Erectile dysfunction (ED), also referred to as impotence, is a form of sexual dysfunction in males characterized by the persistent or recurring inability to achieve or maintain a penile erection with sufficient rigidity and duration for satisfactory sexual activity. It is the most common sexual problem in males and can cause psychological distress due to its impact on self-image and sexual relationships.
Sildenafil, sold under the brand name Viagra, among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. It is also sometimes used off-label for the treatment of certain symptoms in secondary Raynaud's phenomenon. It is unclear if it is effective for treating sexual dysfunction in females. It can be taken orally, intravenously, or through the sublingual route. Onset when taken orally is typically within twenty minutes and lasts for about two hours.
Tadalafil, sold under the brand name Cialis among others, is a medication used to treat erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension. It is taken by mouth. Onset is typically within half an hour and the duration is up to 36 hours.
Vardenafil, sold under the brand name Levitra among others, is a medication that is used for treating erectile dysfunction. It is a PDE5 inhibitor. It is taken by mouth.
Yohimbine, also known as quebrachine, is an indole alkaloid derived from the bark of the African tree Pausinystalia johimbe; also from the bark of the unrelated South American tree Aspidosperma quebracho-blanco. Yohimbine is an α2-adrenergic receptor antagonist, and has been used in a variety of research projects. It is a veterinary drug used to reverse sedation in dogs and deer.
Sibutramine, formerly sold under the brand name Meridia among others, is an appetite suppressant which has been discontinued in many countries. It works as a serotonin–norepinephrine reuptake inhibitor similar to a tricyclic antidepressant. Until 2010, it was widely marketed and prescribed as an adjunct in the treatment of obesity along with diet and exercise. It has been associated with increased cardiovascular diseases and strokes and has been withdrawn from the market in 2010 in several countries and regions including Australia, Canada, China, the European Union, Hong Kong, India, Mexico, New Zealand, the Philippines, Thailand, the United Kingdom, and the United States. However, the drug remains available in some countries.
A phosphodiesterase type 5 inhibitor is a vasodilating drug that works by blocking the degradative action of cGMP-specific phosphodiesterase type 5 (PDE5) on cyclic GMP in the smooth muscle cells lining the blood vessels supplying various tissues. These drugs dilate the corpora cavernosa of the penis, facilitating erection with sexual stimulation, and are used in the treatment of erectile dysfunction (ED). Sildenafil was the first effective oral treatment available for ED. Because PDE5 is also present in the smooth muscle of the walls of the arterioles within the lungs, two PDE5 inhibitors, sildenafil and tadalafil, are FDA-approved for the treatment of pulmonary hypertension. As of 2019, the wider cardiovascular benefits of PDE5 inhibitors are being appreciated.
Cyclic guanosine monophosphate-specific phosphodiesterase type 5 is an enzyme from the phosphodiesterase class. It is found in various tissues, most prominently the corpus cavernosum and the retina. It has also been recently discovered to play a vital role in the cardiovascular system.
Herbal viagra is a herbal product advertised as treating erectile dysfunction. Many different products are advertised as herbal viagra, but with varying ingredients. No clinical trials or scientific studies support the effectiveness of any of these ingredients for the treatment of erectile dysfunction and some products have been found to contain drugs and other adulterants, and have been the subject of FDA and FTC warnings and actions to remove them from the market.
Acetildenafil (hongdenafil) is a synthetic drug which acts as a phosphodiesterase inhibitor. It is an analog of sildenafil (Viagra) which has been detected in numerous different brands of "herbal aphrodisiac" products sold in convenience stores that claim to boost libido and alleviate erectile dysfunction.
AC-262536 is a drug developed by Acadia Pharmaceuticals which acts as a selective androgen receptor modulator (SARM). Chemically it possesses endo-exo isomerism, with the endo form being the active form. It acts as a partial agonist for the androgen receptor with a Ki of 5 nM, and no significant affinity for any other receptors tested. In animal studies it produced a maximal effect of around 66% of the levator ani muscle weight increase of testosterone, but only around 27% of its maximal effect on prostate gland weight. It is an aniline SARM related to ACP-105 and vosilasarm (RAD140).
ABT-202 is a drug developed by Abbott, which acts as an agonist at neural nicotinic acetylcholine receptors and has been researched for use as an analgesic, although it has not passed clinical trials.
Sulfoaildenafil (thioaildenafil) is a synthetic drug that is a structural analog of sildenafil (Viagra). It was first reported in 2005, and it is not approved by any health regulation agency. Like sildenafil, sulfoaildenafil is a phosphodiesterase type 5 inhibitor.
Nitrosoprodenafil is a synthetic designer drug found in "herbal" aphrodisiac products, which is a novel nitrosated analogue of sildenafil (Viagra). It has an innovative structure which acts as a prodrug, breaking down in the body to release both the PDE5 inhibitor aildenafil as well as free nitric oxide, which have powerfully synergistic effects. This dual mechanism of action has never been exploited by conventional pharmaceutical companies because of the risks involved; usually combining PDE5 inhibitors with nitric oxide releasers like amyl nitrite is contraindicated as it can cause a precipitous drop in blood pressure that can potentially result in death. Nitrosamines are also generally avoided in drug development as they can often be hepatotoxic and carcinogenic, so while the combined mechanisms of action are likely to be effective, this drug also has severe risks of toxicity.
N,α-Diethylphenethylamine is a close chemical analog of methamphetamine, which has been sold as a designer drug. It was originally patented by Knoll Pharma as one of several analogs for pharmaceutical applications. In animal models these analogs showed properties of cognitive enhancement and increased pain tolerance. Nevertheless, this class of compounds was never developed into a medicine. N,α-DEPEA has not been studied in humans, but experts such as Pieter Cohen of Harvard Medical School expect it to be less potent than methamphetamine, but greater than ephedrine.
Benzamidenafil or xanthoanthrafil is a synthetic drug that acts as a PDE5 inhibitor. It has the same mechanism of action as pharmaceutical drugs used to treat erectile dysfunction, but it is not approved by any regulatory agency for such use.
Homosildenafil is a synthetic drug which acts as a phosphodiesterase inhibitor. It is an analog of sildenafil and vardenafil. Homosildenafil was first identified as an adulterant in sex enhancement products in 2003 and was more recently detected in dietary supplements.
Desmethylsibutramine is an active metabolite of the anorectic drug sibutramine. It is a more potent monoamine reuptake inhibitor than sibutramine and has been sold as an ingredient in weight loss products sold as dietary supplements, along with related compounds such as the N-ethyl and 3,4-dichloro derivatives.
5α-Hydroxylaxogenin is a chemical compound which is a semi-synthetic derivative of laxogenin, found in the Chinese medicinal plant Smilax sieboldii. It acts as a partial agonist at androgen receptors and has been sold as a bodybuilding supplement and pre-workout product.
Chlorosipentramine is an analogue of the anorectic drug sibutramine, which has been sold as an ingredient in weight loss products sold as dietary supplements, first detected in South Korea in 2017. It is one of a number of sibutramine derivatives which have been sold in grey-market weight loss products since sibutramine itself was taken off the market due to safety concerns. Others include desmethylsibutramine, didesmethylsibutramine, homosibutramine, chlorosibutramine, and benzylsibutramine. Chlorosipentramine is illegal in South Korea along with other related compounds.
