion, debate, informal or descriptive reporting. There is an urgent need to assess the effects of pharmaceutical policies that regulate drug promotion using well-conducted studies with high methodological rigour.