There have been rare reports of priapism (prolonged and painful erections lasting six or more hours) with the use of PDE5 inhibitors. Patients with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Untreated priapism can cause injury to the penis and lead to permanent impotence. Therefore, if your erection lasts four hours, you should seek emergency care.
…have traditionally been classified as impotence (inability of a man to achieve or maintain penile erection) and frigidity (inability of a woman to achieve arousal or orgasm during sexual intercourse). Because these terms—impotence and frigidity—have developed pejorative and misleading connotations, they are no longer used as scientific classifications, having been…
This is similar to magnetic resonance imaging. Magnetic resonance angiography uses magnetic fields and radio waves to provide detailed images of the blood vessels. Doctors may inject a "contrast agent" into the person's bloodstream that causes vascular tissues to stand out against other tissues. The contrast agent provides for enhanced information regarding blood supply and vascular anomalies.
Your healthcare provider will ask about your symptoms, medical history, and medicines. He or she will examine your abdomen, penis, and testicles. A rectal exam may also be done to check for an enlarged prostate. Blood and urine tests are done to check for medical conditions that may have caused your ED. You may also need tests to check your blood flow and nerve function.
Injection therapy: The modern age of such drug therapies began in 1993 when the injection of papaverine (Pavabid), an alpha-blocker that produces vasodilatation (widening of the blood vessels), was shown to produce erections when injected directly into the penis. Soon afterward, other vasodilators, such as prostaglandin E1 (PGE 1) monotherapy (Caverject, Edex), PGE1 and phentolamine (Regitine), and Trimix (papaverine, phentolamine and prostaglandin E1), were demonstrated to be effective. The benefit of combination therapy is the decreased dosing of each with less side effects. Most important is the reduction of the prostaglandin PGE1 dosing, which is associated to the localized pain.
In a prospective study from the Prostate Cancer Prevention Trial database, Thompson et al reported that men presenting with ED had a significantly higher chance of developing a cardiovascular event over a 7-year follow-up period.  The hazard ratio was 1.45, which is in the range of risk associated with current smoking or a family history of MI.
In rare cases, the drug Viagra ® can cause blue-green shading to vision that lasts for a short time. In rare cases, the drug Cialis® can cause or increase back pain or aching muscles in the back. In most cases, the side effects are linked to PDE5 inhibitor effects on other tissues in the body, meaning they are working to increase blood flow to your penis and at the same time impacting other vascular tissues in your body. These are not ‘allergic reactions'.