Why I Sometimes Insist on Brand Name Drugs and Disallow Generic Substitutions

Ever wonder why doctors sometimes recommend a name brand prescription drug over a cheaper generic? And does it seem like your optometrist or ophthalmologist tends to do so more often? There’s a reason for both.

With the cost of drugs ever on the rise, patients understandably request from me or their pharmacist the generic versions of the drugs I prescribe. In Texas, pharmacists are allowed to substitute generic meds – that is, unless the physician writes the prescription in such a way that substitutions aren’t allowed. I sometimes do this, and patients don’t always understand why. They think the only difference between name brand and generic is the label. That’s incorrect.

When new generic medications are introduced, physicians must read up on their therapeutic efficacy and safety. We ask, “Are generic medications as effective as their brand name counterpart? And are there any potential negative outcomes from generic medications?”

Eye doctors in particular are up against a difficult challenge when evaluating the efficacy of ocular generic medications, and that’s due to the way the drugs are administered. In order for an orally administered generic medication to gain FDA approval, it must be “bioequivalent” to its brand name counterpart. Essentially, that means it works in the body the same way. It does not mean identical in chemical composition. When blood plasma levels are compared, generic medications are allowed to be 15 percent lower or 25 percent higher. There are no such thresholds or measurements for ophthalmic medication instilled in the eyes. Instead, the FDA requires that the generic med itself have the same concentration of the active ingredient the brand name contains. The FDA does not necessarily consider whether the generic acts the same way in the body. That’s my job.

It takes a vehicle (i.e., other ingredients) to transport the active ingredient to the area of need. In generic medication, it’s the vehicle that is different. And sometimes, it acts differently or is not as effective. Further complicating things, which vehicle works best can vary from one patient to another.

When I evaluate the safety and efficacy of a generic ocular medication, I consider whether the vehicle delivers the goods the way it needs to so the patient sees the full benefit. Simply put, a generic derivative is not always as effective as the brand medication, in which case I will switch a patient back to the brand medication. Yes, it costs more. But when I tell patients a generic is not best for them, it’s for reasons concerning their health, which I will always safeguard before finances.

Dr. Jeff Pinkerton
I care for you.