Towards medicines reuse: a narrative review of the different therapeutic classes and dosage forms of medication waste in different countries

Background: Medicines reuse, the idea of re-dispensing returned medicines to others following quality control, is yet to be implemented in the UK. This practice is potentially a sustainable way of dealing with returned medicines, which are otherwise classed as medication waste and destroyed. To inch towards medicines reuse, it is important to know more about the different therapeutic classes and dosage forms that make up medication waste. For example, it is helpful to know if medicines being returned are mostly solid-dosage forms and thus have the potential to be reused or are from therapeutic classes that would make medicines reuse cost-effective. Little is known about the therapeutic classes and the dosage forms of wasted medicines. This study aimed to narratively review and report findings from the international literature on the different therapeutic classes and the dosage forms of medicines that are returned by patients to community pharmacies, hospitals, general practitioners’ clinics, or collected through waste campaigns. Studies based on surveys without physically returning medicines were also included where relevant. Methods: A comprehensive electronic search of databases, including PubMed and Google Scholar, was carried out over one month in 2017 and updated by 5 November 2020, using a combination of carefully created keywords. Results: Forty-five studies published in English between 2002 and 2020, comprising data from 26 countries were included and reviewed. Oral solid dosage forms (mostly tablets) were the commonly reported dosage form of all wasted medicines in 14 studies out of the 22 studies (64%) that described the dosage form, with percentages ranging from 40.6% to 95.6% of all wasted medicines. Although there was variability among the levels of medication waste reported in different countries, findings from the UK and Ethiopia were relatively consistent; in these, medicines for the cardiovascular system and anti-infective medicines, respectively, were the most common therapeutic classes for medication waste. Conclusion: This narrative review provides insights about the different therapeutic classes and dosage forms of medication waste either returned by patients, collected through waste campaigns, or indicated in survey responses. The findings could help policy makers understand the potential implications of treating most unused medicines as medication waste and whether therefore pursuing a medicines reuse scheme could be environmentally or financially logical. The quality and the safety of these returned medicines using criteria related to the storage conditions (such as heat and humidity), physical shape (such as being sealed, unopened, unused, and in blister packaging), and tampering are other important considerations for a medicines reuse scheme