here you can buy generic viagra and get bonuses viagra online without prescription None of these PDE inhibitors should be used more than once a day. Men who take nitrate-based drugs such as nitroglycerin for heart problems should not use either drug because the combination can cause a sudden drop in blood pressure. Also, tell your doctor if you take any drugs called alpha-blockers, which are used to treat prostate enlargement or high blood pressure. Your doctor may need to adjust your ED prescription. Taking a PDE inhibitor and an alpha-blocker at the same time (within 4 hours) can cause a sudden drop in blood pressure. Increased LH Increased FSH Hyperprolactinemia Decreased libido; galactorrhea; visual complaints; headache Bitemporal hemianopsia Elevated prolactin And because impotence -- erectile dysfunction -- manifests itself two to three years sooner than coronary artery disease, the condition essentially serves as a "sentinel of the heart" -- or early warning system for cardiac trouble, a new Italian study found. Erectile dysfunction (ED) is the repeated inability to get or keep an erection firm enough for sexual intercourse. Information from references 5, 6 and 7.