The mechanism of action of Viagra
The mechanism of action of Viagra is closely related to NO (nitric oxide). Sexual stimulation leads to the release of NO in the blood vessels of male genitalia, which stimulates guanylate cyclase and increases the level of cyclic guanosine phosphate in the corpus cavernosum of the penis, leading to vasodilation and congestion, leading to penile erection. Patients with erectile dysfunction, on the other hand, experience a decrease in NO production, resulting in a decrease in cyclic guanosine monophosphate levels and inability to achieve normal penile erection.
To explain the mechanism of action of Viagra, the researcher in charge of this study used an analogy where NO is the faucet, cGMP (cyclic guanosine phosphate) is water, and PDE (phosphodiesterase) is an open drain.
For normal people, sexual stimulation can turn on the faucet and drain water quickly. Even if the drain is open, the drainage speed cannot drain the bathtub, so the bathtub can be quickly filled. For patients with erectile dysfunction, the situation is not good. The faucet is not fully open and the drain is still open, so there is no water left in the bathtub. Instead of opening the faucet wider, it is better to close the drain, so that the water is not fully stored?
The function of Viagra is to close this drain, which inhibits PDE (phosphodiesterase) and has a therapeutic effect. Moreover, Viagra does not work without sexual stimulation. This is definitely good news for patients, as they would rather not have an erection when it is not appropriate. NO only appears after sexual stimulation, and even when taking Viagra, sexual stimulation is required to evoke an erection in the penis, making the modified erection effect closer to the natural effect.
(Special reminder: Due to the similar mechanism of action of nitroglycerin and “Viagra” in the human body, they must not be taken simultaneously to avoid serious blood pressure drop or even sudden death of the user.)
Nowadays, Viagra has covered nearly 200 countries and regions, and has brought generous returns to Pfizer with an average annual revenue of $1 billion and a strong brand effect. With a sales contribution of over ten billion US dollars, Viagra has become one of the most well-known drugs in Pfizer and even in the world’s pharmaceutical history.
Some herbals have the fuction of the PDE5 inhibitor, this is one of our research and development directions.
