["Criminal Behaviour and Mental Health, Volume 31, Issue 2, Page 131-142, April 2021. ", "\nAbstract\n\nBackground\nThe widespread use of drugs in prisons leads to avoidable deaths, poorer health and a poor living environment. The contribution of psychoactive prescription drugs to this problem has received little attention in prison policy or at individual prescriber level.\n\n\nAims\nTo determine the extent of unsafe and inappropriate prescribing of psychoactive medications in one UK prison using a newly developed medicines optimisation framework.\n\n\nMethod\nA medicines optimisation framework was developed based on principles of good prescribing. It was initiated on the opening of a new prison—HMP Berwyn—in February 2017. During the study period, all prisoners at HMP Berwyn were transferred from other prisons. The safety and appropriateness of psychoactive medications were evaluated de novo on reception at HMP Berwyn and during follow up, using the medicines optimisation framework.\n\n\nResults\nAbout 1941 sentenced men arrived at HMP Berwyn between February 2017 and November 2018. Nearly one‐third (634, 33%) were on a prescribed psychoactive medication. Seventy‐five percent of these (474/634) required a prescription change due to appropriateness or safety concerns. Nearly half (295, 46.5%) received changes at reception despite having already undergone medicines reconciliation at their previous prison. Forty‐three percent (275/634) received changes at follow up, most commonly those who had no prior risks identified at reception.\n\n\nConclusions\nInappropriate and unsafe prescribing of psychoactive medications is occurring in prisons despite mandatory medication reviews. Ongoing monitoring is required to reduce the risk from these medications. A medicines optimisation framework such as this could be adopted across other prisons, worldwide, to help contribute to risk reduction from drug use in prisons. Appropriately modified, a similar framework might help reduce inappropriate and harmful prescribing in hospitals and in the community.\n\n"]