I'm a little confused on this, I see the combo can drop blood pressure quickly but are we saying bodybuilders never use this with a pre or intra workout product? Almost all of them have some type of nitrate in there, I also read even BCAA/EAA could do it?
You would probably be fine when mixing PDE5 inhibitors and OTC nitrates, but you also need to consider dose. For example, there is a big difference between 10 mg tadalafil + 500 mg sodium nitrate...and 100 mg sildenafil + 2,000 mg sodium nitrate. The later could potentially cause issues (potentially dangerous drop in BP, particularly if your BP is already in an ideal range).
On the other hand, I would NOT mix PDE5 inhibitors with script drugs like nitroglycerin. Nitro by itself can cause dangerous drop in BP, especially at higher dosages. Adding a PDE5 inhibitor to that could potentially spell very bad news.
In conclusion, I would not worry too much about combining OTC nitrates with PDE5 inhibitors. If the OTC product you are considering using has a very high dose of nitrates, such as MA-Pump (1,500 mg sodium nitrate), then you might want to consider using a half-dose when combining it with a PDE5 inhibitor...especially the first time you use it. From there you can make adjustments based on your personal response and needs.
Don't confuse nitroglycerin with glycerin/glycerol, which are two completely different things. Many pump products contain glycerol (HydroMax, GlycerPump, etc), while nitroglycerin is a very potent prescription nitrate that could kill you in the event of an OD.