In vitro effects of PDE5 inhibitors sildenafil, vardenafil and tadalafil on isolated human ureteral smooth muscle: a basic research approach

Optimum combined MET according to tolerability with efficacy, Silodosin Tadalafil versus Silodosin Vardenafil for distal ureteric stone: a prospective, double blinded, randomized clinical trial

OBJECTIVES

To determine the optimum combination therapy of Silodosin-Tadalafil versus Silodosin-Vardenafil in terms of both tolerability and efficacy for the management of distal ureteric stones.

METHODS

This prospective, double blinded, randomized clinical trial included 140 patients with distal ureteric stones, randomized into two groups: Group I (n = 67) received Silodosin 8 mg once daily combined with Tadalafil 5 mg once daily, and Group II (n = 68) received Silodosin 8 mg once daily combined with Vardenafil 10 mg once daily. The primary outcome was the tolerability of the combination therapies, assessed through the incidence of adverse events. Secondary outcomes included stone expulsion rate, expulsion time, and the need for analgesics.

RESULTS

Both combination therapies demonstrated similar efficacy, with no significant differences in stone expulsion rate (70.1% vs. 67.6%, P = 0.754), expulsion time (19 ± 3 days for both groups, P = 0.793), and analgesic requirements (P > 0.05). However, the Silodosin-Tadalafil combination showed a significantly lower occurrence of adverse events, with notable differences in headache (23.9% vs. 57.4%, P < 0.001), dizziness (32.8% vs. 60.3%, P = 0.001), and gastrointestinal upset (9% vs. 66.2%, P < 0.001), and other adverse effects. The overall occurrence of any adverse event was significantly lower in the Silodosin-Tadalafil group (88.1% vs. 98.5%, P = 0.017).

CONCLUSIONS

Both Silodosin-Tadalafil and Silodosin-Vardenafil therapies are effective in managing distal ureteric stones. However, the Silodosin-Tadalafil combination is associated with a significantly lower incidence of adverse events, making it a more tolerable option for patients.

Drugs to affect the smooth musculature of the human ureter - an update with integrated information from basic science to the use in medical expulsion therapy (MET)

PURPOSE

Urolithiasis and symptomatic ureterolithiasis represent diseases known to be on the increase in most westernized countries. The present article aims to give an overview on some drug principles assumed to target signalling systems involved in modulating ureter smooth muscle contractility and to present background to their potential use or prospects in ureter stone disease.

METHODS

The article reviews drugs that have been evaluated over the last decades in vitro, in vivo and/or in clinical settings with regard to their properties to achieve spontaneous passage of (distal) ureteral stones and relieve colic pain. Among these drugs are alpha- and beta-adrenoceptor antagonists, calcium channel blocking agents, Rho kinase inhibitors, nitric oxide (NO) donor drugs, selective inhibitors of cyclic nucleotide phosphodiesterase enzymes (PDEs), as well as potassium channel openers.

RESULTS

Based on the recent scientific information on agents targeting different pathways, antagonists of alpha 1-adrenoceptors, inhibitors of the PDE isoenzymes PDE4 and PDE5 (affecting cyclic AMP- or NO/cyclic GMP-mediated signals that facilitate relaxation of ureter smooth muscle), as well as the combination of certain drugs (for example, PDE5/PDE4 inhibitor plus alpha 1-AR antagonist) seem to be intriguing pharmacological approaches to medical expulsion therapy (MET) in the overall population of patients.

CONCLUSION

While NO donors, calcium channel antagonists and potassium channel openers may be limited for further development for medical expulsion therapy (MET) due to their systemic effects and a lack of effect on stone clearance, Rho kinase inhibitors should be explored further as a future pharmacological principle in ureteral stone disease.

Inhibition of PDE-4 isoenzyme attenuates frequency and overall contractility of agonist-evoked ureteral phasic contractions

The aim of this study was to investigate the functional role of phosphodiesterase enzymes (PDE) in the isolated porcine ureter. Distal ureteral strips were mounted in organ baths and pre-contracted with 5-HT (100 μM). Upon generation of stable phasic contractions, PDE-4 and PDE-5 inhibitors were added cumulatively to separate tissues. PDE-4 inhibitors, such as rolipram (10 nM and greater) and roflumilast (100 nM and greater), resulted in significant attenuation of ureteral contractile responses, while a higher concentration of piclamilast (1 μM and greater) was required to induce a significant depressant effect. The attenuation effect by rolipram was abolished by SQ22536 (100 μM). PDE-5 inhibitors, such as sildenafil and tadalafil, were not nearly as effective and were only able to suppress the 5-HT-induced contractions at higher concentrations of 1 μM. Rolipram significantly enhanced the depressant effect of forskolin, while sodium nitroprusside-induced attenuation of contractile responses remained unchanged in the presence of tadalafil. In summary, our study demonstrates that PDE-4 inhibitors are effective in attenuating 5-HT-induced contractility in porcine distal ureteral tissues, while PDE-5 inhibitors are less effective. These findings suggest that PDE-4 inhibitors, such as rolipram, may hold promise as potential therapeutic agents for the treatment of ureteral disorders attributable to increased intra-ureteral pressure.

Is low-dose tadalafil better than tamsulosin? A randomized controlled trial in shockwave lithotripsy for solitary upper tract calculi

OBJECTIVE

To ascertain whether low-dose tadalafil (5 mg) is more efficient than tamsulosin (0.4 mg) in facilitating calculus expulsion in those receiving extracorporeal shockwave lithotripsy for solitary upper urinary tract calculi.

PATIENTS AND METHODS

This was a triple-blinded, prospective, superiority, randomized controlled, single-centre trial. A total of 250 patients with solitary renal or ureteric calculus measuring 6-24 mm were randomized (1:1) to receive either 0.4 mg tamsulosin or 5 mg tadalafil daily for 30 days or until calculus clearance, whichever was earlier.

RESULTS

There was no difference in the primary outcome, namely, calculus expulsion rate at 30 days (tamsulosin vs tadalafil, n (%) 99 [81.1%] vs 98 [80.3%] respectively, 95% confidence interval = 0.8% [-9.0, 10.7], P = 0.874). Similarly, a lack of difference was also noted in the secondary outcome, number of days to expulsion (tamsulosin vs tadalafil, geometric mean [SD] 13.59 [2.39] vs 13.74 [2.39] respectively, P = 0.928). Four patients discontinued the drug due to adverse drug reactions in the tadalafil group.

CONCLUSIONS

Low-dose tadalafil is not superior to tamsulosin in improving calculus expulsion when used as an adjunct to shockwave lithotripsy. In this study, we also noted that tadalafil was less tolerated.

