Scientific background and prospects for the use of sildenafil 50 mg in patients with COVID-19

Currently, there are only theoretical prerequisites for the use of the drug sildenafil 50 mg for the treatment of patients with COVID-19. There are no clinical data to recommend the use of this drug in real practice for the prevention and relief of symptoms in patients with COVID-19. The use of sildenafil in the treatment of a new coronavirus infection is possible only as part of clinical trials.

Introduction

Sildenafil 50 mg (ATX code G04BE03) is a selective inhibitor of cycloguanosine monophosphate (cGMP), a specific phosphodiesterase -5 (PDE5). Since PDE5, which is responsible for the breakdown of cGMP and the accumulation of the dilating effect of nitric oxide (NO), is found not only in the cavernous body of the penis, but also in the vessels of the lungs, side effects of sildenafil, being an inhibitor of this enzyme, increases the content of cGMP in the smooth muscle cells of the pulmonary vessels and causes them relaxation. In patients with pulmonary hypertension, taking sildenafil 50 mg leads to pulmonary vasodilation, and to a lesser extent other vessels.

Sildenafil is currently used for the following approved indications:

• treatment of erectile dysfunction (ED) in men;
• pulmonary hypertension.

Bacterial or viral infections often cause acute and severe systemic inflammation, which is realized through the pathogenic component of the membrane of gram-negative bacteria, which stimulates active cells of innate immunity, monocytes, macrophages, and leads to the production of inducible nitric oxide synthase (iNOS). A number of researchers note the positive effect of inhalation of nitric oxide (NO) on the severity of interstitial changes in the lung tissue.

Sildenafil drug class.These circumstances served as theoretical prerequisites for the rationale for the appointment of sildenafil 50 mg and other PDE5 inhibitors in COVID-19. To date, among the many attempts to identify new treatments for COVID-19 or re-evaluate the value of well-known drugs, several studies have focused on the effectiveness of members of this pharmacotherapeutic group.

Used primarily in the treatment of male erectile dysfunction and pulmonary hypertension, PDE5 inhibitors in patients with COVID-19 may be able to suppress SARS-CoV-2 replication, reduce the severity of acute respiratory syndrome and prevent inflammatory thromboembolism.

Possibility and prerequisites for the use of sildenafil in COVID-19

Many researchers have repeatedly pointed out that the mechanisms of virus entry into the cell are mediated by the S-protein of the angiotensin -converting enzyme type 2 receptor, but some researchers suggest that such a mechanism may not be the only culprit for the development of severe inflammatory processes in patients with COVID-19.

Several studies published over the past decade provide evidence that certain pathways involving PDE5, especially the NO/ cGMP /PDE5 pathway, may be involved in the development of inflammatory processes in patients.

How to take, course of administration and dosage

Sildenafil 100mg price is taken orally. The recommended dose for most adult patients is 50 mg approximately 1 hour before sexual activity. Based on efficacy and tolerability, the dose may be increased to 100 mg or reduced to 25 mg.
The maximum recommended dose is 100 mg. The maximum recommended frequency of use is 1 time per day.