Doctors have long thought it dangerous to prescribe erectile dysfunction drugs like Viagra alongside chest pain pills containing nitrates. Now, a new study indicates there might be little to no potential risk in co-prescribing the two types of drugs. Men are not more likely to suffer a heart attack, stroke or cardiac arrest if they've been prescribed both an ED drug and a nitrate medication, according to a study. Nitrates often are prescribed to men with heart problems and clogged arteries. In the movies, nitrates are the little pills that guys pop under their tongues when they think they might...