Prescription medication sharing: a systematic review of the literature.

We reviewed the literature on nonrecreational prescription medication sharing. We searched PubMed, EMBASE, PsycINFO, and a customized multidatabase for all relevant articles published through 2013; our final sample comprised 19 studies from 9 countries with 36 182 participants, ranging in age from children to older adults, and published between 1990 and 2011. The prevalence rate for borrowing someone's prescription medication was 5% to 51.9% and for lending prescription medication to someone else was 6% to 22.9%. A wide range of medicines were shared between family members, friends, and acquaintances. Sharing of many classes of prescription medication was common. Further research should explore why people share, how they decide to lend or borrow, whether they are aware of the risks, and how they assess the relevance of those risks.