Tadalafil belongs to a class of reversible phosphodiesterase-type 5 inhibitors. The medication is traditionally packaged in an oral pill and is available in a variety of dosages: 2,5 mg, 5 mg, 10, mg, 20 mg. In its generic versions, tadalafil can be available at other dosages as well.
While envisioned, manufactured and marketed as a treatment for ED in men primarily, tadalafuil has shown efficacy in treatment of benign prostatic hyperplasia and granted an authorization as a treatment for this condition as of 2012. While the accurate place of tadalafil’s in BPH therapy is yet to be established, there are positive indications that tadalafil can become the primary option for treating the condition among all available on a today’s pharmaceutical market.
The summary of evidence of treatment of BPH with tadalafil
The available studies that were conducted to establish the efficacy of treatment of BPH in men show the following positive results: A large group of men were trialed with tadalafil in a classic, double blind, placebo controlled, dose finding study. For twelve weeks, the group of men were treated with placebo or tadalafil (5 mg). The findings upon the end of the treatment showed that daily 5 mg dosage of tadalafil administered improved the lower urinary tract symptoms compared to those with placebo on average at 2.6 points according to the recognized world-wide prostate symptoms score coefficient. It should be noted that while the primary benefits of administering tadalafil were observed within the first twelve weeks of treatment, these were maintained to a smaller degree for a larger timeframe (six months to twelve month).
Is there a connection between erectile dysfunction and BHP?
Erectile dysfunction and lower urinary tract symptoms, where BHP belongs, in general considered to be very prevalent conditions that are affecting the overall quality of a male’s life negatively. While these two conditions had been considered separated from one another for a significant period of time, however, due to the increasing number of clinical researches and gathered data, the two conditions have become linked from the point of view of modern medicine as they share several comоrbidies and also have a similar impact on one’s lifestyle.
Major shared pathways between ED and BHP
There are four major ways on evaluating how pathways are shared between ED and BPH.
- The shared impairness of the synthase of nitric dioxide while in the endothelium of the pelvic area. The latter includes the prostate, the bladder, and the smooth muscles of the penis.
- A known increase of Rho-kinase activation which in its turn manifests in the decreased relaxation in muscles. As a result, the outlet resistance of the bladder gets magnified while a possibility to get a healthy erection gets lower.
- There is a connection between an autonomic hyperactivity as well as accompanied metabolic syndrome effects on the growth of the prostate and erectile dysfunction.
- Consider atherosclerosis as a common precursor for BHP and erectile dysfunction. Atherosclerosis is known to significantly reduce nitric dioxide production as well as Rho-kinase activation and usually causes the overall loss of smooth muscles from the area of the bladder detrusor and prostate fibrosis commonly linked with the overall decreased bladder compliance.
To add, all four ways are accompanied by the impairment of vascular function.
What is the clinical evidence of effects of tdalafil on the common pathways of erectile dysfunction and BPH?
There are two important mechanisms that play role in decreasing the tension in smooth muscles of the bladder as well as the penis: the reversal of norepinephrine and endiothelin tissue constriction and an anti-proliferative effect on muscle cells in the prostate and in the bladder.
- Tadalafil, as PDE5 inhibitor has greater activity when compared to sildenafil citrate or vardanafil in the overall relaxation level of the above mentioned smooth muscles. Across the family of PDE5 inhibitors, only tadalafil showed results in relaxation of the smooth muscles in the bladder and prostate of more than fifty percent on the pre-contracted strips.
- Tadaladil causes an inhibitory effect on nitric оxide among ion channels across afferent neurons (sensory pathways) as well as on afferent activity of nerves in the bladder.
- Tadаlafil have a potential of inhibiting in vitro activity of PDE5, which is manifested in the vesicular-deferential arteries and increased oxygenation into the prostate tissue.
- Tаdalafil increases prostatic blооd perfusion.
- Tаdalafil lessens the amount of expression of a variety of inflammatory markers and has a potential of reducing atherosclerotic overall damage as well as inflammation by way of decreasing leukocyte recruitment significantlyю
Tаdalafil’s mechanism of action in relation to BHP:
- Upregulating nitric oxide/ cycle GMP activity
- Downregulating Rho-kinase activity
- Modulating autonomous nervous system over-activity and afferent nerve activity
- Increasing pelvic perfusion and reducing ischemia
- Reducing inflammation
Is taking tadalafil safe for patients with BHP?
The clinical studies have shown that tadalafil is a very safe treatment.
There are side effects of taking tadalafil which include:
- Mild headache
- Nasal congestion
- Face flushing
- Mild back pain
The incidents of these are varied from 1 percent to 3 percent among the patients in the control group.
Is it safe to combine α-adrenergic antagonist with tadalafil?
The studies have shown that all patients who alpha-blockers with tadalafil 5 mg were stable. It is generally considered to be a healthy combination of two powerful medicines. However, the further study needs to be done for the specific type of alpha-blockers, most notably those taking doxazosin and other nonuro-selective alpha-blockers. There is some evidence that men who take these when combined with tadаlafil treatment show increased hemodynamic signs and symptoms.