Sildenafil danger, risk, toxicity, a selective phosphodiesterase-type-5 (PDE-5) inhibitor
Sildenafil produces blood vessel dilation that improves erectile dysfunction and pulmonary hypertension.
November 29 2017

Sildenafil citrate, known as Viagra, is a vasoactive agent available worldwide since 1998 for the treatment of male erectile dysfunction. It is a selective phosphodiesterase type 5-enzyme inhibitor able to potentiate the downstream effects of nitric oxide on smooth muscle relaxation and vasodilation through its effects on the cyclic guanosine monophosphate (c-GMP) pathway in the erectile tissue of the penis.

Safety, toxicity, danger, risk, how safe is it?
Hemoptysis and respiratory failure following sildenafil use for pulmonary hypertension. East Tennessee State University, USA. Tenn Med. 2013.
Sildenafil, usually a well-tolerated phosphodiesterase inhibiting drug traditionally used for erectile dysfunction (ED), was recently approved for pulmonary arterial hypertension. In the literature, there are few cases of hemoptysis following sildenafil use for ED; however, to our knowledge, we are reporting the first case of hemoptysis following sildenafil use for pulmonary hypertension. We are documenting a case of a 90-year-old male patient who was admitted to the intensive care unit with hemoptysis and respiratory failure two weeks after he was started on sildenafil.

J Med Assoc Thai. 2013 .The efficacy and safety of on-demand Elonza; a generic product of sildenafil in Thai men with erectile dysfunction. The most frequent treatment-emergent adverse events were flushing (13%), nasal congestion (9%), abnormal vision (5%), headache (4.4%), dizziness (3%), and dyspepsia (0.5%). Elonza was an effective and well-tolerated treatment for ED in Thai men.

Turk Kardiyol Dern Ars. 2012. Does sildenafil contribute to acute coronary thrombosis? Department of Cardiology, Ada Medical Hospital, Sakarya, Turkey. Sildenafil-associated myocardial infarction (MI) is rarely seen in patients without previous history of coronary artery disease. A 43-year-old man presented with sudden onset of chest pain. It was determined that his chest pain started after sildenafil intake. Findings consistent with acute anterior MI were observed on electrocardiography. Coronary angiography showed total occlusion of left anterior descending artery with thrombosis. Coronary angioplasty and stenting was successfully performed.

Liver damage or hepatoxicity
Eur Rev Med Pharmacol Sci. 2017. Sildenafil-associated hepatoxicity: a review of the literature. When sildenafil is orally administered, it is rapidly absorbed with a maximum plasma concentration achieved within 1 h and has a terminal half-life of between 3 to 6 h. The drug is extensively and rapidly metabolized by the liver, primarily by the CYP3A4 enzyme. Although the drug is well tolerated, specific adverse events have been observed, like flushing, headaches, dyspepsia, and visual disturbances. Liver toxicity related to sildenafil consumption has been considered a very rare event. However, in the last decade, some cases of sildenafil-associated hepatotoxicity have been reported.

Muscle damage can occur with muscle pain and achiness
Rhabdomyolysis Induced by Rosuvastatin and Sildenafil; Pennisi G, Vacante M, Russo C, Malaguarnera M; Southern Medical Journal, Sep 2010. A 66-year-old man with diabetes and hypertension using statin was admitted to the hospital with progressive myalgia. He had been on rosuvastatin for five months. After beginning the use of phosphodiesterase-5 inhibitors, he presented with severe muscle pain and maintained penile erection. Several days after interruption of therapy, muscle pain and penile erection disappeared. This case demonstrates the interaction of sildenafil with rosuvastatin might result in myopathy.

Vision and eye health, can cause vision loss
Does Therapeutic Dose of Sildenafil Citrate Treatment Lead to Central Serous Chorioretinopathy in Patients With Erectile Dysfunction? Ministry of Health, Ankara Ataturk Research and Training Hospital, Department of Ophthalmology, Ankara, Turkey. Am J Mens Health. 2013.
The possible effects of sildenafil citrate administration at therapeutic dosage on visual acuity, color vision, intraocular pressure, macular thickness, macular volume, and central serous chorioretinopathy in patients with erectile dysfunction were evaluated. The study consisted of 43 male patients diagnosed as having erectile dysfunction according to the first five question version of International Index of Erectile Function (IIEF-5). All patients were given sildenafil citrate 50 mg po 2 to 3 times/week for a month. The patients were evaluated at the first week and at the end of the treatment. The macular thickness and volume assessments with optic coherence tomography did not differ significantly in foveal, parafoveal areas, parafoveal superior hemisphere, parafoveal inferior hemisphere, parafoveal temporal, superior, nasal, and inferior quadrants. Central serous chorioretinopathy was not found in any of the patients.

Combining with testosterone hormone
The addition of testosterone to sildenafil in men with ED and low serum testosterone levels was not associated with improvement in either well-being or mood. Andrology. 2013. The effect of testosterone on mood and well-being in men with erectile dysfunction in a randomized, placebo-controlled trial. Section of Endocrinology Diabetes and Nutrition, Boston University School of Medicine and Boston Medical Center, Boston, MA, USA.

Natural over the counter impotence pills that are laced with prescription or unapproved medications
J Pharm Biomed Anal. 2012. Analysis of herbal dietary supplements for sexual performance enhancement: first characterization of propoxyphenyl-thiohydroxyhomosildenafil and identification of sildenafil, thiosildenafil, phentolamine and tetrahydropalmatine as adulterants. Groupe de RMN Biomédicale, Laboratoire SPCMIB, Université Paul Sabatie, Toulouse Cedex, France. Nine herbal dietary supplements intended to be beverages for enhancing sexual performance were analyzed before their possible launch on the market. Four of them contained a sildenafil analog reported for the first time as an adulterant. After isolation and characterization using NMR, MS, IR and UV, this analog was named propoxyphenyl-thiohydroxyhomosildenafil as the ethoxy chain on the phenyl ring of the already known analog thiohydroxyhomosildenafil was replaced by a propoxy moiety. One formulation was tainted with thiosildenafil, another unapproved PDE-5 inhibitor. Sildenafil along with the natural alkaloid tetrahydropalmatine that has no documented effect for enhancing erectile dysfunction were identified in two formulations. Another formulation was adulterated with phentolamine, a drug that is not approved for boosting male sexual performance when taken orally. The last formulation containing osthole, a bioactive natural coumarine improving sexual dysfunction, is most probably truly natural.

Arch Ital Urol Androl. 2013. Comparison of tamsulosin vs tamsulosin/sildenafil effectiveness in the treatment of erectile dysfunction in patients affected by type III chronic prostatitis. Tamsulosin monotherapy, as well as a combination therapy (tamsulosin plus sildenafil) has an improving effect on symptoms and on ED in patients with type III prostatitis.

Use in those who have depression
Sildenafil may be a beneficial treatment for antidepressant-induced sexual dysfunction. Ann Clin Psychiatry. 2013 Feb. The effect of sildenafil on quality of life.

Use by women
Akush Ginekol (Sofiia). 2013. The effect of vaginal sildenafil citrate on uterine blood flow and endometrium in the infertile women. Combination of Sildenafil citrate and Serophene is an effective agent as a first-line of treatment for ovulation induction.