Viagra is a PDE5 inhibitor. PDE5 is an enzyme that promotes the degradation of cGMP in the blood, cGMP regulates blood volume in the penis, so reducing cGMP makes it difficult for men to get an erection. Viagra acts primarily on the circulatory and reproductive systems.

Viagra is a powerful drug that increases blood flow to the penis and maintains an erection. Viagra is highly effective, but it can cause some side effects. What are the side effects of Viagra?

Hot flashes are a fairly common symptom in women, especially in premenopausal women. Hot flashes can make women feel frustrated, uncomfortable and cause frequent sleep loss.

Hot flashes are a fairly common symptom in women, especially in premenopausal women. Hot flashes can make women uncomfortable, tired and often lose sleep.

Alzheimer's disease is a progressive memory loss that can greatly affect the elderly. Currently, people still do not clearly understand the disease, including the cause or effective treatment.