Efficacy of tamsulosin versus tadalafil as medical expulsive therapy on stone expulsion in patients with distal ureteral stones: A randomized double-blind clinical trial

Purpose:

To compare the effects of tadalafil, tamsulosin, and placebo as a medical expulsive therapy (MET) for distal ureteral calculi.

Materials and Methods:

This prospective randomized double-blind clinical trial was conducted on 132 renal colic patients with distal ureteric stones (≤10mm) over a period of 12 months. Patients were randomly divided into three groups. Patients in group A received tamsulosin 0.4mg, in group B received tadalafil 10mg, and in group C received placebo. Therapy was given for a maximum of 4 weeks. The rate of stone expulsion, duration of stone expulsion, the dose and the duration of nonsteroidal anti-inflammatory drugs (NSAIDs), analgesic use, and adverse effects of drugs were recorded.

Results:

Demographic profiles were comparable between the 3 groups. Although the stone expulsion rate in group A (72.7%) was higher in comparison to group B(63.6%) and group C(56.8%), it was not considered statistically significant (P=0.294). Shorter mean time to stone expulsion was significantly observed in group A (17.75±75), than group B(21.13±1.17) and group C(22.25±1.18) (P=0.47). The mean number of analgesic use was 9.8±5.09 days in group A, 14.6±7.9 days in group B, and 12.6±22.25 days in group C, this difference was significant (P=0.004). The analgesic requirement (doses of NSAIDs and pethidine) in group A was significantly lower than other groups (P<0.05). Also, patients in group A reported fewer headaches compared to other groups (P=0.011).

Conclusion:

Tamsulosin as medical expulsive therapy is more effective for distal ureteric stones with less need for analgesics and less stone expulsion time than tadalafil.

Current and emerging pharmacological targets for medical expulsive therapy

The primary goals of medical expulsive therapy are to increase the rate of stone expulsion along the ureter to avoid ureteral obstruction and reduce ureteral colic and thus avoid the need for surgical and more invasive interventions. This review focussed on the findings from in vivo and in vitro animal and human studies that have investigated the pharmacological mechanisms controlling ureteral motility and their translation to current and potentially new clinically used drugs for increasing the rate of stone expulsion along the ureter. The complicated contractility profile of the ureter, which alters with age, tissue segment region, orientation and species contributes to the difficulty of interpreting studies on ureteral pharmacology, which translates to the complexity of discovering ideal drug targets for medical expulsive therapy. Nevertheless, the current drug classes clinically used for patients with stone lodgement include α₁ -adrenoceptor antagonists, calcium channel blockers and NSAIDS, whilst there are promising targets for drug development that require further clinical investigations including the phosphodiesterase type 5 enzyme, β-adrenoceptors and 5-HT receptors.

Efficacy and safety of silodosin, vardenafil versus silodosin in combination with vardenafil as a medical expulsive therapy for distal ureteric stones: a prospective randomized double-blind study

Background

Urolithiasis is considered one of the most common diseases in urological practice. Its prevalence is about 1% to 15% with 30 years old as the peak age of incidence. Medical expulsive therapy (MET) has been used as a conservative treatment for patients with ureteral stones. Nitrergic fibers have been identified to have a relaxant effect on the distal ureteral smooth musculature. The objective of our study was to evaluate the efficacy and safety of the combination of silodosin and vardenafil as a medical expulsive therapy in comparison with each drug alone.

Methods

One hundred and two male patients with uncomplicated distal ureteric stone 6–10 mm were enrolled in the study. The patients were randomly divided into 3 equal groups, and each one consists of 34 patients. Group I received silodosin 8 mg once daily, group II vardenafil 5 mg once daily and group III combination of silodosin 8 mg and vardenafil 5 mg once daily. The treatment was given for all the patients until stone expulsion or a maximum of 4 weeks. The primary endpoint was the stone expulsion rate, and the secondary endpoints were time to stone expulsion, number of hospital visits for pain, amount of analgesic required and side effects associated with MET.

Results

Our study showed that the stone expulsion rate was higher in combination = 90.0% than silodosin = 76.7% and vardenafil groups = 60.0% (P = 0.025), the time to stone expulsion was significantly shorter in combination = 11.23 ± 3.14 than silodosin = 12.50 ± 1.66 and vardenafil groups 14.67 ± 1.24 days (P < 0.01), the number of hospital visits for pain was statistically significant between the three groups (silodosin 1.35 ± 0.9, vardenafil 1.65 ± 1.09 and combination groups 1.02 ± 0.80) (P = 0.038) and lesser amount of analgesic required in combination 313.6 ± 2.85.5 than silodosin 613.44 ± 483.62 and vardenafil groups 716.97 ± 685.3 (P = 0.008). There was no significant difference among the studied groups as regards the drugs side effects except for retrograde ejaculation (silodosin and combination = 86.7% vs vardenafil groups = 0.0%) (P < 0.05) and increased erection (combination = 26.7%, vardenafil = 23.3% and silodosin groups = 0%) (P = 0.010).

Conclusion

The prescription of vardenafil in combination with silodosin is safe and more effective than silodosin or vardenafil alone as a MET.

Efficacy of Tamsulosin plus Tadalafil versus Tamsulosin as Medical Expulsive Therapy for Lower Ureteric Stones: A Randomized Controlled Trial

Introduction

Urolithiasis is one of the common disorder with which about 1/5^th is found in the ureter, of which 2/3^rd is seen in the lower ureter. Medical expulsive therapy is one of the routine modalities of treatment which uses various drugs acting on the ureter smooth muscle by different mechanism. We aim to compare the efficacy of combination vs. single drug.

Methods

This randomized controlled trial was done in 176 consecutive patients over a period of six months (March 2019 to August 2019) in Department of Urology and Kidney Transplant Surgery, Tribhuvan University Teaching. Participants were divided into two groups (Group A, tamsulosin plus tadalafil, and Group B, tamsulosin) from computer-generated random numbers. Therapy was continued for a maximum of 3 weeks. Stone expulsion rate, time to stone expulsion, analgesic use, number of colic and emergency room visits for pain, early intervention, and adverse effects of drugs were recorded.

Results

Among 176 patients who were enrolled in study, 7 were lost to follow-up, and 5 people required immediate intervention. There was a significant higher stone passage rate in group A than group B (64 vs. 50; P=0.025) and shorter expulsion time (1.66 vs. 2.32 weeks P=0.001) and less number of emergency room visits and colic episodes. No significant side effects were noted during study.

Conclusion

Tamsulosin plus Tadalafil is more effective than tamsulosin with early passage of stone and decreased number of colic episodes and emergency visits without significant side effects for lower ureteric calculi of 5 mm to 10 mm.

