Contraindications
Contraindications include:
Concomitant use of nitric oxide donors, organic nitrites and nitrates, such as:
nitroglycerin
isosorbide mononitrate
isosorbide dinitrate
sodium nitroprusside
alkyl nitrites (commonly known as "poppers")
Concomitant use of soluble guanylyl cyclase stimulators, such as riociguat
Known hypersensitivity to sildenafilSildenafil should not be used if sexual activity is inadvisable due to underlying cardiovascular risk factors. Nonmedical use
Recreational use
Sildenafils popularity with young adults has increased over the years. Sildenafils trade name, Viagra, is widely recognized in popular culture, and the drugs association with treating erectile dysfunction has led to its recreational use. The reasons behind such use include the belief that the drug increases libido, improves sexual performance, or permanently increases penis size. Studies on the effects of sildenafil when used recreationally are limited, but suggest it has little effect when used by those who do not have erectile dysfunction. In one study, a 25 mg dose was shown to cause no significant change in erectile quality, but did reduce the postejaculatory refractory time. This study also noted a significant placebo effect in the control group.Unprescribed recreational use of sildenafil and other PDE5 inhibitors is noted as particularly high among users of illegal drugs. Sildenafil is sometimes used to counteract the effects of other substances, often illicit. Some users mix it with methylenedioxymethamphetamine (MDMA, ecstasy), other stimulants, or opiates in an attempt to compensate for the common side effect of erectile dysfunction, a combination known as "sextasy", "rockin and rollin" or "trail mix". Mixing it with amyl nitrite, another vasodilator, is particularly dangerous and potentially fatal.
The presence of a positive pathergy reaction is not associated with an increased risk for specific mucocutaneous or systemic manifestations of the disease, and probably does not predict a more severe disease course.It is also important to note that, while a positive pathergy reaction helps to confirm a specific Behçets disease diagnosis, a negative reaction does not invalidate a BD diagnosis, because the disease process has to be active at the time of the skin prick test to produce a pathergy reaction. Differences in positive/negative pathergy and severity of the reaction depend on disease activity, ethnicity, type of needle used for the prick test, among other factors.Pathergy test is done both orally and cutaneous. Orally, the lower lip is the site of testing. Appearance of any ulcer or papule indicates a positive pathergy reaction. Cutaneous sites are the flexor forearm. Epidemiology
See also
Cutaneous conditions
List of cutaneous conditions


== References ==