VIAGRA (sildenafil citrate) is a c GMP-specific phosphodiesterase type 5 (PDE5) inhibitor, used for the treatment of male erectile dysfunction. The physiological mechanism responsible for erection of the penis involves the release of nitric oxide (NO) in the in response to sexual stimulation. Nitric oxide then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (c GMP), producing smooth muscle relaxation in the have shown that sildenafil has between 10 and 10,000-fold greater selectivity for PDE5 than for other phosphodiesterase isoforms namely PDEs 1, 2, 3, 4, and 6 and greater than 700-fold effect on PDE7-PDE11. In particular, sildenafil has greater than 4,000-fold selectivity for PDE5 over PDE3, the c AMP-specific phosphodiesterase isoform involved in the control of cardiac contractility. Sildenafil is about 10-fold as potent for PDE5 compared to PDE6, an isoenzyme found in the retina; this lower selectivity is thought to be the basis for colour vision abnormalities observed with higher doses or plasma levels of sildenafil (see WARNINGS AND PRECAUTIONS, DETAILED PHARMACOLOGY). PDE5 is also found in lower concentrations in platelets, vascular and visceral smooth muscles, and skeletal muscle. The sildenafil-induced inhibition of PDE5 in these tissues appears to be the basis for the enhanced platelet antiaggregatory activity of nitric oxide observed (see WARNINGS AND PRECAUTIONS). diflucan oral tablet The primary indication of sildenafil is treatment of erectile dysfunction (inability to sustain a satisfactory erection to complete intercourse). Its use is now one of the standard treatments for erectile dysfunction, including for men with diabetes mellitus. Rare but serious adverse effects found through postmarketing surveillance include prolonged erections, severe low blood pressure, myocardial infarction (heart attack), ventricular arrhythmias, stroke, increased intraocular pressure, and sudden hearing loss. Care should be exercised by people who are also taking protease inhibitors for the treatment of HIV infection. Protease inhibitors inhibit the metabolism of sildenafil, effectively multiplying the plasma levels of sildenafil, increasing the incidence and severity of side effects. Those using protease inhibitors are recommended to limit their use of sildenafil to no more than one 25 mg dose every 48 hours. blocker (typically prescribed for hypertension or for urologic conditions, such as benign prostatic hypertrophy) at the same time may lead to low blood pressure, but this effect does not occur if they are taken at least 4 hours apart. Cialis dallas Feb. 2014 - 5 minThis video is part of a global eLearning initiative for Pfizer. The goal of this initiative is to educate. can u buy cialis in canada Learn about Viagra Sildenafil Citrate may treat, uses, dosage, side effects, drug interactions, warnings, patient labeling, reviews, and. Mechanism Of Action. Expert Opin Drug Metab Toxicol. 2005 Aug;12283-93. Sildenafil efficacy, safety, tolerability and mechanism of action in treating erectile dysfunction. Francis. This was the first of a group of drugs called phosphodieterase inhibitors or PD5 inhibitors for short. They work by allowing an increase of blood into the penis and maintaining the erection for longer. It’s a bit like filling a bath – if you turn the taps on full the bath will fill, even though the plug is out. Other drugs like Cialis and Levitra are variations on the same theme but with their own characteristics. low sex drive, lack of morning erections, less intensity during ejaculation, less hard erections, irritability, etc.. I had my doctor run blood tests and everything came back normal. Doctor says this is normal and will not consider hormone treatments. The only medication I take is a statin, which has lowered my cholestorol to normal levels. Hi I m a 28 year old and suffer some degree of ED in recent. Sildenafil is a vasoactive agent used to treat erectile dysfunction and reduce symptoms in patients with pulmonary arterial hypertension (PAH). Sildenafil elevates levels of the second messenger, c GMP, by inhibiting its breakdown via phosphodiesterase type 5 (PDE5). PDE5 is found in particularly high concentrations in the corpus cavernosum, erectile tissue of the penis. It is also found in the retina and vascular endothelium. Increased c GMP results in vasodilation which facilitates generation and maintenance of an erection. The vasodilatory effects of sildenafil also help reduce symptoms of PAH. Sildenafil mechanism of action Sildenafil, Viagra Generic Facts, Side Effects, Dosage, Viagra Sildenafil Citrate Side Effects, Interactions, Warning, Dosage. Cheap viagra commercial Effects and mechanism of action of sildenafil. Arulkumaran S. Relaxant action of sildenafil citrate Viagra on human myometrium of pregnancy. Effects and mechanisms of action of sildenafil citrate in. Sildenafil efficacy, safety, tolerability and mechanism of action. - NCBI Effects and mechanisms of action of sildenafil citrate in human. Thus, sildenafil is a phosphodiesterase-5 inhibitor. Since the levels of cGMP rise, smooth muscles in the corpus cavernosum and the vasculature of the lungs relax. viagra toronto kijiji Sildenafil citrate is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7. VIAGRA is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and 100 mg of sildenafil for oral administration. With the introduction of sildenafil. The drug acts. the question of individual choice. Key words erectile dysfunction sildenafil nitric oxide. Mechanism of action.