Viagra and Cialis both tend to cause stuffy noses, because they cause engorgement of the sinus tissues with blood, just as they do for the penis. Nasal sprays such as NeoSynephrine or 4-Way (or others with the same active ingedients) will immediately relieve the stuffiness. However, use the spray sparingly, because over-use can make the nasal symptoms worse. Further, too much of the spray can actully reduce the effect of the pill on your penis. So don't use the spray until you need it, and then use the minimum necessary.