Erectile dysfunction (ED) means the inability to attain or maintain a penile erection sufficient for intercourse, which is observed for three or more months. In multicenter studies, it’s been determined that the incidence of ED, especially in elderly men, is connected with many risk factors, often related: age, diabetes mellitus, atherosclerosis, hypertension, obesity, smoking, alcohol abuse, lifestyle sedentary, depression and relatively low incidence education. In line with the results of the long-term Massachusetts Male Aging Study (MMAS), diabetes mellitus is a major risk factor for ED: 35-75% of men with diabetes are identified as having ED. ED can also be an early sign of atherosclerosis and cardiovascular system disease.
Microangiopathies lead to dysregulation of the nitric oxide (NO) system. Formed in nerve endings and endothelial cells during sexual arousal, NO activates the guanylate cyclase system, resulting in an increase in the concentration of cyclic guanosine monophosphate (cGMP). cGMP activates a specific protein kinase, consuming which the calcium concentration inside the cell decreases and the smooth muscle cells of the arteries relax, that leads to an increase in blood flow to the cavernous bodies and the occurrence of a ‘erection.
In the cavernous tissue, under the action of a specific phosphodiesterase type 5 (PDE-5), cGMP is converted into the inactive 5′-guanosine monophosphate. With insufficient production of NO by ischemic or damaged endothelium, the concentration of cGMP in vascular smooth muscle cells decreases, because of which there is no increase in blood flow to the corpora cavernosa and effective erection does not occur. However, the tissue concentration of cGMP is regulated by both the rate of synthesis and the rate of its destruction by PDE-5. Inhibition of cGMP degradation by phosphodiesterase type 5 inhibitors results in an increase in its concentration in smooth muscle cells, which promotes erection.
Treatment of erectile dysfunction
Most doctors start ED treatment with PDE5. Three PDE type 5 inhibitors have been approved for medical use in Russia: sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), the pharmacokinetics which differ significantly. The half-life for sildenafil and vardenafil is 4 hours, for tadalafil – 17.5 hours. The equilibrium concentration of tadalafil is reached on the 5th day with daily intake and exceeds the original 1.6 times, so the drug does not have the ability to accumulate, which allows one to use it constantly.
Recently, many studies have been completed showing that the constant use of tadalafil not only plays a part in the maintenance of erectile function, but can also be used to treat lower urinary system symptoms (LUTS). In most men over 50 with ED, the most typical disease is benign prostatic hyperplasia (BPH), combined with LUTS (frequent urination, need for abdominal tenderness when urinating, inability to delay voiding, nocturia , incomplete bladder emptying and low urine flow).
KE Andersson, in an assessment article, discusses the chance of using tadalafil for the treatment of LUTS occurring in BPH and discusses at length the pathophysiological mechanisms of the development of LUTS. The relationship between your development of LUTS in BPH and ED has been identified in other studies. The outcomes of six completed studies on the use of tadalafil for the treating ED and LUTS indicate: tadalafil when taken continuously at doses of 2.5; five; 10 and 20 mg do not affect urodynamic parameters: maximum flow rate, detrusor pressure during miction; in addition, the increase in the amount of prostate antigen when taking tadalafil is comparable to taking placebo and is approximately 0.2 mg / ml / year. However, dosaggio cialis 40 mg of
An interesting multicenter, double-blind, randomized, placebo-controlled study of taking tadalafil 5mg once a day, which took into account the standard of the partner’s sex life. The principal assessment criterion because of this study was the change between baseline and endpoint erectile function scores, including International Index of Erectile Function (ICEF), Quality of Sex Life (SQoL), and Intercourse Profile. (SQoL), Sexual Life Quality Questionnaire (SLQQ) ). The partners were split into groups: patients in a single group received placebo (n = 78), the other received tadalafil 5 mg once a day (n = 264) for 12 weeks. The responses of the men and their partners were collected through the entire study. Compared to placebo, the tadalafil group showed significant improvement in erection efficiency (p < 0.001), including changes in IIEF, two- and three-question ratio profiles. Furthermore, when taking tadalafil 5 mg once each day, the quality of sexual life of men and their partners SQoL was significantly higher than in the placebo group (p < 0.001).
Tadalafil unwanted effects discussion
Regarding the the increase in the amount of studies specialized in the constant usage of tadalafil in the clinic, there exists a discussion about the side effects and complications connected with taking the drug. In his review article, D. Pushkar et al. provides examples of multicenter, randomized, placebo-controlled studies of safe daily tadalafil therapy in men with ED. In one such study, 184 patients took tadalafil in doses of 5 and 10 mg each day, of which only three men stopped taking the drug – in one case because of headaches and dizziness, and in two cases due to cause of abdominal pain.
Many men with ED have concomitant pathology of the heart; the safety of therapy in these patients is particularly relevant. A multicenter study conducted in 36 clinics evaluated the dynamics of cardiovascular diseases when taking tadalafil at a dose of 2 to 50 mg each day or up to 3 times a week. The analysis included 12,487 men (mean age 55 years) with ED treated with tadalafil followed up by 5771 patient-years and 2047 men (mean age 56 years) in the placebo group followed up by 460 patient-years. The analysis excluded patients with premature ejaculation, penile anatomical deformities and prostheses, secondary ED (eg, hypogonadism), unstable angina, myocardial infarction (before 3 months), with systolic blood circulation pressure > 170 or <90 mm Hg. Art. and diastolic blood pressure> 100 or <50 mm Hg. Art. Nitrates have been found in exceptional cases. The duration of the analysis ranged from 6 to 27.2 months.
At the beginning of the study, the structure of concomitant diseases was as follows: arterial hypertension – 31%, diabetes – 21%, hyperlipidemia – 17%, cardiovascular system disease – 5%. Cases of adverse development of cardiovascular events (CVTEAE) were retrospectively analysed: myocardial infarction, sudden cardiovascular and cerebrovascular death. Additionally, patients were divided into risk groups, including obesity, smoking, and over 65 years.
CVTEAEs per 100 patient-years were calculated by dividing the number of patients with this particular disease by patient-year (PY) exposure and multiplying by 100. The incidence of myocardial infarction (MI) per 100 patient-years was calculated by dividing the quantity of patients with MI by the PY exposure and multiplying by 100. Patient exposure-years were determined for each patient and calculated from the date of randomization to the date of completion. The precise 95% confidence intervals for CVTEAE were calculated using the Poisson distribution. Across all studies, CVTEAEs in tadalafil-treated patients were 0.40/100 patient-years (5771 patient-years of exposure) and 0.43/100 patient-years in the placebo-controlled groups (460 patient-years of exposure ).
The data show that the incidence of serious cardiovascular events through the first stages of tadalafil therapy (i.e., 0 to 3 months) is comparable to the incidence of CVTEAE during 27.2 months of therapy. In patients taking tadalafil, the incidence of serious cardiovascular events (CVTEAE) ranged from 0.17/100 to 0.54/100 patient-years in placebo-controlled and open-label studies. Incidence rates of CVTEAE were comparable in men with erection dysfunction taking tadalafil to those in patients receiving placebo.
Medical research results
In conclusion, it should be said that the drug tadalafil, which is successfully used for the treatment of ED on demand, can be utilized continuously once each day for several months and even years. Evaluations of continuous use of tadalafil are high, especially when taking into consideration the interests of both partners and the side effects are comparable to those of placebo. The inclusion of tadalafil in the therapy of LUTS in BPH looks promising, however, further studies are essential to research the interaction of the drug with ?-1-adrenergic blockers and 5?-reductase blockers, confirmed by working experience.
