Generic drugs are often cheaper than their brand-name equivalents despite having the same efficacy, helping the US healthcare system to save USD1.68 trillion from 2005 to 2014. However, according to the Generic Pharmaceutical Association (GPhA), more can be done to maintain the cost savings associated with drugs.

One way is to pay attention to the drug design of generic drugs. Many factors of drug design affect its efficacy; the formulation affects the pattern of release, which plays a role in achieving a desired therapeutic objective; the shape may affect the mechanism of action; the size and form affects patient compliance and safety when taking the drug.

However, studies in the past few years, suggest the efficacy of generic pharmaceuticals can be optimised when they are aesthetically similar to their brand-name counterparts. Colour, especially, is regarded as critical to enhancing patient acceptance and adherence.

Pill colour may provide placebo effect

Pill colour has been found to affect the perception of its efficacy, which could give rise to placebo effects that enhance or work against the drug’s purpose. In general, drugs work best when their colour matches the intended outcome.

In the largest study of its kind involving over 10, 000 patients hospitalised for heart attacks between 2006 and 2011, researchers from the Brigham and Women’s Hospital in Boston found that when patients received a different form of their drug prescription during a refill, there was a significant effect. Patients would either stop taking the drug or avoid refilling the prescription in the future – 34% for a change in pill colour and 66% for shape.

Likewise in another study involving nearly 100 patients with epilepsy, it was found that patients exhibit marked preferences for certain pill colours over others - the colours white and yellow were much preferred over grey, caramel, and maroon.

Cooler colours like blue and green were associated with sedative and anti-anxiety effects, fiery colours like red and orange are ideal for stimulants, yellow antidepressant pills seem the most effective, and white appears to soothe pain.

The brighter the colour or the more similar it is to the brand-name equivalent, the stronger the effects. The effects of pill colour also vary across culture – for Italian men, the colour blue is stimulating rather than sedating, possibly due to it being the colour of the national soccer team.

Aesthetic consistency leads to higher patient adherence

Pill colour and shape consistency also aids in drug recognition, preventing drug mix-ups during production, packaging and dispensing. It is also usually the main way patients can differentiate drugs, preventing accidental overdoses or missing out on certain medications.

The lack of aesthetic consistency - especially in generic drugs - will also affect those who are in any way impaired (visually, mentally or otherwise) from risking confusing one medication for another. The elderly, who often are not only on multiple drugs but also suffer from other medical complications like macular degeneration or dementia, are the most affected. An unfamiliar form of prescription gives the patient reason to doubt the drug, which in turn decreases patient adherence.

“Given such strong colour preference observed in our study, it is likely that pill colour has the potential to affect patient adherence to taking medications at home, as well as subject adherence in clinical trials, and deserves further attention and study—especially for preferences specific to special patient populations,” said Dr Tricia Ting, MD, associate professor in the Department of Neurology at the University of Maryland School of Medicine, who led the epilepsy study. MIMS

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