As men reach their middle age, their desire for sex can sometimes be accompanied by frustration due to their inability to maintain or at times, even obtain an erection. And while this may not a big deal in men of an old age; it can be a very displeasing issue for younger men. It’s for this reason that these men turn to Viagra for help.
As men get older, their desire to perform a sexual act can be frustrated by their unenthusiastic member. They are suffering from what is technically called erectile dysfunction (ED). Viagra is the trade name for sildenafil citrate. It was discovered at the Pfizer laboratories in Sandwich, Kent, England in the late 1985. In a way, the discovery could be said to be accidental, because the initial purpose of team that discovered viagra billigt was to find a treatment for angina.
How Viagra works
To produce an erection, a man has to be sexually stimulated—by thought word, or deed—and this releases nitric oxide (NO) from nerve endings in the spongy cells of the penis. This simple molecule then kicks into action an enzyme, guanylate cyclase that produces cCMR which then relaxes the muscles supplying the penis with blood, which causes more blood to flow to the penis. As a result, the penis enlarges, and eventually becomes so engorged with blood that it stands erect.
Meanwhile, another enzyme called phosphodiesterase is present to remove cCMR albeit at a rate that cannot cope with the rush of NO and cCMR. As a man gets older the bodys production of these chemicals becomes insufficient to counteract the neutralizing effect of the phosphodiesterase enzymes, and the result is impotence in the form of partial erections or unsustainable erections. Viagra corrects these dysfunctions by blocking the neutralizing phosphodiesterase enzyme.
But why should Viagra affect only the penis, when cCMP production and removal are used in many other parts of the body? The answer lies with the phosphodiesterase, of which there are several varieties, the one in the penis being phosphodiesterase-5.
Viagra deactivates this while leaving other phosphodiesterases, such as the one in heart muscle (phosphodiesterase-3), unaffected. Viagra is just the right molecular size to fit the active centre ofphosphodiesterase-5and block it. Until the enzyme can free itself of its unwanted burden, it is inactive against its real target molecule, cCMR and so the level of this builds up in the penis and continues to be high while the man remains sexually aroused.
Viagra’s side effects
Viagra can be risky, especially if taken in conjunction with poppers, the street name for volatile nitrites. The combination of these two drugs can cause such a dilation of the arteries that cardiovascular collapse is a real threat.
If an angina patient is taking nitrates or alpha-blockers for chest pain, it could be very dangerous to combine these substances with Viagra at the same time. They work together to cause uncontrolled dilation in your vessels causing hypotension, shock and inadequate blood perfusion. The side effects of Viagra, such as headaches and feeling dizzy, are due to the dilation of blood vessels in the brain. Another side effect of Viagra is temporarily to give some men blue-tinted vision. The latter effect is because the cone cells responsible for color vision also rely on the phosphodiesterase-5 blocked by Viagra. Flushing in the face can also take place as a result of the dilation of the blood vessels in the cialis bästa pris face. Stomach upset is a common side effect produced by Viagra, so patients with stomach ulcers or GERD may be subject to higher levels of discomfort than other patients. The Food and Drug Administration (FDA) had to put a black labeled warning box on the Viagra medication due to reports saying that a very rare condition of sudden hearing and visual loss may take place in the elderly.
People with penis abnormalities and medical conditions that have prolonged erections as a symptom such as sickle-cell anemia, multiple myeloma, leukemia should also be careful while taking medications like Viagra. Patients with Hereditary degenerative retinal disorders and uncontrolled hypertension should be contraindicated to take Viagra. Patients with Impaired Liver functions and Impaired Kidney function should be advised to go to the doctors to adjust the dosage according to the level of the disease. It is notable that in spite of the widely advertised side effects of Viagra, only 2 % of people taking Viagra quit it because its side effects so 98 % of people don’t experience side effects at all.