By Adam J. Gess, MD
In this era of ballooning healthcare costs and decreasing sources of healthcare funding, the importance of generic medications is increasing. Generic medicines offer a way to save the healthcare system money while appropriately caring for our patients. Can we trust that the generic medicines we prescribe will treat our patients as effectively as the brand-name ones?
A review article published by Zore and colleagues in the March 2013 edition of the British Journal of Ophthalmology addresses this question. After reviewing current literature related to the issue of generic medicines, they raise some interesting points on the subject.
Generic medicines have been assuming an increasing role in our healthcare system. In 2011, generics accounted for 80 percent of prescriptions written in America. This increase is undoubtedly related to the cost savings that generics offer. A recent study found that generic drugs saved the healthcare system $192 billion in 2011 alone.
Our current system of governance regarding the use of generic drugs derives from the 1994 Uruguay Round Agreements Act, which set the patent term for a novel drug to 20 years from the first date of filling. Since drug patents are typically filed long before the drug comes to market, the practical life of patented drugs is usually much shorter than this 20-year period.
Approval and monitoring of generic medications is much less stringent than the process for new medications. A manufacturer only needs to ensure "bioequivalence," which means active ingredients, strength and dosage are the same as the original drug. However other ingredients can differ, including inactive ingredients, preservatives, the pH and the container. It has been shown that changing the bottle size alone can greatly affect the amount of medicine a patient receives from an eye drop, ranging from 25μl to 70μl.
Clinical reports have shown that the differing features of generic medications can have real effects on patient care. In the late nineties, reports of corneal toxicity related to generic diclofenac caused its manufacturer Falcon to withdraw it from the market. A follow-up study showed that the frequency of these adverse effects, which included corneal melts, returned to prior levels following the drug's withdrawal.
Other commonly used eye medications have shown reduced efficacy when administered in generic forms. Some generic prednisolone acetate versions have been found to contain smaller suspended drug particles and decreased concentrations of active drug. A study in India observed substandard concentrations of ofloxacin in 20 percent of generic forms studied.
While ophthalmologists are familiar with the differences between generic and branded medications, patients may not be. Surveys suggest that patients are often unaware that they have been given a generic medication rather than a branded one. In a study from Slovakia, two-thirds of patients were reportedly unaware if they were using a generic or branded medication.
As ophthalmologists, our role in treating patients extends beyond the point at which we hand them a prescription. We need to be aware of the implications of using generic medications, and need to appropriately convey these implications to our patients. While the cost savings to our healthcare system from generic drug use is undeniable, we must give patients the option to use brand-name medication if they feel uncomfortable with the use of generics.
An important resource for ophthalmologists concerned about generic medications is the Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the 'Orange Book.' This reference lists generic medications and gives them a grade based on available information about their bioequivalence. It can be found online through the FDA's website. While this reference source does not list all generic forms of a medication, it is an important starting point for physicians.
Ophthalmologists must continue to study the clinical efficacy of commonly used generic drugs, and keep current on new studies comparing their therapeutic efficacy. We must inform our patients about the advantages and disadvantages to generic drug use, so they can make informed decisions regarding the treatment of their ophthalmic conditions.