Efficacy and safety of PDE5-Is and α-1 blockers for treating lower ureteric stones or LUTS: a meta-analysis of RCTs

BACKGROUND

Lower ureteric stones and lower urinary tract symptoms are common in urology.Drug treatment is one of standard therapy,but the efficacy was controversial.Thus we aimed to investigate the efficacy and safety of monotherapy or combination therapy of adrenoceptor1 blockers and phosphodiesterase5 inhibitors for treatment.

METHODS

Randomized controlled trials up to November 2016 were retrieved from PubMed, the Cochrane Library, Web of Science and Embase. A total of 17 studies were included. We analyzed data through random or fixed effect models. The heterogeneity between studies was assessed by the I² test statistic.

RESULTS

As for lower ureter stones, our analysis demonstrated tadalafil had a significantly lower incidence of abnormal ejaculation than adrenoceptor1 blockers (2.31 95%CI 0.22to0.84, P = 0.01),while combination therapy had a higher expulsion rate (2.49 95%CI 1.44to4.29, P = 0.001) and shorter expulsion time (- 1.98 95%CI -3.08to0.88, P = 0.0004) than tamsulosin. As for lower urinary tract symptoms, our analysis indicated adrenoceptor1 blockers was more effective than phosphodiesterase5 inhibitors on decreasing International Prostate Symptom Score (1.96 95%CI 0.03to3.89, P = 0.05) and Post-Void Residual (9.41 95%CI 1.40to14.41, P = 0.02) and phosphodiesterase5 inhibitors showed a greater effect than adrenoceptor1 blockers on improving Erectile Dysfunction (2.23 95%CI 1.24to3.22, P<0.0001).Combination therapy had a significantly better effect on International Prostate Symptom Score (1.47 95%CI 1.25to1.69, P<0.0001), Maximum flow rate (0.87 95%CI 0.71to1.04, P<0.0001), Post-Void Residual (10.74 95%CI 3.53to17.96,P = 0.004) and Quality of life (0.59 95%CI 0.22to0.97, P = 0.002) but was associated with higher incidences of adverse events (3.40 95%CI 1.82to6.36, P = 0.0001) than adrenoceptor1 blockers. Combination therapy had a significantly better effect on International Prostate Symptom Score (4.19 95%CI 3.34to5.04, P<0.0001), Maximum flow rate (1.86 95%CI 1.32to2.39, P<0.0001), Post-Void Residual (22.58 95%CI 9.13to36.04, P = 0.001) and Quality of life (0.68 95%CI 0.37to1.00, P<0.0001) without higher incidences of adverse events than PDE5-Is.

CONCLUSIONS

In conclusion, this meta-analysis suggested combination therapy had a best efficacy of therapy for lower ureteric stones or lower urinary tract symptoms correlated with benign prostatic hyperplasia than monotherapy. Adrenoceptor1 blockers was more effective than phosphodiesterase5 inhibitors on International Prostate Symptom Score and Post-Void Residual. Both monotherapy and combination therapy were safe.

Chinese herbal medicine to treat urolithiasis in a patient with right flank pain and hematuria: A case report

OBJECTIVE

Urolithiasis is a common medical condition affecting the urinary tract. Typical symptoms reported by patients include colic pain and hematuria. Some patients may undergo surgical intervention or lithotripsy to remove the stones. In this case, we demonstrated that Chinese herbal medicine (CHM) was an effective modality to remove stones in a patient with urolithiasis.

CLINICAL FEATURES AND OUTCOME

A 47-year-old man suffered from right flank pain and hematuria for three months and was diagnosed with an upper third ureteral stone obstruction with right hydronephrosis. He had received extracorporeal shock wave lithotripsy (ESWL) three times before his first CHM visit, but it was unsuccessful. Therefore, he sought CHM for further intervention. His symptoms subsided, and the image study showed complete removal of the ureteral stone after regular therapy with Zhi Bai Di Huang Wan () combined with Lygodii spora (), Curcumae radix (), Endothelium Corneum Gigeriae Galli (), Lysimachiae herba (), Orthosiphon stamineus () for approximately four months. Neither complications nor side-effects were noted during the CHM treatment.

CONCLUSIONS

In this case, we concluded that CHM may be an effective alternative therapy for the treatment of ureteral stones, and furthermore, may also be applied as an option to salvage failed ESWL procedures.

Comparative efficacy of tamsulosin versus tadalafil as medical expulsive therapy for distal ureteric stones

Objective:

The objective of this study was to compare the relative efficacy of tamsulosin and tadalafil as medical expulsive therapy for distal ureteric stones.

Patients and Methods:

This was a prospective study performed between December 2014 and February 2016. A total of 123 adult patients (>18 years of age) presenting with distal ureteric stones sized 6–10 mm were randomized to treatment with tamsulosin 0.4 mg once daily (Group A) or tadalafil10 mg once daily (Group B). Therapy was given for a maximum of 4 weeks. The stone expulsion rate was the primary endpoint. Time to stone expulsion, number of colic episodes, analgesic use, number of hospital visits for pain, endoscopic treatment, and adverse effects of the drugs were noted. Statistical analyses were done using Fisher's exact test and Chi-square test.

Results:

A total of 61 patients were included in tamsulosin group and 62 patients in tadalafil group. A statistically insignificant difference was found for stone clearance rate between both groups as a whole (Group A-73.77%, Group B-69.35%, P = 0.690) as well as when we considered both subgroups (A1-78.05%, B1-75.0%, P = 0.802; A2-65.0%, B2-55.6%, P = 0.741). All the primary and secondary outcome measures were more in favour of stones ≤8 mm size than stones >8 mm size. No statistical difference was found for adverse drug effects except for retrograde ejaculation, which was significantly high in tamsulosin group (P < 0.001).

Conclusion:

This study showed that although tamsulosin is more effective for stone clearance than tadalafil, but this difference was not significant (P = 0.690).

Safety and efficacy of silodosin and tadalafil in ease of negotiation of large ureteroscope in the management of ureteral stone: A prosective randomized trial

OBJECTIVE

To evaluate the safety and efficacy of silodosin and tadalafil in ease of negotiation of large size ureteroscope (8/9.8 Fr) in the management of ureteral stone.

MATERIAL AND METHODS

Between June 2015 and May 2016, 86 patients presented with ureteral stone of size 6-15 mm were on consent randomly assigned to 1 of 3 outpatient treatment arms: silodosin (Group A), tadalafil (Group B), and placebo (Group C). After two weeks of therapy 67 patients underwent ureteroscopy, and ureteral orifice configuration, ureteroscopic negotiation, ureteral dilatation, operating time, procedural complication and drug related side effects were noted in each group.

