What will happen if I plan on having intercourse, take Viagra and then end up not having intercourse due to some unfortunate reason? Would I have any problems?
No, you shouldn't have any problem at all. Some men even take a low dose of Viagra every day and have no difficulties.
In a situation like that, where your plans are foiled, the worst you might experience is an erection that is embarrassingly easy to get and hard to lose. You definitely won't feel any compulsion to have sex, however, since Viagra works only on the plumbing and doesn't create or enhance sexual desire.
Unfortunately, there's no way to remove the Viagra from your system. The best you can do is keep your mind off of sex in order to keep yourself in a relaxed state.
Since you should take Viagra 30-90 minutes before sex, situations like this are probably going to be unavoidable for many men. This is another reason why we recommend you try the drug by yourself first so you get a sense of how it affects you and how long it takes to act.