Phosphodiesterase type 5 (PDE5) inhibitors are a class of medications primarily used to treat erectile dysfunction (ED). They work by blocking the enzyme PDE5, which is responsible for breaking down cyclic guanosine monophosphate (cGMP) in the smooth muscle cells lining the blood vessels supplying the corpus cavernosum of the penis. By inhibiting this enzyme, PDE5 inhibitors facilitate an increase in cGMP levels, which leads to relaxation of smooth muscle and increased blood flow into the penis during sexual stimulation, thus facilitating an erection.
The most well-known oral PDE5 inhibitors include sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra). Each of these medications varies slightly in terms of its chemical structure, duration of action, onset of action, and side effects:
Sildenafil (Viagra): Typically taken about an hour before sexual activity; its effects can last for up to four hours. Common side effects include headache, facial flushing, and indigestion.
Tadalafil (Cialis): Known for its long-acting nature, tadalafil can be effective for up to 36 hours and can be taken with or withuot food. It offers more spontaneity but may also cause back pain and muscle aches.
Vardenafil (Levitra): Similar to sildenafil in terms of onset and duration; it also requires about an hour to start working and has similar side effects like headaches and facial flushing.
Avanafil (Stendra): The newest among them, avanafil has a quicker onset of action compared to others; it can start working in as little as 15 minutes after intake. Side effects are similar but potentially less intense.
When considering PDE5 inhibitors for treating ED, it’s necessary for individuals to consult with their healthcare provider to determine the most appropriate option based on their overall health status and other medications they might be taking since these drugs can interact with other treatments leading to adverse consequences. For example, they should not be used by individuals taking nitrates such as nitroglycerin due to potential risk of severe hypotension.
Additionally, while PDE5 inhibitors are effective for many men suffering from erectile dysfunction caused by physical factors such as poor blood flow to the penis or nerve damage from conditions like diabetes or prostate surgery, they might not be effective when ED is caused by psychological issues such as anxiety or depression. In such cases, counseling or therapy might also be recommended as part of treatment strategy.