RESULTS

Ureteral negotiation was significantly better in Groups A (73.9%) and B (69.6%) as compared to Group C (38.1%) (p<0.01). Statistically significant difference was noted in the requirement for dilatation in Group C (71.4%) as compared to Groups A (26.1%) and B (39.1%) (p<0.01). Ureteral orifice was found to be more dilated in Groups A (69.6%) and B (60.9%) as compared to Group C (28.6%). Mean operating time was statistically lower in Groups A (35.2 min) and B (34.91 min) as compared to Group C (41.14 min) (p<0.01).

CONCLUSION

Both silodosin and tadalafil not only relax ureteral smooth muscle but also help in forward propagation of large size ureteroscope (8/9.8 Fr) without any significant risk of adverse events.

Risks of flexible ureterorenoscopy: pathophysiology and prevention

Currently, indications for flexible ureterorenoscopy (fURS) are expanding, mainly due to technological advancements. Although data from clinical series definitely presents fURS as a safe procedure, serious complications including sepsis and ureteral lesions do occur. These complications seem to be a result of the unique elements of fURS, ureteral access and irrigation, pushing normal upper urinary tract physiology into pathophysiological processes, including intrarenal/pyelo-veneous backflow and ureteral contractions, potentially resulting in septic, haemorrhagic and ureteral lesional complications. Knowledge on normal upper urinary tract physiology are crucial for understanding how these harmful effects of fURS may be avoided or minimized. The pathophysiology of intrarenal pressure increases and ureteral access will be discussed as a basis for understanding preventive measures. Role of antibiotics, ureteral access sheaths, safty guidewires, pain medication, prestenting and pharmacologic modulation of pyeloureteral dynamics are reviewed from a pathophysiological perspective.

Tadalafil Facilitates the Distal Ureteral Stone Expulsion: A Meta-Analysis

OBJECTIVE

To assess the efficacy and safety of tadalafil in facilitating the spontaneous passage of distal ureteral stones.

METHODS

The relevant studies were identified by searching MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials up to November 2016. Randomized controlled trials evaluating effects of tadalafil for distal ureteral stones were included.

RESULTS

Six publications involving 921 patients were included. Compared with tamsulosin monotherapy, tadalafil monotherapy or combined with tamsulosin has a significantly higher stone expulsion rate (relative risk [RR], 1.16; 95% confidence interval [CI], 1.05 to 1.29; p = 0.004; RR, 1.24; 95% CI, 1.09 to 1.42; p = 0.001, respectively) and shorter time to stone expulsion (mean difference [MD], -1.33 days; 95% CI, -2.44 to -0.23; p = 0.02; MD, -1.98 days; 95% CI, -3.08 to -0.88; p = 0.0004, respectively). Statistically significant differences were noted in pain episodes and analgesic use in favor of group tadalafil alone compared to group tamsulosin alone. The analgesic use was significantly lower in the combined group than in the tamsulosin alone group. Although the occurrence of drug-related adverse events in the tadalafil alone or combined with tamsulosin was higher than that in the use of tamsulosin-alone group, the most common adverse events were mild and tolerable.

CONCLUSIONS

Our study suggested that medical expulsive therapy for the distal ureteral stones using tadalafil alone or combined with tamsulosin is safe, efficacious, and well tolerated.

Inhibition by tadalafil of contractility of isolated nonpregnant human myometrium

Objective:

To investigate the inhibitory effect of tadalafil on the contractility of isolated nonpregnant human myometrium.

Materials and Methods:

The ability of tadalafil (25, 40, and 63 μM) to inhibit 55 mM KCl-induced contractility of isolated nonpregnant human myometrium was studied. The ability of the ATP-sensitive potassium channel blocker glibenclamide (10 μM) and the calcium-sensitive potassium channel (BKCa) blocker iberiotoxin (100 nM) to reverse the inhibitory effect of 40 μM tadalafil on 55 mM KCl-induced myometrial contractility was also studied.

Results:

Tadalafil produced a concentration-dependent inhibition of myometrial contractility that was statistically significant at 40 and 63 μM concentrations of tadalafil. The inhibition by tadalafil of myometrial contractility was statistically significantly reversed by the concurrent administration of glibenclamide and iberiotoxin.

Conclusions:

These results suggest that tadalafil inhibits human myometrial contractility by opening ATP-sensitive potassium channels and BKCa channels. The opening of these channels could have been due to the action of raised intracellular levels of cGMP due to inhibition of PDE-5 by tadalafil. The results suggest that tadalafil could be investigated for use in clinical conditions requiring relaxation of the myometrium.

Efficacy of phosphodiesterase type 5 inhibitors for the treatment of distal ureteral calculi: A systematic review and meta-analysis

PURPOSE

To determine the efficacy of phosphodiesterase type 5 inhibitors (PDE5i) as medical expulsive therapy (MET) for the treatment of distal ureteral calculi.

MATERIALS AND METHODS

A search strategy was conducted in the MEDLINE, CENTRAL, and Embase databases. Searches were also conducted in other databases and unpublished literature. Clinical trials were included without language restrictions. The risk of bias was evaluated with the Cochrane Collaboration's tool. An analysis of random effects due to statistical heterogeneity was conducted. The primary outcome was the expulsion rate of the distal ureteral calculus in 28 days. The secondary outcomes were the time to expulsion, side effects of treatment, and amount (mg) of nonopioid analgesia. The measure of the effect was the risk difference (RD) with a 95% confidence interval (CI). The planned interventions were PDE5i vs. placebo, tadalafil vs. placebo, and tadalafil vs. tamsulosin.

RESULTS

Four articles were included in the qualitative and quantitative analysis. Records of 580 patients were found among the four studies. A low risk of bias was shown for the majority of the study items. The calculi expulsion rate had an RD of 0.26 (95% CI, 0.15-0.37) and a less prolonged expulsion as a secondary outcome with a mean difference of -4.39 days (95% CI, -6.69 to -2.09) in favor of PDE5i compared with the placebo. No significant difference was found for these outcomes when comparing tadalafil with tamsulosin.

CONCLUSIONS

Compared with a placebo, PDE5i could be effective as MET for the treatment of distal ureter calculi.

Tamsulosin versus tadalafil as a medical expulsive therapy for distal ureteral stones: A prospective randomized study

PURPOSE

This study aimed to compare the safety and efficacy of tamsulosin and tadalafil as medical expulsive therapy for distal ureteral stones.

MATERIALS AND METHODS

This prospective randomized study was conducted at the Department of Urology of Bir Hospital over a period of 12 months in patients with distal ureteral stones sized 5 to 10 mm. Patients were randomly divided into 2 groups: group A received tamsulosin 0.4 mg and group B received tadalafil 10 mg at bedtime for 2 weeks. Stone expulsion rate, number of ureteric colic episodes and pain score, analgesic requirements, and adverse drug effects were noted in both groups. Statistical analyses were performed by using Student t-test and chi-square test.

