Hey ho...
I wrote earlier...
‘For those that wing it with these things, whacking the heartburn with ranitidine is usually effective.’
In case it’s not obvious, if you do this it makes sense, if you normally take the sildenafil (viagra) an hour before your punt, to take the ranitidine immediately before the punt. (If you took them at the same time then it seems likely that ranitidine will slow down the absorption of sildenafil, the same as food will.)
If you take paracetamol to stop a headache (if you get headaches from sildenafil) then it’s fine to take them together. Paracetamol doesn’t interfere with absorption of the sildenafil.
As for stuffy nose, it’s less clear whether OTC meds to treat stuffy nose would affect the sildenafil. I’d say put up with it (you may even find you get acclimatised to it).
These comments are based on experimentation/observation and the straightforward theory of how the drugs work — if anyone has any more specific pharmacological evidence to hand, do please post.