Does sildenafil improve ventilatory function in asthmatic subjects?

Sildenafil: From angina to SARS-CoV-2

Sildenafil was first examined as an alternative to nitrates for the management of angina pectoris and hypertension and eventually developed into an oral therapeutic agent used for the treatment of erectile dysfunction. There are appropriate indicators that PDE5 inhibitors may also modify the detrimental consequences of the immune system over-stimulation, supplying a new chance for their use in SARS-CoV2 patients. The use of sildenafil for the management of SARS-CoV2 has been suggested based on its several mechanisms of action and therapeutic effects and on the clinical features of SARS-CoV2 which similar to those of other pathologies treated with the PDE5 inhibitors. Here we review fundamental highlights in the enhancement of sildenafil for numerous scientific disorders and consider practicable new uses for this versatile drug.

Experimental and investigational phosphodiesterase inhibitors in development for asthma

INTRODUCTION

Severe, inadequately-controlled asthma remains a clinical challenge. For this reason, clinical trials and preclinical experimental studies on novel agents as an add-on therapies continue emerge. Phosphodiesterases (PDEs) are enzymes that regulate the function of immune cells by hydrolyzing cyclic guanosine monophosphate/cGMP and cyclic adenosine monophosphate/cAMP. PDEs are divided into subfamilies [PDE3, PDE4, PDE5 and PDE7] which are mainly found in the respiratory tract. Inhibitors of PDEs have already been approved for COPD and pulmonary hypertension.

AREAS COVERED

The role of PDE inhibitors in asthma treatment and the possible mechanism of action via their anti-inflammatory and/or bronchodilating effect are discussed.

EXPERT OPINION

Novel PDE inhibitors exhibiting fewer adverse events may have a role as add-on therapies in asthma treatment in the future. More clinical trials are necessary to prove their efficacy and evaluate their safety profile before approval by regulatory bodies is granted.

Investigating the effect of sildenafil on improving lung function and quality of life in the patients with severe asthma

Introduction:

Phosphodiesterase inhibitors (PDEs) increase intracellular cyclic adenosine monophosphate, which results in a wide range of anti-inflammatory effects and pathologically leads to improve asthma disease. Because no human study has surveyed the effect of PDEs on pulmonary function, except some case reports and animal researches, we decided to perform a pilot study for evaluating the effect of sildenafil (PDE5) on pulmonary function in patients with severe asthma.

Methods:

This randomized controlled trials study was conducted on 20 patients with severe asthma in 2019 in Iran. For case group, was prescribed sildenafil (50 mg) daily and the control group received the placebo. In the beginning of the study and one month later, volume parameters, 6-minute walk distance (6MWD), and the quality-of-life questionnaire were measured and compared in the two groups.

Results:

Twenty patients were entered into this study. 8 patients (40%) were male and 12 (60%) were female. The results showed that mean forced vital capacity 1 in the sildenafil group turned from 1259 ± 170 to 1603 ± 527, while in the placebo group it changed from 1135 ± 125 to 1365 ± 251 (P-value = 0.215). There is no statistically significant difference between two groups. In addition, in comparison with placebo, sildenafil did not show any significant improvement in the volume parameters, the quality-of-life questionnaire scale, and 6MWD at the end of the study.

Conclusion:

According to present result can be concluded that sildenafil does not improve the severity of asthma and the quality of life in patients with severe asthma.