RESULTS

Altogether 85 patients, 41 in group A and 44 in group B, were enrolled in the study. The patients' average age was 31.72±12.63 years, and the male-to-female ratio was 1.5:1. Demographic profiles, stone size, and baseline investigations were comparable between the 2 groups. The stone expulsion rate was significantly higher in the tadalafil group than in the tamsulosin group (84.1% vs. 61.0%, p=0.017). Although the occurrence of side effects was higher with tadalafil, this difference was not significant (p=0.099). There were no serious adverse effects.

CONCLUSIONS

Tadalafil has a significantly higher stone expulsion rate than tamsulosin when used as a medical expulsive therapy for distal ureteral stones sized 5-10 mm. Both drugs are safe, effective, and well tolerated with minor side effects.

Comparative efficacy of tadalafil versus tamsulosin as the medical expulsive therapy in lower ureteric stone: a prospective randomized trial

Introduction

In recent years, medical expulsive therapy has been used in the management of distal ureteric stones as a supplement to conservative treatment. Therefore, we conducted a prospective randomized study to evaluate the possible role of tadalafil individually in comparison with proven tamsulosin therapy in ureteric stone expulsion.

The aim of this study is to compare the safety and efficacy of a phosphodiesterase-5 inhibitor (tadalafil) and an α-1 blocker (tamsulosin) as medical expulsive therapy for distal ureteric calculi.

Material and methods

Between August 2014 and October 2015, 207 patients who presented with distal ureteric stones of size 5–10 mm were randomly divided into two groups: tadalafil (Group A) and tamsulosin (Group B). Therapy was given for a maximum of 4 weeks. Stone expulsion rate, time to stone expulsion, analgesic use, number of hospital visits for pain, follow-up, endoscopic treatment and adverse effects of drugs were noted. Both groups were compared for normally distributed data by percentage, analysis of variance, and T-test. All the classified and categorical data were analyzed for both groups using the chi-square test.

Results

A statistically significant expulsion rate of 84.0% in Group A compared with 68.0% in Group B (P value = 0.0130), and shorter stone expulsion time in Group A (14.7±3.8) in comparison to Group B (16.8 ±4.5) was observed. Statistically significant differences were noted in renal colic episodes and analgesic requirement in Group A than Group B. No serious adverse effects were noted.

Conclusions

Tadalafil is safe, efficacious, and well tolerated as medical expulsive therapy for distal ureteric stones. This study showed that tadalafil increases ureteric stone expulsion quite significantly along with better control of pain and significantly lower analgesic requirement.

The Role of Nitric Oxide and Hydrogen Sulfide in Urinary Tract Function

This MiniReview focuses on the role played by nitric oxide (NO) and hydrogen sulfide (H₂ S) in physiology of the upper and lower urinary tract. NO and H₂ S, together with carbon monoxide, belong to the group of gaseous autocrine/paracrine messengers or gasotransmitters, which are employed for intra- and intercellular communication in almost all organ systems. Because they are lipid-soluble gases, gaseous transmitters are not constrained by cellular membranes, so that their storage in vesicles for later release is not possible. Gasotransmitter signals are terminated by falling concentrations upon reduction in production that are caused by reacting with cellular components (essentially reactive oxygen species and NO), binding to cellular components or diffusing away. NO and, more recently, H₂ S have been identified as key mediators in neurotransmission of the urinary tract, involved in the regulation of ureteral smooth muscle activity and urinary flow ureteral resistance, as well as by playing a crucial role in the smooth muscle relaxation of bladder outlet region. Urinary bladder function is also dependent on integration of inhibitory mediators, such as NO, released from the urothelium. In the bladder base and distal ureter, the co-localization of neuronal NO synthase with substance P and calcitonin gene-related peptide in sensory nerves as well as the existence of a high nicotinamide adenine dinucleotide phosphate-diaphorase activity in dorsal root ganglion neurons also suggests the involvement of NO as a sensory neurotransmitter.

Sildenafil citrate as a medical expulsive therapy for distal ureteric stones: A randomised double-blind placebo-controlled study

Objective

To study the effect of sildenafil citrate on spontaneous passage of distal ureteric stones (DUS).

Patients and methods

This was a randomised double-blinded placebo-controlled study of 100 patients with DUS. Inclusion criteria were: male, age 18–65 years, normal renal function, and a single radiopaque unilateral DUS of 5–10 mm. Patients were randomly allocated into two equal groups, one that received placebo and the other that received 50 mg sildenafil citrate once daily. Both investigators and patients were masked to the type of treatment. Patients self-administered the medication until spontaneous passage of the DUS. In patients where there was uncontrolled pain, fever, an increase in serum creatinine of >1.8 mg/dL, progressive hydronephrosis or no further progress after 4 weeks, a decision was taken for further treatment.

Results

In all, 47 and 49 patients were available for analysis in both the placebo and sildenafil citrate groups; respectively. Both groups were comparable for age and stone characteristics. Spontaneous expulsion occurred in 19 of 47 patients (40.4%) in the placebo group and in 33 of 49 (67.3%) in the sildenafil citrate group (P = 0.014). The mean time to stone expulsion was significantly shorter in the sildenafil citrate group (P < 0.001). A multivariable Cox proportional hazards model showed that receiving sildenafil citrate was the only independent factor that had a significant impact on stone passage with a hazard ratio of 2.7 (95% confidence interval 1.5–4.8; P < 0.001).

Conclusion

Sildenafil citrate enhances spontaneous passage of 5–10 mm DUS.

Effects of PDE5 Inhibitors and sGC Stimulators in a Rat Model of Artificial Ureteral Calculosis

Urinary colics from calculosis are frequent and intense forms of pain whose current pharmacological treatment remains unsatisfactory. New and more effective drugs are needed to control symptoms and improve stone expulsion. Recent evidence suggested that the Nitric Oxide (NO) / cyclic guanosine monophosphate (cGMP) / phosphodiesterase type 5 (PDE5) system may contribute to ureteral motility influencing stone expulsion. We investigated if PDE5 inhibitors and sGC stimulators influence ureteral contractility, pain behaviour and stone expulsion in a rat model of ureteral calculosis. We investigated: a)the sex-specific PDE5 distribution in the rat ureter; b)the functional in vitro effects of vardenafil and sildenafil (PDE5 inhibitors) and BAY41-2272 (sGC stimulator) on induced ureteral contractility in rats and c)the in vivo effectiveness of vardenafil and BAY41-2272, alone and combined with ketoprofen, vs hyoscine-N-butylbromide alone or combined with ketoprofen, on behavioural pain indicators and stone expulsion in rats with artificial calculosis in one ureter. PDE5 was abundantly expressed in male and female rats’ ureter. In vitro, both vardenafil and BAY41-2272 significantly relaxed pre-contracted ureteral strips. In vivo, all compounds significantly reduced number and global duration of “ureteral crises” and post-stone lumbar muscle hyperalgesia in calculosis rats. The highest level of reduction of the pain behaviour was observed with BAY41-2272 among all spasmolytics administered alone, and with the combination of ketoprofen with BAY41-2272. The percentage of stone expulsion was maximal in the ketoprofen+BAY41-2272 group. The NO/cGMP/PDE5 pathway is involved in the regulation of ureteral contractility and pain behaviour in urinary calculosis. PDE5 inhibitors and sGC stimulators could become a potent new option for treatment of urinary colic pain.

