In 1998, the introduction of Viagra opened a new chapter in the treatment of male erectile dysfunction.
After that, various medications have been introduced, and many treatments other than drugs have also come out one by one.
The most well-known medications taken before sexual activity belong to the phosphodiesterase type 5 inhibitor (PDE-5 inhibitor) category.
The four globally commonly used PDE-5 inhibitors are Sildenafil (Viagra), Vardenafil (Levitra), Tadalafil (Cialis), and Avanafil (Spedra).
In terms of efficacy, they are all quite good, with about 60-80% of people able to effectively improve their erection status and even successfully complete sexual intercourse.
Because they are taken before sexual activity, many people believe that these medications are only for emergency use and just "temporary solutions, not permanent cures”.
But is it really so?
In fact, according to research, this type of medication can increase the production of VEGF, leading to an increase in the amount of cGMP and proliferation of endothelial cells.
In animal experiments, long-term use of PDE-5 inhibitors can improve endothelial cell function, reduce vascular inflammatory factors, and protect the endothelial tissue of blood vessels.
It can significantly improve or prevent the intracavernous structural alterations caused by age, diabetes or surgical damage.
In the treatment of male erectile dysfunction, clinical studies have shown that continuous use of PDE-5 inhibitors on a daily basis can significantly improve erectile function and the peak systolic velocity (PSV) of penile cavernous arteries, compared to as-needed use.
For men undergoing low-intensity shockwave therapy (Li-SWT), combining daily low-dose Tadalafil 5mg (Cialis) with Li-SWT can yield better results than Li-SWT alone.
For men undergoing sexual function rehabilitation after radical prostatectomy, long-term use of PDE-5 inhibitors is an essential part of treatment, and is considered both standard and first-line therapy due to its efficacy, ease of use, good tolerability, excellent safety, and positive impact on quality of life.
In addition to treating erectile dysfunction, PDE-5 inhibitors have been shown to effectively treat benign prostatic hyperplasia and lower urinary tract symptoms (LUTS).
They can reduce smooth muscle tone of the detrusor, prostate, and urethra, and may also alter reflex pathways in the spinal cord and neurotransmission in the urethra, prostate, or bladder.
Furthermore, long-term treatment with PDE-5 inhibitors appears to increase blood perfusion and oxygenation in the lower urinary tract and may reduce chronic inflammation in the prostate and bladder.
A variety of PDE-5 inhibitors are currently available, and the aforementioned research results are not limited to a specific drug.
However, for the treatment of male erectile dysfunction, prostatic hypertrophy and lower urinary tract symptoms in the form of continuous daily use, only low-dose Tadalafil 5 mg daily tablets are approved by European Medicines Agency (EMA) and Taiwan FDA.
Summary of key points:
1. PDE-5 inhibitors (ED drugs) are not just for short-term use before sexual activity. Long-term use can significantly improve erectile function and can be used in combination with other ED treatments for better efficacy. They are also a standard first-line treatment for sexual function rehabilitation after prostate surgery.
2. PDE-5 inhibitors can also be used to treat benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). Low-dose Tadalafil 5mg daily tablet is the only PDE-5 inhibitor currently approved by the health department for daily use.
References:
https://uroweb.org/guidelines/management-of-non-neurogenic-male-luts/chapter/disease-management
The phosphodiesterase 5 inhibitor sildenafil stimulates angiogenesis through a protein kinase G/MAPK pathway
https://pubmed.ncbi.nlm.nih.gov/17226792/
Type 5 phosphodiesterase (PDE5) and the vascular tree: From embryogenesis to aging and disease
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333613/
in vitro treatment of dermal papillae with sildenafil induces VEGF and platelet derived growth factor A (PDGFA) secretion, increased dermal proliferation and neoangiogenesis
https://pubmed.ncbi.nlm.nih.gov/30292404/
Behr-Roussel, D., et al. Chronic sildenafil improves erectile function and endothelium-dependent cavernosal relaxations in rats: lack of tachyphylaxis. Eur Urol, 2005. 47: 87.
https://pubmed.ncbi.nlm.nih.gov/15582254/
Ferrini, M.G., et al. Vardenafil prevents fibrosis and loss of corporal smooth muscle that occurs after bilateral cavernosal nerve resection in the rat. Urology, 2006. 68: 429.
https://pubmed.ncbi.nlm.nih.gov/16904479/
Ferrini, M.G., et al. Long-term continuous treatment with sildenafil ameliorates aging-related erectile dysfunction and the underlying corporal fibrosis in the rat. Biol Reprod, 2007. 76: 915.
https://pubmed.ncbi.nlm.nih.gov/17287493/
Kovanecz, I., et al. Chronic daily tadalafil prevents the corporal fibrosis and veno-occlusive dysfunction that occurs after cavernosal nerve resection. BJU Int, 2008. 101: 203.
https://pubmed.ncbi.nlm.nih.gov/17888043/
Vignozzi, L., et al. Effect of chronic tadalafil administration on penile hypoxia induced by cavernous neurotomy in the rat. J Sex Med, 2006. 3: 419.
https://pubmed.ncbi.nlm.nih.gov/16681467/
The Effect of Combination Treatment With Low-Intensity Shockwave Therapy and Tadalafil on Mild and Mild-To-Moderate Erectile Dysfunction: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial. J Sex Med, 2022. 19: 106.
https://pubmed.ncbi.nlm.nih.gov/34866029/
Improved spontaneous erectile function in men with mild-to-moderate arteriogenic erectile dysfunction treated with a nightly dose of sildenafil for one year: a randomized trial
https://pubmed.ncbi.nlm.nih.gov/17187165/
Impact of Phosphodiesterase Type 5 Inhibitors on Endothelial Function
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2312340/
