I just bumped into this article and i thought i should share.

Viagra is the trade name for the drug sildenafil citrate. It works by relaxing the smooth muscle lining of certain blood vessels, causing them to expand and fill with blood. In males, this typically results in penile erection. The use of Viagra can cause side effects affecting multiple organ systems in the body.
Additionally, long-term use of this drug can potentially increase the risk of psychological dependency.
SENSORY
Long-term use of Viagra has been associated with various problems affecting the auditory (hearing) and visual systems. Loss or decrease of hearing have been reported in association with use of Viagra. An article published on Newsinferno.com (Oct 2007), cited reports of hearing loss cases in patients taking Viagra prompted the Food and Drug Administration (FDA) to add this serious side effect on the warning labels. Long-term use of Viagra can also increase the risks for double vision and temporary vision loss. Dailymed, an online site providing information on FDA approved drugs by the National Library of Medicine, cited retinal hemorrhaging and vascular diseases as potentially serious side effects of Viagra.

CEREBROVASCULAR AND CARDIOVASCULAR
Short-term serious side effects of Viagra are strokes and heart attacks. Vascular side effects are seen in long term users of Viagra, such as, cerebrovascular hemorrhage and Transient Ischemic Attack (TIA). Cardiomyopathy (enlarged heart), arrhythmia (irregular heartbeat), and heart palpitations have been reported. An article published in The Journal of Medical Case Reports, by researcher Jeppe G Rasmussen, concluded that heart arrythmias like ventricular tachycardia can potentially be an adverse effect of the drug.

GASTRO-INTESTINAL AND GENITO-URINARY SYSTEMS
Viagra affects the gastro-intestinal (GI) tract and the genito-urinary tract (GU). Long-term use can increase the frequencies of dyspepsia and intestinal problems, such as, diarrhea and gastritis. The American College of Cardiology/American Heart Association (ACC/AHA) Expert Consensus Document published in Circulation, (AHA, Journals), 1999, cited the adverse effects of Viagra's gastro-intestinal problems, such as dyspepsia and reflux, can be attributed to the relaxation of the esophageal sphincter located between the stomach and the duodenum.

Additional side effects can include issues relating to urinary tract functions, for example, incontinence, increase risk for urinary tract infections, and cystitis. Some reports of anorgasmia or the inability to ejaculate, including abnormal ejaculation, have been documented. Drugs.com cited some casual relationship between Viagra use and anorgasmia in less than 2 percent of patients on viagra clinical trials.PSYCHOLOGICAL DEPENDENCY
Long-term Viagra use can increase the potential to develop psychological dependency. An article published on Biopsychiatry.com, dated April 2004, in the Anchorage Daily News, cited that men who do not have erectile dysfunction problems are taking the drug for recreational purposes and are at risk for developing psychological dependency for the medication.