Misuse of prescription medicines is as prevalent as the use of recreational drugs and novel psychoactive substances in Singapore: an unrecognised public health issue?

Introduction: Misuse of prescription medicines and the harms associated with such use are growing threats across the world. There is currently, however, limited data on the extent of prescription medicine misuse in Singapore and whether this is a current threat in the country. Methods: An online survey, limited to 1,000 individuals (aged 21 years and over) who were residents in Singapore, was administered through a survey panel company in September 2015. The survey collected information on participant demographics, and their awareness, self-reported lifetime and past-year misuse of commonly available prescription medicines in Singapore as well as the use of a range of recreational drugs and novel psychoactive substances (NPS). Results: Lifetime (6.7%) and past-year (4.8%) misuse of any prescription medicine was comparable to lifetime (6.0%) and past-year (3.0%) use of any recreational drugs/NPS. The top five prescription medicines for lifetime misuse were: diazepam (2.7%); codeine (2.3%); dhasedyl (promethazine, codeine and ephedrine; 1.6%); panadeine (paracetamol and codeine; 1.5%); and methylphenidate (1.2%). The top five drugs for past-year misuse were: diazepam (1.6%); codeine (0.9%); panadeine (0.7%); alprazolam (0.6%); baclofen (0.6%); and gabapentin (0.6%). Conclusion: Misuse of prescription medicine in Singapore was common, with prevalence comparable to the use of recreational drugs/NPS. A common source for misused drugs was physicians. Further studies are required to determine whether this is more widespread in Singapore and establish the different forms of drug diversion, so that appropriate prevention strategies can be implemented.