There must be multiple interactions and multiple charts.
Do a google search for 'drug interactions' There are a zillion sites to look at.
If you are interested in a particular OTC drug, a google search will send you to various medical sites that will tell you all about your drug.
Yes agnespuffin that was the point of my question i.e. Google has a zillion sites, hence a search for a chart.
There is a PDR for OTC drugs which might be useful. I usually search "drug name_______ side effects". I don't think you'll find a neat and tidy chart. PDR is Physicians Desk Reference. There is one given to doctors for prescription drugs. It comes out every year and is quite an eye opener.
No, you won't find a chart that will list even a small part of them.
I have found this site very useful.
Here is a link that might be useful: Drug listings
Here was the situation. An old lady in the neighborhood keeps showing up at the urgent care clinic with low blood pressure. She has been deemed not sufficiently crazy for any sort of forced commitment.
Someone giving her a ride asked to use the bathroom and counted 42 bottles of OTCs. We don't know if there is any connection to her low blood pressure or her craziness.
Check this link - prescription drugs
Here is a link that might be useful: Medicine Online Shop