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QJM. 2020 Jan 1;113(1):25-30. doi: 10.1093/qjmed/hcz215.

Non-medical use of loperamide in the UK and the USA.

Author information

Clinical Toxicology Department, St Thomas' Hospital, Westminster Bridge Road London, London, UK.
Faculty of Life Sciences and Medicine, King's College London, Strand, London, London, UK.
Rocky Mountain Poison and Drug Center, 1391 Speer Boulevard, Suite 600, Denver, CO, USA.



Loperamide is a mu-opioid receptor agonist that is available as an over-the-counter anti-motility agent in the US and UK; recommended maximum doses of 12-16 mg/day. Anecdotal reports of non-medical use (NMU) have increased over the past decade with supra-therapeutic doses (70-800 mg/day) associated with cardiotoxicity. Little data exists on the prevalence of loperamide NMU.


The aim of this study was to determine the prevalence of loperamide NMU in the UK and US and to describe characteristics of non-medical loperamide users.


The Researched, Abuse, Diversion and Addiction Related Surveillance (RADARS® ) Survey of Nonmedical Use of Prescription Drugs (NMURx) was utilized to study NMU of loperamide among the adult population in the UK and US in 2017. The RADARS® NMURx is anonymous and self-administered online.


A total of 40,029 completed surveys were included (10,019 from the UK and 30,010 from the US). Respondents were asked questions about medical and NMU of loperamide, frequency of and reasons for NMU, route of use problematic drug use markers, and demographics.


Prevalence of lifetime loperamide use (95% CI) and lifetime NMU of loperamide were: UK 28.5% (27.67-29.4), and 0.66% (0.5-0.8), respectively; US 33.7% (33.1-34.2), and 5.19% (4.9-5.5), respectively. Problematic drug use markers were elevated in those who reported NMU of loperamide in both the UK and US, however high-risk use was more prevalent in the UK than in the US.


NMU of loperamide is common. In the current international environment of opioid addiction involving both therapeutic and illicit opioids, awareness of the NMU of loperamide is important.


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