can a man taking coumadin take viagra?
According to the Drug Interaction Checker, there were no potential interactions between Coumadin and Cialis. However, caution is advised in patients with pulmonary arterial hypertension receiving sildenafil (Viagra) and oral vitamin K antagonists like Coumadin. You can read more about the possible interactions here: Drug Interactions – Coumadin and Viagra
There are also possible interactions between each of these drugs and certain foods, which are listed in the link above.