Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Revatio) is used to improve the ability to exercise in adults with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the lungs, causing shortness of breath, dizziness, and tiredness). Children should not usually take sildenafil, but in some cases, a doctor may decide that sildenafil (Revatio) is the best medication to treat a child's condition. Sildenafil is in a class of medications called phosphodiesterase (PDE) inhibitors. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily. If you are taking sildenafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire. Sildenafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV). metformin what is it for However, patient may take drug 30 minutes to 4 hours before sexual activity. as a single dose, p.r.n., 1 hour before sexual activity. Based on effectiveness and tolerance by patient, may increase dose to maximum single dose of 100 mg or decrease dose to 25 mg. A maximum recommended dosing frequency is once daily. Erectile action: Sildenafil has no direct relaxant effect on isolated human corpus cavernosum, but enhances the effect of nitric oxide (NO) by inhibiting phosphodiesterase type 5 (PDE5), which is responsible for degradation of cyclic guanosine monophosphate (c GMP) in the corpus cavernosum. When sexual stimulation causes local release of NO, inhibition of PDE5 by sildenafil causes increased levels of c GMP in the corpus cavernosum, resulting in smooth muscle relaxation and inflow of blood to the corpus cavernosum. Absorption: Rapidly absorbed after oral administration. A high-fat meal delays the rate of absorption by about 1 hour and reduces peak levels by one-third. Metformin pancreas Sildenafil is used to treat men who have erectile dysfunction also called sexual. Without physical action to the penis, such as that occurring during sexual. valtrex dose for herpes simplex In patients receiving sildenafil with ritonavir, the maximum dosing frequency is. can be particularly sensitive to the actions of sildenafil and other vasodilators. The Biological Action of Sildenafil CitrateViagra™. of sildenafil citrate as an antianginal drugas coronary tissues use principally the pde-3 type receptors,see. Links to other sites are provided as a convenience to the viewer. Pfizer accepts no responsibility for the content of linked sites. This website is neither owned nor controlled by Pfizer. Pfizer does not endorse and is not responsible for the content or services of this site. Continue You are now leaving to enter a website neither owned nor operated by Pfizer. Links to all outside sites are provided as a resource to our visitors and do not imply an endorsement or recommendation of a particular physician by Pfizer, nor an endorsement of any Pfizer product by a telehealth provider or any physician. Pfizer accepts no responsibility or liability for the content or services of other websites. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where this enzyme works. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. When a man is sexually stimulated, his body's normal response is to increase blood flow to his penis to produce an erection. By controlling the enzyme, sildenafil helps to maintain an erection after the penis is stroked. Sildenafil action Revatio Sildenafil Citrate Side Effects, Interactions., Viagra sildenafil citrate dose, indications, adverse effects. Propecia hair loss side effects See risks and benefits of VIAGRA® sildenafil citrate. Find causes of erectile dysfunction ED, or impotence. Learn how VIAGRA® can help treat ED. What is ED? VIAGRA® sildenafil citrate Safety Info Sildenafil Citrate Sildenafil - Wikipedia What is sildenafil, and how does it work mechanism of action? Viagra sildenafil is an oral drug that is used for treating impotence or erectile disfunction, ED, the inability to attain or maintain a penile erection. low cost levitra Nov 26, 2018. Man on the tube checking how long Viagra lasts on his smartphone. Duration of action of sildenafil citrate in men with erectile dysfunction. Sildenafil is a common medication used to stimulate erections in men with erectile dysfunction ED and treat certain heart conditions. Its most commonly known form is Viagra. Many factors can.