July 19, 2017
As some of you know I underwent bilateral knee replacements last December. It has been a really interesting experience and in the future you will hear more about it but today I want to write a little about my experience with generic drugs. In medical school we have been taught that generic drugs, with some exceptions (thyroid hormone replacement, warfarin, phenytoin) are pretty much just as good as brand name drugs. I believed them. I have said so many times to my patients. I was wrong.
After surgery I was prescribed tramadol for pain control. It is a good drug. It does its job and its side effect profile is ok. I was prescribed 100 mg of tramadol 4 times a day. I was getting my prescriptions from my local CVS(in Miami ) and everything was going well. The generic version of tramadol that I was given was working as intended. Three months after surgery I went back to work and I had my tramadol prescription filled at the local pharmacy in the town where I am currently working in rural Virginia. That pharmacy gave me a different manufacturer’s version of tramadol. I took my first dose of 100 mg and I felt HORRIBLE, sedated and having a difficult time functioning. Nothing like I was feeling with the original pill. I had to cut my dose in half.
So it turns out that the FDA in order to let a manufacturer create a generic version of a drug, the drug has to be ” identical or bioequivalent, to a brand-name drug in dosage, form, safety, strength, route of administration, quality, performance characteristics , and intended use” and the FDA requires that the 90% confidence interval of these properties fall within 80% to 125% range of the brand name medication.
In English, because I was taking two different versions of generic tramadol, they could vary in potency the equivalent of 80 mg of Ultram to 125 mg of Ultram (Ultram is the brand name of tramadol). IT SUCKED.
So having eaten my words, I promised to myself to be WAY more understanding when my patients complain that the generic pill does not work as well as the brand name.
Joaquin Barbara MD