For pharmacists that have dispensed generic medicine instead of a brand name prescription, it is very common to receive queries from patients about the changes in shapes and colours. By convention, a generic medicine would contain the same active ingredient in identical strength with the innovator formulation. Therefore, once a generic drug is granted its marketing license, pharmacists can assume that for the most part, there is no difference between the generic drug and the brand-name counterpart in their efficacy and safety. However, a recent study has raised doubts over the presumed equality between generic and brand-name drugs.

Drug patents affect the final appearance of a generic drug

Currently, the national and international rulings on generic drugs only dictate that the active ingredient and its related rate and extent of absorption must be comparable to the original, brand-name medication (1,2). Thus, manufacturers are given the flexibility to decide the physical appearances of their products.

However, pharmaceutical companies typically hold several patents over the same medication, such as the active ingredient, the manufacturing process, and specific formulations that altered the drug pharmacokinetic profile, and these patents usually do not expire at the same time. Due to the complicated regulations on drug patents, it is very difficult for generic drug companies to simply import an original drug formulation, including the shape and colour, into their own version without any modifications.

Pill shapes and sizes affect patient’s persistence

A research team led by Dr Aaron Kesselheim decided to look into the effects of pill shapes and sizes on the patients' persistent use of their medication. Patient persistence, in this case, was defined as the time from treatment initiation to discontinuation of therapy. They discovered that patients who received pills of different sizes and shapes were more likely to experience gaps in their treatment regimen (3).

Another study published in PLoS One supported the above findings, concluding that “patients who are first-time switchers of a specific drug were at higher risk of non-persistence compared to never switchers and those having experienced previous generic switching” (4).

Effect of patient’s persistence on outcomes unknown

Though these studies may have made headlines around the world, physicians and pharmacists should not rush to conclude that generic switching will undermine treatment efficacies. Dr Kesselheim and his team did not include clinical outcomes as part of their assessment.

In other words, it was not known if patients who were not persistent in taking their medication experienced significantly worse clinical outcomes compared to the control group as the team pointed out. It is prudent for pharmacists to consider the potential risk of non-persistence and compare it with the actual clinical impact on patients before deciding to prescribe generic medicine or brand name drugs.

Pharmacists to advise patients on the differences

More often than not, patients become confused over the altered physical appearance of their usual medications. The generic medicine concept of “an identical active ingredient but with different looks” is not prevalent in the society, and it is particularly challenging for elderly patients to understand the concept quickly. Generic drugs play a significant part in the effort to reduce healthcare costs. Pharmacists should take extra time and effort to explain the similarities and differences, as the benefits of cheaper generic drugs should not be undermined by inappropriate patient counselling.

All in all, while it is worthwhile to investigate the true impact of generic switching on the medicine consumption behaviour of the patient, it will be wise for pharmacists to look at the whole picture when deciding if such a switch is truly desirable. MIMS

Read more:
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When prescriptions kill: Doctor-shopper consumed by deadly mix of pills
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Sources:
1. Ministry of Health Malaysia. Malaysian Guidelines for the Conduct of Bioavailability and Bioequivalence Studies. Kuala Lumpur; 2000.
2. European Medicines Agency. Guideline on the investigation of bioequivalence. Guideline on the investigation of bioequivalence. London; 2010.
3. Kesselheim AS, Bykov K, Avorn J, Tong A, Doherty M, Choudhry NK. Burden of Changes in Pill Appearance for Patients Receiving Generic Cardiovascular Medications After Myocardial Infarction. Ann Intern Med. 2014 Jul 15;161(2):96.
4. Rathe J, Andersen M, Jarbøl DE, dePont Christensen R, Hallas J, Søndergaard J. Generic Switching and Non-Persistence among Medicine Users: A Combined Population-Based Questionnaire and Register Study. Timmer A, editor. PLoS One. 2015 Mar 16;10(3):e0119688.