holy crap, that’s insane. You don’t just accidentally add sildenafil or tadalafil to your supplements. Unless the FDA is misidentifying compounds present in the herbs in these supplements, which seems unlikely but I’m no pharmacology expert.
With the amount of mislabelled product out there in circulation (and presumably a general lack of harm), does it still make sense to require a prescription?
I mean, even though 50% of these are intentional overdoses... the other 50% probably didn't know they were doing something that was going to destroy their liver: https://www.ncbi.nlm.nih.gov/books/NBK441917/
The interaction with other blood pressure meds appears additive rather than synergistic and Viagra alone only minimally reduced blood pressure. The cough and cold aisle or a cafe presents more dangers.
https://pubmed.ncbi.nlm.nih.gov/10078539/
At least over the counter Viagra would be properly labelled about these things.
It's a better regulated industry now, but with the explosion in supplement popularity over the last decade I doubt there is an easy way to test and punish all manufacturers. If you look at the list of supplements included in that warning letter, they have classic nonsensical names that Chinese companies are known for (WeFun, Genergy, etc). None are on www.amazon.com anymore, but hundreds of other supplements show up with absolutely no way of telling whether any of them are clean (e.g. "Endurance 2Nite").