With healthcare costs continuing to rise, generic drugs are looking more attractive than ever. The prospect of getting the same drug at a lower cost is tempting to anyone with a large drug bill — patient or insurer alike. The savings are massive: Lipitor lost patent protection last month — it was a $10 billion drug, and the generic versions are priced at a fraction of the original cost. In 2012, Plavix and Seroquel, two other blockbusters, will lose patent protection too — that’s another $10 billion in drug costs that will shrink. This “patent cliff” will shrivel about $255 billion in worldwide patented drug sales over the next five years. If you’re taking a prescription drug and not already on a generic, you probably will be soon. And depending on where you live, you may be automatically switched to a generic version of your prescription drug as soon as it’s available.
Pharmacists are responsible for most of the switches from brand to generic drugs. In Ontario, where I work, regulations specify which drugs and brands may be automatically substituted — that is, without patient or prescriber consent. This doesn’t mean a lack of transparency, however, so I spend a lot of time speaking with patients about generic drugs. Misconceptions are common, ranging from manufacturing standards (“they’re weaker!”) to efficacy (“the drugs don’t work!”). I’ve seen a number of questions and comments about generic drugs in the comments section here at SBM as well. So today’s post is an overview of the science of evaluating generic drugs. Specifically, I want to review the concept of bioequivalence, the confirmation of which assures us of the interchangeability of different drugs — that is, one can be substituted for another. (more…)