The prevalence of ED increases with age and can be influenced by a variety of factors including psychological issues, health conditions like diabetes and heart disease, and certain medications. Erectile dysfunction is a condition where a man is unable how to get doxycycline without prescription achieve or maintain an erection adequate for satisfactory sexual performance. The most common adverse effects include headaches, flushing, dyspepsia, nasal congestion, and impaired vision. Therefore, Viagra must be used under appropriate medical supervision.

Despite its success, Viagra is not devoid of side effects. More serious but rare side effects include priapism, a condition where an erection lasts longer than four hours and can cause permanent damage to the penis. The recommended starting dose is 50 mg, but this can be adjusted based on efficacy and tolerability. Its effects can last for up to four hours, providing ample time for satisfactory sexual intercourse.

Viagra is typically taken orally, in the form of a pill, approximately 30 minutes to an hour before sexual activity. It's crucial for users to follow medical advice strictly and avoid exceeding the prescribed dosage to prevent adverse effects. More serious but rare side effects can include priapism (a painful erection lasting longer than four hours), sudden hearing loss, or vision loss. The drug is generally safe for most men, but it is not devoid of side effects.

Common adverse reactions include headaches, facial flushing, indigestion, nasal congestion, and, less commonly, changes in vision such as increased sensitivity to light or blurred vision. Individuals with cardiovascular conditions, particularly those taking nitrate drugs for chest pain, are advised against using Viagra due to the risk of severe blood pressure drops. Furthermore, ongoing research is investigating the potential of Viagra in other areas, such as its effects on heart function, diabetes-related complications, and even certain types of cancer, demonstrating the broad therapeutic potential of this medication beyond its initial indication.

By blocking PDE5, Viagra enhances the effects of NO by prolonging the duration and effect of cGMP, thus improving the ability to achieve and maintain an erection in the presence of sexual stimulation. Viagra works by inhibiting an enzyme known as phosphodiesterase type 5 (PDE5), which is responsible for the breakdown of cGMP in the corpus cavernosum. Since its accidental discovery and subsequent release by Pfizer in 1998, Viagra has become one of the most well-known and frequently prescribed drugs in the world for enhancing sexual function.

Viagra, chemically known as sildenafil citrate, is a medication primarily used to treat erectile dysfunction (ED) in men. The mechanism of action of Viagra involves the enhancement of nitric oxide (NO) effects in the corpus cavernosum of the penis. NO is a natural chemical that relaxes muscles in the penis, increases blood flow, and allows for an erection in response to sexual stimulation. Elevated levels of cGMP lead to smooth muscle relaxation and increased blood flow to the penis, facilitating the erection process.

Viagra works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which results in an increase in the levels of cyclic guanosine monophosphate (cGMP).