Why Aren’t We More Focused On Rx-OTC Interactions?

The pharmacy system in the US does a good job of catching drug-drug interactions at the POS (point-of-sale) when the claims are all processed by a PBM or all the drugs are filled within the same pharmacy.  But, with 68% of adults taking both a prescription drug and either an OTC (over-the-counter) or dietary supplement (per JAMA Jan 2009), do we need a broader safety net to catch all those?

I was looking at an old Medco deck from last year.  It estimated that there are 30B combinations if you look at 80,000 prescription doses, 300,000 OTC products, and 75,000 dietary supplements. 

Of course, when you go to the pharmacy, you fill out some basic information.  You do the same at your physician.  But, how often are those updated?  Do you have an easy way to register new products you’re trying? 

On the flipside, the question is what percentage of these 30B combinations are important versus just noise?

There are some significant examples here…

For example, Proton Pump Inhibitors (PPIs) increase the risk of major cardiovascular events by more than 50% for patients taking Plavix, but you can now buy several PPIs over-the-counter.  How would the pharmacy or PBM know?