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Generic Drugs: More Than Meets the Eye?

Not all drugs are created equal. Be aware of these potential differences.
By Joseph P. Shovlin, OD

11/15/2015


Current concerns over prescription costs put generic drugs at the forefront of prescribing. Most patients think they have hit the jackpot if a medicine they need is available in generic form. But, have they really found a pot of gold—or are they meddling with an impostor likely to do harm?

Brand Names Don’t Last Forever
As we know, patents are awarded for approximately 20 years, depending on the country in which they are issued.1-3 While this time span may seem excessive, it takes time for the drug to go through the approval and manufacturing process. Consequently, the drug’s actual marketing or “money-making” time is reduced to an average of seven to 10 years.2 Manufacturers can extend the patent by making a “significant” formulation change, but additional trials are often necessary to re-verify the patent, bogging the process down further.

Generic Regulations
When the patent is no longer in force, the generic drug steps up to the plate. Currently, generic drugs account for nearly 80% of all prescriptions written.2 But, what scrutiny does the generic drug undergo to deem it a suitable replacement for the branded drug?

Policies and regulations for generic drugs have changed significantly over the years. Additionally, the FDA also allows for a 10% variance in active and inactive ingredients in branded drugs; the same variance is acceptable in generic versions.4 Prior to regulatory changes made in 1992, the FDA permitted generic drug manufacturers to use different inactive ingredients from the innovator drug, as long as the active ingredients were the same. This poses a problem for some medications we use today, as generics approved before 1992 were labeled the same as medications we currently use, but are not truly equivalent. Changes in tonicity and demulcents can affect retention time and alter absorption.4 A simple pH difference between generics and a brand name may affect compliance and result in detrimental long-term effects to the eye.2  

Wiley Chalmers of the FDA’s ophthalmology division notes that ointments and other non-solution dosage forms present different considerations.”4 These ophthalmic drugs can be significantly affected by different manufacturing processes, even when the active and inactive ingredients are qualitatively and quantitatively the same. Since 1992, comparative clinical trials to dispel these concerns have been implemented by FDA.1,3,4

An additional problem is the lack of bioequivalency trials required of generic drugs. Variances can occur due to differences in bottle size, shape and material; additionally, cap colors don’t have to match.3 Drop size (based on the diameter of the bottle opening) may be different among generics, and the appearance of the bottle may change from month to month. Oddly, generic manufacturers are not required to alert physicians or patients of any problems on the package insert, since the label can’t be altered from the branded innovator product.3 

Stranger in a Strange Land
Patients who shop online for generics expose themselves to even more risks. Many times, these medications are produced outside of the US. Generic drug manufacturing practices in other countries are sometimes not closely monitored. As such, a number of potential problems exist: products can have impurities, imperfect ingredient matches and even fraudulent formulations.2,3 This can lead to ineffective treatment regimens, with morbidity and vision loss. 

With the increasing frequency in which insurance providers require generic substitution for a brand name, it’s imperative that we watch for any new signs or symptoms related to generic drug use. Although generics are generally safe, effective and can provide substantial savings, I have concerns when this savings comes at the expense of drug standardization and safety. Even with revised FDA requirements that on the surface appear to be adequate, the safety and efficacy of some generic drugs remains in dispute.  

1. Mandal A: Drug patents and generic pharmaceutical drugs. News Medical, Aug., 2015.
2. Zore M, Harris A, Tobe LA, et al: Generic medications in ophthalmology. Medscape, Aug., 2015.
3. Kahook MY: Branded vs. generic: Proceed with caution. Review of Ophthalmology, April, 2015.
4. Chalmers WA: Ophthalmic generics-Are they really the same? Ophthalmology, 119:6, 2012.



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