Prescription Medication Sharing: A Systematic Review of the Literature

Kebede A. Beyene, MSc; Janie Sheridan, PhD; Trudi Aspden, PhD

Disclosures

Am J Public Health. 2014;104(4):e15-e26. 

In This Article

Discussion

To our knowledge, ours was the first review to systematically summarize research on nonrecreational medication sharing. The reviewed literature mainly investigated medication sharing from a medical—rather than a sociological or cultural—perspective. Furthermore, most of the studies were conducted in developed countries, where access to and affordability of health care services might be different than in developing countries. Authors of the reviewed articles conducted their studies with varying aims and methods. Differences in cultures, health care systems, economics, education, and medication use behaviors across the study settings made comparing findings challenging. However, we were able to draw instructive conclusions on medicine sharing.

The extent and type of medicine regulation varied across states and countries. Whether a medicine requires a prescription or is available over the counter varies internationally.[35] Thus, we could not determine an appropriate denominator to report the average sharing prevalence for all studies. Overall, we documented high prevalence rates of medication lending (6%–22.9%) and borrowing (5%–51.9%). The studies that reported the highest rates of borrowing[22,24,26–28] or lending[22–25,27,28] were undertaken between 2008 and 2011; studies conducted before 2005 reported relatively lower rates of lending or borrowing.[1,17,19,20] This might be attributable to a general increase in self-medication with prescription medicines in recent years.[36,37]

In 6 studies, lending was generally less prevalent than borrowing,[1,17,22,23,27,28] and this could be attributable to response bias. As noted by Caviness et al., people may be more willing to admit receiving medication from others than giving (or lending) it to someone else.[10] The existence of drug vendors who offer prescription medicines without a prescription[38] is a possible explanation for the much higher rate of borrowing (51.9%) reported among Nigerian college students than borrowing rates in other studies.[28]

Similar to studies investigating recreational sharing of prescribed medications,[5,7,9] our review revealed that the most common source of shared medicines was either a family member or a friend. It is likely that participants preferred to obtain medications from trusted sources than through other channels, such as theft or prescription fraud.

Studies that examined the types of medicines shared found pain medications, allergy medications, and antibiotics to be the most commonly shared classes of medicines. In light of the addictive potential of some pain medications,[39] the possibility of adverse reactions from allergy medications,[40] and the development of bacterial resistance associated with uncontrolled use of antibiotics,[41] health care providers should take proactive measures to limit the sharing of these medicines. Sharing of medicines with high teratogenic potential, such as isotretinoin (a US Food and Drug Administration category X drug), observed among women of child-bearing age, carries a risk of birth defects, particularly if women do not inform their health care provider about their borrowing practices.[23]

Four surveys found that the odds of medication lending were higher in female than male respondents;[1,17,22,23] this might be associated with greater medication consumption by women than men,[42] or related to the nurturing role of women in many cultures.[43] The higher prevalence of sharing among younger respondents, in particular college students,[27,28] was consistent with findings in other studies on recreational sharing of medications among similar groups.[9,10] Exposure to new lifestyles at colleges might lead to both social and academic stress and ultimately to medication sharing for self-medication as a response to such stress.[44] Furthermore, a move away from home might reduce convenient access to students' usual general practitioners.

We found the association between race/ethnicity and medication sharing inconclusive. Ethnic groups across the studies were not similar; thus, it was difficult to compare findings. Moreover, access to health care services, including availability of medications, differs across countries, and this might influence sharing practices across studies.

Several studies did not explore income as a predictor of sharing behaviors. This might be because most of the studies were carried out in developed countries, where health insurance and subsidized medicines, which are relatively affordable, are available to many. However, as noted by Costello,[45] with the rising cost of health care, patients may have difficulty paying for a visit to a medical practitioner to obtain prescriptions, and they might share medicines instead.

The sharing practices documented among older people (≥ 65 years),[19,20,31] although not as prevalent as in younger age groups,[1,24,28] could result in adverse drug events.[2] Studies reported sharing of a range of pharmacological categories, such as heart disease medications, antidepressants, antihypertensives, pain medications, and antibiotics, among older people.[19,20,31] Heuberger noted that medication sharing results in polypharmacy among older people.[46] Medication sharing can have other consequences, such as a delay in seeking care,[25] which may complicate simple conditions or, in the worst-case scenario, result in death. Clinicians may be unaware of a patient's sharing practices, raising the risk of adverse medication interactions. Finally, when borrowing, the recipient may not obtain adherence aids that should accompany the medicine and thus may not comply with the medication's use instructions.

Articles that recommended interventions mainly based their proposals on research informed by a medical perspective and largely overlooked sociological or patient perspectives. Efforts to test some of the recommended interventions to minimize the harms of sharing were very limited. It is important to note that medicines are more than a chemical entity; they are an element in our social interactions, beliefs, caring relationships, moralities, and routines.[47] Practically, it might also be difficult to stop people from sharing medicines. Thus, any interventions designed to reduce potential harms of sharing need to understand and take into account why people share, how they make decisions to lend or borrow, whether they are aware of the risks, and how they assess the relevance of that risk. The latter 2 issues remain unexplored and are important areas for future research.

The laws and regulations of several countries prohibit distributing prescription medicines, in the form of gifts or loans or receiving them from a person unauthorized to dispense medicines;[48,49] however, implementation of such laws can be challenging. The regulations also lack clarity for some medicines, which can be obtained either by prescription or over the counter. For instance, in many countries paracetamol is classified as a prescription medicine or an OTC medicine depending on the pack size, formulation and labelling.

Limitations

Most of the studies in our review adopted a similar survey tool. Although this could be useful for comparing findings, a tool developed for a certain target population in a specific country might not be appropriate for assessing the sharing practices of different population groups. Furthermore, the studies did not indicate the validity and reliability of the tool in their respective settings. No gold standard method has been established for measuring the prevalence of medication sharing, and the definitions and measures of sharing varied across the studies. The use of a long recall period (≥ 1 year) for self-reported medication sharing might also have resulted in underreporting because of recall bias. We suspect also that study participants who considered medication sharing to be illegal might not have admitted to it. Bias in participant selection could also have resulted from the voluntary nature of participation. Furthermore, in an effort to identify the types of shared medicines and reasons for sharing, many of the surveys listed predetermined factors and asked the participants to choose from them; this process might limit the discovery of other motives for sharing from the patient perspective.

The majority (73.7%; 14/19) of the reviewed studies were from the United States, Australia, and New Zealand; therefore, the findings might not represent the practice of sharing in resource-limited settings. They also may not be generalizable to the larger population the study sample was meant to represent because of nonrandom sampling. Because of the heterogeneity of the articles in our review, we could not assess risk of bias across studies. Moreover, 7 surveys did not report their response rate. The cross-sectional nature of most of the studies limited understanding of cause and effect. We did not include unpublished reports, book chapters, review articles, or commentaries; thus, some relevant information might have been omitted.

Conclusions

Although sharing of prescription medicines has received limited attention from researchers, our review demonstrated that nonrecreational prescription medication sharing is common. Studies reported that broad classes of prescribed medicines were shared, and sharing was more common among younger adults and adolescents. The main circumstances for borrowing were already taking a medicine but running out of it and having the same medical problem as the person who had the medicine; motivations for lending were having leftover medication and the desire to help others.

The literature to date has mainly taken a medical perspective and largely overlooked investigating medication sharing from patients' perspectives; many gaps exist in the research. Future studies should explore medication sharing from a patient and societal perspective.

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