Phosphodiesterase 5 (PDE5) inhibitors are a class of drugs that can affect the blood flow and the way cells communicate in the body. PDE5 inhibitors can also appear in certain foods and supplements.
People can take his PDE5 inhibitors to manage conditions such as erectile dysfunction (ED) and pulmonary hypertension.
This article explains how PDE5 inhibitors work and the potential risks and side effects of taking them. It also provides a list of drugs and substances that contain them.
What are PDE5 inhibitors?
PDE5 is an enzyme found in the walls of blood vessels. It affects blood flow, and the way cells send signals in the body.
PDE5 inhibitors block the PDE5 enzyme, preventing it from working. This inhibition relaxes blood vessels and increases blood flow.
People can take PDE5 inhibitors to treat erectile dysfunction or pulmonary hypertension.
In people with erectile dysfunction, PDE5 inhibitors increase blood flow to the penis, thereby improving erectile function.
In people with pulmonary hypertension, PDE5 inhibitors may:
- Controls blood flow to the arteries of the lungs
- Increase blood flow to the lungs
- Lower blood pressure
- Research also suggests that PDE5 inhibitors may help treat heart disease, diabetes, and cancer.
- Current research is investigating whether PDE5 inhibitors are also effective in treating cognitive disorders such as dementia.
Find out more about the best erectile dysfunction drugs here.
History of oral PDE5 inhibitors
In the mid-1980s, the association of NO with the PDE family sparked pharmaceutical innovation. The many physiological effects of NO have had a dramatic impact on many diseases. The PDE enzyme is ubiquitous in the body, with 11 different recognition isoenzymes that are expressed at different concentrations in different tissues. PDE5 enzymes are common, but more common in penile tissue. Non-selective PDE inhibitors (such as theophylline) were used before the discovery of the association between NO and PDE, but selective PDE inhibitors had not yet been developed. Since then, many selective PDE inhibitors have been approved for the treatment of disorders ranging from erectile dysfunction to pulmonary hypertension.
Sildenafil (Viagra), first studied in clinical trials for coronary heart disease in 1991, happened to have a favorable effect on penile erection. In 1998, Viagra was approved by the FDA as the first oral treatment for erectile dysfunction. As the market potential of oral PDE5 inhibitors became recognized, pharmaceutical companies began developing and improving new products. Different potency, duration of action, and onset of action have created alternative therapies for PDE5 inhibitors, including Cialis (2003), Levitra (2003), and Stendra (2012) for the treatment of erectile dysfunction. Approval has been reached. In 2008, Cialis received his first marketing approval for once-daily dosing. Viagra’s patent was extended until 2020, but Pfizer struck a deal with a generic manufacturer to market sildenafil in 2017, making the drug the first generic PDE5 inhibitor. Generic versions of Cialis and Levitra. will be available in the second half of 2018.
Mechanism of Action of PDE5 Inhibition in Erectile Dysfunction
The spinal reflex and the L-arginine-nitric oxide-guanylate cyclase-cyclic guanosine monophosphate (cGMP) pathway mediate smooth muscle relaxation leading to penile erection. Nerve and endothelial cells release nitric oxide directly into the penis where it stimulates guanylyl cyclase to produce cGMP and lower intracellular calcium levels. This causes relaxation of arterial and trabecular smooth muscle, leading to dilation of arteries, constriction of veins and erection. Phosphodiesterase 5 (PDE5) is the major phosphodiesterase in the corpus cavernosum. The catalytic site of PDE5 normally degrades cGMP, and PDE5 inhibitors such as sildenafil potentiate the endogenous increase in cGMP by inhibiting degradation at the catalytic site. Phosphorylation of PDE5 increases its enzymatic activity and affinity of the allosteric site (non-catalytic/GAF domain) for cGMP. Binding of cGMP to the allosteric site further stimulates enzymatic activity. Thus, phosphorylation of PDE5 and binding of cGMP to non-catalytic sites induces negative feedback regulation of the cGMP pathway.
Prescription PDE5 inhibitor
Various PDE5 inhibitors are available, and people usually take them in pill form.
The following prescription PDE5 inhibitors are available in the United States:
Avanafil, brand name Stendra, is a relatively new treatment for erectile dysfunction. Older studies show that this drug works faster than other erectile dysfunction treatments, taking effect about 15 minutes after ingestion and lasting up to 6 hours, which is not long, Like Avana 100.
Additionally, a 2016 study showed that Avanafil has fewer side effects and a shorter onset time than other erectile dysfunction drugs, making people more willing to have sex.
Vardenafil, brand name Levitra Vilitra 60, reaches its maximum effect about 60 minutes after ingestion. Lasts up to 12 hours in the body.
Tadalafil (Cialis, Adcirca)
Tadalafil, known by the brand names Cialis and Vidalista black 80, is the slowest-acting erectile dysfunction drug, reaching its peak effect about 120 minutes after ingestion. However, it persists in the body for up to 36 hours.
Learn more about tadalafil here.
How do PDE5 inhibitors work?
PDE5 inhibitors have a vasodilating effect on the penis. This means that it helps relax blood vessels and increase blood flow.
What foods contain PDE5 inhibitors?
PDE5 inhibitors are naturally present in several herbs. These herbs are often sold in supplement form and are marketed to treat erectile dysfunction or boost male vitality.
Reliable sources with the FDA warn against dietary supplements for the treatment of erectile dysfunction because many of these products contain undisclosed ingredients that may be harmful. Its safety and effectiveness have also been poorly studied.
- Epimedium (Horny Goat Weed)
- Kaempferia parviflora (Black ginger)
- Malculra pomifera (Osage Orange)