What are PDE5 inhibitors?

The most common cause of sexual dysfunction in men is mostly thought to be ED, and it becomes more frequent with age. It is reported that in the United States, between 30 million and 50 million men struggle with Erectile Dysfunction.

For people with ED, PDE5 inhibitors are always the first therapeutic choice caused by inadequate blood flow to the penis. We will break down the most popular forms of PDE5 inhibitors on the market in this article. We look at how they operate, what they are used for, and how much they cost, as well.

A type 5 inhibitor of phosphodiesterase (PDE5 inhibitor) is a vasodilating agent that acts by blocking the degrading activity of type 5 phosphodiesterase (PDE5) specific to cGMP on cyclic GMP in the smooth muscle cells lining the blood vessels supplying different tissues. These medications dilate the penis corpora cavernosa, promote erection with sexual arousal, and are used to treat erectile dysfunction (ED). The first effective oral drug available for ED was Sildenafil. Tadalafil and Sildenafil are FDA approved for the treatment of pulmonary hypertension since PDE5 is also found in the smooth muscle of the walls of the arterioles inside the lungs. As of 2019, the greater cardiovascular effects of inhibitors of PDE5 have been noted.

Medical uses of PDE5 inhibitors

Inhibitors of phosphodiesterase-5 (PDE5) are clinically recommended for the treatment of erectile dysfunction, such as sildenafil (Viagra, Fildena 100), tadalafil (Cialis), and vardenafil (Levitra). For the treatment of some subtypes of pulmonary hypertension, sildenafil and tadalafil are both recommended, while tadalafil is also approved for the treatment of benign prostatic hyperplasia.

In extreme cases of the Raynaud syndrome where it is associated with systemic sclerosis, PDE5 inhibitors have been used as a second-line treatment according to the recommendations of the European Society for Vascular Medicine.

Contraindications of PDE5 inhibitors

PDE5 inhibitors are contraindicated if alpha-blockers, soluble guanylate cyclase stimulators, or nitrate medications such as isosorbide mononitrate or isosorbide dinitrate are taken within 24 hours (or 48 hours with Tadalafil). Concurrent use of these medications can lead to decreased blood pressure that is life-threatening. In patients with prior nonarteritic anterior ischaemic optic neuropathy and inherited eye disorders, PDE5 inhibitors are also contraindicated.

Given initial fears of adverse coronary outcomes in patients prescribed PDE5 inhibitors, numerous long-term trials have confirmed the efficacy of the medications in both stable patients and patients with cardiovascular risk factors.

Side Effects of PDE5 inhibitors

Headaches, flushing, runny nose, stomach pain, back pain, and indigestion are typical side effects. For patients with liver and/or kidney illness, smaller doses are used. Dizziness or a sudden decrease in blood pressure can be caused by PDE5 inhibitors. Until beginning to use PDE5 inhibitors, men with heart disease need a doctor’s examination and will need lower doses of PDE5. Some men endure erections that are persistent or painful. There may be sensory complications (for example, blurred vision, heightened light intensity, bluish haze, or transient difficulties differentiating between blue and green).

How PDE5 inhibitors work?

Part of the vasodilatation physiological mechanism involves the release by vascular endothelial cells of nitric oxide, which then diffuses to neighbouring vascular smooth muscle cells. There, soluble guanylate cyclase is activated by NO, which transforms guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP), the main device effector. For eg, in the penis, during sexual stimulation, NO escape from endothelial cells and penile nerves at high levels contributes to the relaxation of the smooth vasculature of the cavernous corpus, causing vasocongestion and prolonged erection.

By inhibiting its degradation by the enzyme PDE5, which is present in the body, PDE5 inhibitors prolong cGMP’s action. In the penis, cGMP’s effects are potentiated by PDE5 inhibitors to prolong erections and enhance sexual pleasure. However, without sexual arousal, PDE5 inhibitors do not induce erections.

Please contact your doctor before taking any kind of medicine.