Does this case hold the answer to one of the worse types of pain in medicine--that of loin pain haematuria syndrome (LPHS)

A patient with loin pain haematuria syndrome suffering chronic throbbing pulsing pain overlaid with prolonged periods of incapacitating colic and overnight vomiting was presented 10 months following diagnosis. Ultrasound was normal. No renal or ureteral stones, or filling defects were seen on CT. At cytoscopy, bladder and urethra were normal, and bloody urine effluxed from the left ureteric orifice. The ureters were normal at diagnosis, and developed new abutting non-penetrating calcifications by 8 months. Pain episodes of complete incapacitating intensity of 2-4 h duration were reduced to 10 min with 5 mg crushed tadalafil administered at onset. If tadalafil was delayed to after onset, the original course of agony resulted. Daily tadalafil reduced loin pain intensity, but not the exacerbations. Tadalafil efficacy may indicate that the pain exacerbations are due to spasm of ureter smooth muscle. 5 mg tadalafil taken at onset alleviated severe loin pain exacerbations in this case of loin pain haematuria syndrome.

An evaluation of vardenafil as a calcium channel blocker in pulmonary artery in rats

OBJECTIVE

Vardenafil was reported to relax rat pulmonary artery through endothelium-dependent mechanisms. The aim of this in vitro study was to investigate other related mechanisms for this effect.

MATERIALS AND METHODS

Endothelium-intact and denuded artery rings were suspended in order to record isometric tension. In the rings with or without endothelium, the concentration-response curves for vardenafil were generated. In the rings without endothelium the contractile response induced by phenylephrine (Phe) or KCl was assessed in the presence or absence of vardenafil. In the last set of experiments, pulmonary artery rings were exposed to calcium-free isotonic depolarizing solution and the contractile response induced by the addition of calcium was evaluated in the presence or absence of vardenafil, nifedipine, verapamil or 1H-[1,2,4] oxadiazolo[4,3-a] quinoxalin-1-one (ODQ).

RESULTS

Vardenafil attenuated pulmonary artery contraction induced by phenylephrine in the presence and absence of endothelium. In addition, vardenafil attenuated both Phe or KCl-induced contraction but, it's effect on the KCl dose-response curve was more significant. Vardenafil also inhibited the contractile response induced by calcium in a dose-dependent manner. Addition of nifedipine or verapamil did not significantly alter this effect while ODQ incubation significantly inhibited vardenafil-induced relaxation.

CONCLUSION

From these findings, it was proposed that vardenafil relaxed rat pulmonary artery through inhibiting calcium influx.

In vitro Evaluation of Ureteral Contractility: A Comparative Assessment of Human, Porcine and Sheep Ureteral Response to Vardenafil

Objectives: Basic science studies of ureteral physiology and pathophysiology are commonly performed on animal ureters due to several limitations associated with human ureteral sampling. In this work we question whether animal ureters are good replicas of human ureteral behavior for pharmacological studies. Materials and Methods: Ureteral rings from human, porcine and ovine ureters underwent the same organ bath protocol. After stimulation with KCl, ureters were subjected to different doses of vardenafil. Basic contractility and ureteral response to vardenafil were analyzed. Results: A different pattern of basic contractility was evidenced between species. Vardenafil administration induced a dose-dependent reduction in KCl-induced amplitude increase in human ureters and a dose-dependent reduction in autonomic contractile rhythm of porcine and ovine ureters. Although animal ureters could predict the relaxant response of human samples to vardenafil, its effect would have been overestimated using only animal models. Conclusions: Human ureteral investigations cannot entirely be replaced by existing animal models since results of the latter will vary significantly according to the tested pharmaceutical agent.

Comparative efficacy of tamsulosin versus tamsulosin with tadalafil in combination with prednisolone for the medical expulsive therapy of lower ureteric stones: a randomized trial

PURPOSE

To compare the safety and efficacy of tamsulosin and tamsulosin with the phosphodiesterase-5 inhibitor tadalafil in combination with prednisolone as medical expulsive therapies for lower ureteric stones.

MATERIALS AND METHODS

Between July 2011 and December 2012, 62 adult patients presenting with distal ureteric stones sized 5 to 10 mm were randomized equally to treatment with tamsulosin (group A) or tamsulosin with tadalafil (group B). Therapy was given for a maximum of 6 weeks. In addition, patients in groups A and B were given 5-mg prednisolone once daily (maximum 1 week). The stone expulsion rate, time to stone expulsion, analgesic use, number of hospital visits for pain, follow-up and endoscopic treatment, and adverse effects of the drugs were noted. Statistical analyses were done by using Student t-test and chi-square test.

RESULTS

There was a higher expulsion rate (83.9% in group B and 74.2% in group A) and a lower time to expulsion in both treatment groups than in historical controls used in earlier studies. However, these results were not statistically significant (p=0.349, p=0.074, respectively). Statistically significant differences were noted in hospitalization for colic and analgesic requirement, which were less in group B than in group A. There were no serious adverse events. Another important finding was improvement in erectile function in group B.

CONCLUSIONS

Medical expulsive therapy for distal ureteric stones using tamsulosin and tadalafil with prednisolone is safe and efficacious. Also, the prescription of tadalafil in cases of erectile dysfunction with the development of lower ureteric stones may provide additional advantages.

Hyoscine N-butylbromide (Buscopan®) in the treatment of acute ureteral colic: what is the evidence?

OBJECTIVE

To investigate the evidence for the use of hyoscine N-butylbromide (HBB) in the treatment of acute renal colic.

METHODS

A literature search was performed using the keywords 'hyoscine N-butylbromide', 'ureteral colic', 'spasmolytic', 'anticholinergic' and 'analgesia'. The articles were given the appropriate level of evidence according to the Oxford Centre for Evidence-Based Medicine Levels of Evidence guidelines.

RESULTS

The analgesic effect of HBB as monotherapy is inferior to that of opioids and/or non-steroidal anti-inflammatory drugs (NSAIDs). It does provide an analgesic and antispasmodic effect, but not as long-lasting as NSAIDs. HBB does not serve as an adjunct to opioids. Furthermore, it does not facilitate passage of ureteral stones and has no effect on expulsion rate.

