YouYou may be surprised to learn that the drug sildenafil — better known by its brand name Viagra — has medical purposes other than treating male erectile dysfunction. It can also be used to treat lung diseases that often have poor prognosis.
Sildenafil works by inhibiting an enzyme called phosphodiesterase. through a complex pathway involving other moleculesSildenafil eventually helps to relax smooth muscles and dilate blood vessels. The latter effect is known as vasodilation. Vasodilation results in more blood flow to organs – whether that organ is the penis or the lungs.
lung disease
The vasodilation caused by sildenafil may be beneficial in lung diseases such as pulmonary arterial hypertension (PAH) or idiopathic pulmonary fibrosis (IPF). People living with PAH and IPF experience progressive shortness of breath and a chronic cough. In addition to the lungs, PAH and IPF can affect many other organ systems.
PAH is a disease that causes breathing difficulties and heart strain due to increased pressure in the arteries of the lungs, which were designed for very low pressure. Thank God, It is a rare disease, affecting one or two persons per 1,000,000 persons per year.,
IPF is a more common lung disease in which Between two and 29 people per 100,000 develop the condition per year., It is caused by repeated and chronic thickening, stiffness and scarring (fibrosis) of the lungs.
Both diseases often do not have a clear etiology, which means that doctors and researchers do not fully understand why these diseases begin and progress. Both diseases are incurable, and often get worse over time despite our best treatment options. There are currently few effective treatments, and there is always an interest in finding more.
PAH. evidence of sildenafil in
The use of sildenafil in PAH is already well established, effective and approved in Canada. There are several high quality randomized controlled trials that have demonstrated its efficacy. Improvement in exercise capacity and symptom burden, Sildenafil is commonly branded as Revatio in PAH (instead of Viagra for erectile dysfunction), although there is little difference between Viagra and Revatio, except that patients usually take Revatio. three times per day in small doses,
our recent publication Synthesized evidence from multiple PAH treatments, We looked at combining sildenafil or another drug in the same class — such as tadalafil (brand name Cialis) or vardenafil (brand name Levitra) — with a commonly used PAH drug.
The results showed that the number of clinical worsening events, such as disease progression or hospitalization, was reduced by 12.7 percent compared to placebo. Markers of exercise capacity, as measured by the six-minute walk test, also improved by about 50 meters.
Evidence of Sildenafil in IPF
The use of sildenafil in IPF is less certain, as there have been few randomized controlled trials, which are considered the gold standard of evidence. Only four trials have examined its use in IPF. A meta-analysis of this small number approached statistical significance, which suggests that the benefit would become apparent if more trials were completed.,
most recently European Respiratory Society / American Thoracic Society Guidelines To address the question of recommended against the use of sildenafil in IPF due to lack of data.
However, recently a drug (treprostinil) that works similarly to sildenafil has shown promise in patients with combined interstitial lung disease (an umbrella term of lung diseases that includes IPF) and pulmonary hypertension. Greatest effect seen in patients with diagnosed interstitial lung disease,
This further demonstrates the potential promise of drugs such as sildenafil or similar vasodilation mechanisms in the management of IPF.
why it matters
For conditions such as PAH or IPF that are incurable, there is merit in reusing drugs such as sildenafil. For one thing, developing new drugs is very expensive. For another, there are more concerns about safety with newer drugs; Since Viagra is so widely used, the side-effect profile is well known in the medical community.
For example, sildenafil is known to cause low blood pressure and should be avoided in people who are susceptible to hypotension or those taking specific anti-hypertensive medications. Other common side effects include flushing, headache and vision changes.
While sildenafil may not be the magic bullet for all lung diseases, it is clear that it has promising uses that go beyond erectile dysfunction.
Tyler PietreMD (Internal Medicine Physician), McMaster University, Dena ZeratkariAssistant Professor, Health Research Methods Evidence and Effects and Anesthesiology, McMaster UniversityAnd Jasmine MahiMD (Internal Medicine Resident) and PhD candidates (Focus on Geriatrics), Dalhousie University
This article is republished from Conversation Under Creative Commons license. read the original article,
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