sildenafil boosts effects of prazosin by pharmacodynamic synergism. Stay clear of or Use Alternate Drug. Risk of hypotension; separate sildenafil >25mg from alpha blocker by 4hr.istradefylline will boost the degree or effect of sildenafil by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Thankfully, many dependable onlin