CONCLUSIONS

HBB is often used where urinary tract smooth muscle spasm is thought to be part of the pathophysiological process. According to the evidence, administration of HBB follows non-peer-reviewed protocols which are based on empiric recommendations. Its role is still unclear, as it appears to have no advantage when used as monotherapy over established forms of analgesia. There appears to be a time-dependent relation to pain reduction following parenteral administration, but this needs to be confirmed by more prospective randomized cohorts.

Vardenafil ameliorates immunologic- and non-immunologic-induced allergic reactions

Cyclic nucleotides, such as cAMP and cGMP, play a protective role in the modulation of the activity of some inflammatory cells in allergic disorders. Their intracellular concentrations are tightly regulated by the phosphodiesterases (PDEs). The protective efficacy of the selective PDE5 inhibitor vardenafil against mast-cell-mediated allergic reactions in murine models has been investigated. Compound 48/80 was used as a direct mast cell degranulator to induce anaphylaxis. Vardenafil (administered orally at 5, 10, 20, 40, and 80 mg/kg body mass) significantly (P < 0.05, n = 12) increased protection against compound-48/80-induced anaphylaxis in mice to 33.33%, 66.67%, 66.67%, 83.33%, and 66.67% respectively compared with the control (vehicle). In passive cutaneous anaphylaxis (PCA) in rats, vardenafil (10 mg/kg body mass) significantly (P < 0.05, n = 6) decreased Evans' blue dye extravasation (4.6-fold). Pre-incubation of isolated rat peritoneal mast cells (RPMCs) with vardenafil (10 and 100 μmol/L) significantly (P < 0.05, n = 6) reduced compound-48/80-induced histamine release by 2.8- and 3-fold, respectively. Moreover, histamine release by immunogenic stimulation of sensitized RPMCs by egg albumin significantly declined following pre-incubation with vardenafil (10 and 100 μmol/L) by 1.94- and 1.99-fold, respectively. In conclusion, inhibition of PDE5 by vardenafil ameliorated immunologic and non-immunologic mast-cell-mediated allergic reactions and reduced histamine release, providing evidence for the potential anti-allergic properties of vardenafil.

Effect of tadalafil in chronic renal failure rabbits: relevance to erectile dysfunction

It is of great importance to investigate an effective and reliable medication against chronic renal failure (CRF)-related erectile dysfunction (ED), which aims to improve patients' life qualities. The concentrations of cyclic guanosine monophosphate (cGMP) in the corpus cavernosal smooth muscle of both CRF and control rabbits were measured. The effects of various concentrations of tadalafil, papaverine, and sodium nitroprusside on the relaxation responses of corpus cavernosal smooth muscle pre-contracted with phenylephrine in CRF rabbits were observed. There was significant difference in the concentration of cGMP between CRF and control rabbits (P<0.01). Tadalafil had the greatest impacts on CRF rabbits when given the same concentration of papaverine or sodium nitroprusside and particularly significant differences were identified under the concentration levels of 10⁻⁵ and 10⁻⁴ mol/L (P<0.01). The results suggest that the cGMP concentrations of the corpus cavernosum had been greatly reduced in CRF rabbits compared with control rabbits and that tadalafil may be an ideal medication for use in the treatment of CRF-related ED.

Mammalian Cyclic Nucleotide Phosphodiesterases: Molecular Mechanisms and Physiological Functions

The superfamily of cyclic nucleotide (cN) phosphodiesterases (PDEs) is comprised of 11 families of enzymes. PDEs break down cAMP and/or cGMP and are major determinants of cellular cN levels and, consequently, the actions of cN-signaling pathways. PDEs exhibit a range of catalytic efficiencies for breakdown of cAMP and/or cGMP and are regulated by myriad processes including phosphorylation, cN binding to allosteric GAF domains, changes in expression levels, interaction with regulatory or anchoring proteins, and reversible translocation among subcellular compartments. Selective PDE inhibitors are currently in clinical use for treatment of erectile dysfunction, pulmonary hypertension, intermittent claudication, and chronic pulmonary obstructive disease; many new inhibitors are being developed for treatment of these and other maladies. Recently reported x-ray crystallographic structures have defined features that provide for specificity for cAMP or cGMP in PDE catalytic sites or their GAF domains, as well as mechanisms involved in catalysis, oligomerization, autoinhibition, and interactions with inhibitors. In addition, major advances have been made in understanding the physiological impact and the biochemical basis for selective localization and/or recruitment of specific PDE isoenzymes to particular subcellular compartments. The many recent advances in understanding PDE structures, functions, and physiological actions are discussed in this review.

Cyclic nucleotide metabolism including nitric oxide and phosphodiesterase-related targets in the lower urinary tract

The clinical data on the use of the orally active phosphodiesterase (PDE) type 5 inhibitors sildenafil (VIAGRA™), vardenafil (LEVITRA™), and tadalafil (CIALIS™) for the treatment of male erectile dysfunction have boosted research activities on the physiology and pharmacology of the organs of the lower urinary tract (LUT). This includes both intracellular signal transduction in the prostate, urinary bladder (detrusor), and urethra, as well as central brain and spinal cord pathways controlling the function of the LUT. Such efforts provided the basis for the development of new therapeutic modalities into the management of dysfunctions/ syndromes of the LUT, some of which are already offered to the patients. The pharmacological treatment of the overactive bladder and the so-called benign prostatic syndrome, including LUT symptomatology and bladder outlet obstruction secondary to benign prostatic enlargement, has primarily focused on selective, orally available drugs acting by influencing intracellular regulatory mechanisms. These agents are regarded efficacious, have a fast onset of drug action in the target tissue and an improved effect-to-side-effect ratio. Better understanding of the functional significance of proteins related to cyclic nucleotide-dependent pathways, such as nitric oxide synthase, cytosolic and membrane-bound guanylyl cyclases, PDE isoenzymes and cyclic AMP- and cyclic GMP-binding protein kinases, the relative distribution in tissues of the LUT, and the consequences for urogenital function, seems to be of particular interest in order to identify new or more selective pharmacological approaches to manage disorders of the LUT. The present review focuses on cyclic nucleotide-related targets involved in the control of the function of the bladder, prostate, and urethra and the significance of those proteins in the process of evolving new pharmacological options for the treatment of LUT symptoms secondary to benign prostatic hyperplasia as well as dysfunctions of the storage and voiding capability of the urinary bladder.

Treatment of erectile dysfunction and lower urinary tract symptoms by phosphodiesterase inhibitors

To date, it is widely accepted that several disorders of the male and female urogenital tract, such as erectile dysfunction, bladder overactivity, urinary stone disease, the benign prostatic syndrome, as well as symptoms of female sexual arousal and orgasmic dysfunctions, can be therapeutically approached by influencing the function of the smooth musculature of the respective organs. To achieve a pronounced drug effect without significant adverse events, a certain degree of tissue selectivity is mandatory. Selective intervention in intracellular pathways regulating smooth muscle tone has become the most promising strategy to modulate tissue and organ function. Since the concept of taking a pill to relieve symptoms of lower urinary tract dysfunction is now widely accepted following the successes of phosphodiesterase 5 (PDE5) inhibitor treatment of erectile dysfunction, the treatment of urological diseases has focused on orally available drugs acting via influencing intracellular signaling pathways, thereby combining a high response rate with the advantage of an on-demand intake. Specifically, the use of isoenzyme-selective PDE inhibitors offers great opportunities in the medical treatment of various genitourinary diseases. These agents are regarded to be safe and to be efficacious, i.e., having a fast onset of drug action and an improved effect-to-side-effect ratio. As experience with this class of compounds and their use in urology is rapidly growing, basic and clinical research in this field will most likely expand the pharmacological armamentarium of innovative treatment options in the next few years. The purpose of this review is to summarize current, as well as potential, upcoming indications for the use of PDE inhibitors in the pharmacotherapy of male erectile dysfunction and lower urinary tract symptoms.

cGMP-dependent protein kinases and cGMP phosphodiesterases in nitric oxide and cGMP action

To date, studies suggest that biological signaling by nitric oxide (NO) is primarily mediated by cGMP, which is synthesized by NO-activated guanylyl cyclases and broken down by cyclic nucleotide phosphodiesterases (PDEs). Effects of cGMP occur through three main groups of cellular targets: cGMP-dependent protein kinases (PKGs), cGMP-gated cation channels, and PDEs. cGMP binding activates PKG, which phosphorylates serines and threonines on many cellular proteins, frequently resulting in changes in activity or function, subcellular localization, or regulatory features. The proteins that are so modified by PKG commonly regulate calcium homeostasis, calcium sensitivity of cellular proteins, platelet activation and adhesion, smooth muscle contraction, cardiac function, gene expression, feedback of the NO-signaling pathway, and other processes. Current therapies that have successfully targeted the NO-signaling pathway include nitrovasodilators (nitroglycerin), PDE5 inhibitors [sildenafil (Viagra and Revatio), vardenafil (Levitra), and tadalafil (Cialis and Adcirca)] for treatment of a number of vascular diseases including angina pectoris, erectile dysfunction, and pulmonary hypertension; the PDE3 inhibitors [cilostazol (Pletal) and milrinone (Primacor)] are used for treatment of intermittent claudication and acute heart failure, respectively. Potential for use of these medications in the treatment of other maladies continues to emerge.

Ureteral motility

The pyeloureteral function is to transport urine from the kidneys into the ureter toward the urinary bladder for storage until micturition. A set of mechanisms collaborates to achieve this purpose: the basic process regulating ureteral peristalsis is myogenic, initiated by active pacemaker cells located in the renal pelvis. Great emphasis has been given to hydrodynamic factors, such as urine flow rate in determining the size and pattern of urine boluses which, in turn, affect the mechanical aspects of peristaltic rhythm, rate, amplitude, and baseline pressure. Neurogenic contribution is thought to be limited to play a modulatory role in ureteral peristalsis. The myogenic theory of ureteral peristalsis can be traced back to Engelmann (1) who was able to localize the peristaltic pressure wave's origin in the renal pelvis and suggested that the ureteral contraction impulse passes from one ureteral cell to another, the whole ureter working as a functional syncitium. Recent studies of ureteral biomechanics, smooth muscle cell electrophysiology, membrane ionic currents, cytoskeletal components and pharmacophysiology much improved our understanding of the mechanism of how the urine bolus is propelled, how this process is disturbed in pathological states, and what could be done to improve it.

Erectile dysfunction and lower urinary tract

During the last decades it turned out that the NO/cGMP signaling cascade is one of the most prominent regulators of a variety of physiological and pathophysiological processes in a broad range of mammalian tissues. Thus cGMP is a key second messenger and targeting this pathway by increasing intracellular cGMP levels is a very successful approach in pharmacology as shown for nitrates, PDE5 inhibitors and more recently for stimulators of the guanylate cyclase. Besides the beneficial effects of cGMP elevation in cardiac, vascular, pulmonary, renal or liver disorders the launch of PDE5 inhibitors for the treatment of erectile dysfunction 10 years ago, has directed a lot of attention to the NO/cGMP signaling in the lower urinary tract. Triggered by the use of PDE5 inhibitors in ED it turned out that cGMP is a common regulatory mechanism for lower urinary tract function also beyond ED. In recent years intense research and development efforts were undertaken to elucidate the role of the NO/cGMP and to fully exploit the therapeutic implications of cGMP elevation in urological disorders in ED and beyond. Therefore we have summarized the effects of cGMP elevation for treatment of erectile dysfunction in males and in females. We have also reviewed the recent pre-clinical and clinical lines of evidence for treatment options of benign prostatic hyperplasia and lower urinary tract symptoms in male patients and overactive bladder and urinary incontinence in female patients. In addition we also touch more speculative concepts using cGMP elevating drugs for the treatment of premature ejaculation, peyornies disease and stone disease.

Oral phosphodiesterase type 5 inhibitors: nonerectogenic beneficial uses

INTRODUCTION

Phosphodiesterase type 5 (PDE5) hydrolyses cyclic guanylate monophosphate (cGMP) specifically to 5' GMP. PDE5 inhibitors were a breakthrough medication that addressed a previously unfulfilled medical need. They promoted vascular relaxation in the corpora cavernosa and penile erection during sexual stimulation. Sildenafil, vardenafil, and tadalafil were approved then introduced as effective treatments for male erectile dysfunction. This impact has stimulated academic, clinical, and industrial research.

AIM

To highlight the nonerectogenic beneficial uses of oral PDE5 inhibitors.

METHOD

A systematic review of published studies in this affair based on a Pubmed and medical subject heading databases search of all concerned articles.

MAIN OUTCOME MEASURES

Demonstrated beneficial as well as applicable uses of oral PDE5 inhibitors.

RESULTS

As chemical molecules, these drugs were shown to exert potential nonerectogenic beneficial effects. They showed efficacy as a useful adjunct in the management of pulmonary hypertension. Additional uses were extended to different utilities: essential hypertension, benign prostatic hyperplasia, gastrointestinal disorders, endothelial dysfunction, female sexual dysfunction, genital blood flow, exercise capacity, Raynaud's phenomenon, sperm motility, etc.

CONCLUSION

Exploring PDE5 inhibitors for their possible medical applications in diverse specialties seems to be beneficial in making use of these molecules for the welfare of humanity.