Adding Mirabegron to Solifenacin to Treat Overactive Bladder Has Little Impact on Postvoid Residual Volume or Urinary Retention Risk

Inhibition of prejunctional parasympathetic pathways by β3-adrenoceptor agonists in the isolated pig detrusor: comparison with human detrusor studies

Adrenergic receptors of the β₃-subtype (β₃-ADRs) seem to represent a new target for a more effective pharmacological treatment of overactive bladder (OAB), a wide spread urinary disorder. A promising opportunity for OAB therapy might rely on the development of selective β₃-ADR agonists, but an appropriate preclinical screening, as well as investigation of their pharmacological mechanism(s), is limited by poor availability of human bladder samples and of translational animal models. In this study, we used the porcine urinary bladder as experimental tool to ascertain the functions of β₃-ADRs in the control the parasympathetic motor drive. Tritiated acetylcholine ([³H]-ACh), mainly originated from neural stores, was released by electrical field stimulation (EFS) in epithelium-deprived detrusor strips from pigs bred without estrogens. EFS produced simultaneously [³H]-ACh release and smooth muscle contraction allowing to asses neural (pre-junctional) and myogenic (postjunctional) effects in the same experiment. Isoprenaline and mirabegron produced on the EFS-evoked effects a concentration-dependent inhibition antagonized by L-748,337, a high selective β₃-ADR antagonist. The analysis of the resultant pharmacodynamic parameters supports the notion that in pig detrusors, as well as in previously described human detrusors, the activation of inhibitory β₃-ADRs can modulate neural parasympathetic pathways. In such inhibitory control, the involvement of membrane K⁺ channels, mainly of the SK type, seems to play a pivotal role similarly to what previously described in humans. Therefore, the isolated porcine detrusor can provide a suitable experimental tool to study the mechanisms underlying the clinical efficacy of selective β₃-ADR compounds for human use.

Oral anticholinergic drugs versus placebo or no treatment for managing overactive bladder syndrome in adults

BACKGROUND

Around 16% of adults have symptoms of overactive bladder (OAB; urgency with frequency and/or urge incontinence), with prevalence increasing with age. Anticholinergic drugs are commonly used to treat this condition. This is an update of a Cochrane Review first published in 2002 and last updated in 2006.

OBJECTIVES

To assess the effects of anticholinergic drugs compared with placebo or no treatment for treating overactive bladder syndrome in adults.

SEARCH METHODS

We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP and handsearching of journals and conference proceedings (searched 14 January 2020), and the reference lists of relevant articles. We updated this search on 3 May 2022, but these results have not yet been fully incorporated.

SELECTION CRITERIA

We included randomised or quasi-randomised trials in adults with overactive bladder syndrome that compared an anticholinergic drug alone with placebo treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and extracted data from the included studies, including an assessment of the risk of bias. We assessed the certainty of the body of evidence using the GRADE approach. We processed data as described in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 104 studies, 71 of which were new or updated for this version of the review. Although 12 studies did not report the number of participants, there were 47,106 people in the remainder of the included studies. The majority of the studies had insufficient information to allow judgement of risk of bias and we judged them to be unclear for all domains. Nine anticholinergic drugs were included in these studies: darifenacin; fesoterodine; imidafenacin; oxybutynin; propantheline; propiverine; solifenacin; tolterodine and trospium. No studies were found that compared anticholinergic drugs to no treatment. At the end of the treatment period, anticholinergics may slightly increase condition-specific quality of life (mean difference (MD) 4.41 lower, 95% confidence interval (CI) 5.28 lower to 3.54 lower (scale range -100 to 0); 12 studies, 6804 participants; low-certainty evidence). Anticholinergics are probably better than placebo in terms of patient perception of cure or improvement (risk ratio (RR) 1.38, 95% CI 1.15 to 1.66; 9 studies, 8457 participants; moderate-certainty evidence), and the mean number of urgency episodes per 24-hour period (MD 0.85 lower, 95% CI 1.03 lower to 0.67 lower; 23 studies, 16,875 participants; moderate-certainty evidence). Compared to placebo, anticholinergics may result in an increase in dry mouth adverse events (RR 3.50, 95% CI 3.26 to 3.75; 66 studies, 38,368 participants; low-certainty evidence), and may result in an increased risk of urinary retention (RR 3.52, 95% CI 2.04 to 6.08; 17 studies, 7862 participants; low-certainty evidence). Taking anticholinergics may be more likely to lead to participants withdrawing from the studies due to adverse events (RR 1.37, 95% CI 1.21 to 1.56; 61 studies, 36,943 participants; low-certainty evidence). However, taking anticholinergics probably reduces the mean number of micturitions per 24-hour period compared to placebo (MD 0.85 lower, 95% CI 0.98 lower to 0.73 lower; 30 studies, 19,395 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

The use of anticholinergic drugs by people with overactive bladder syndrome results in important but modest improvements in symptoms compared with placebo treatment. In addition, recent studies suggest that this is generally associated with only modest improvement in quality of life. Adverse effects were higher with all anticholinergics compared with placebo. Withdrawals due to adverse effects were also higher for all anticholinergics except tolterodine. It is not known whether any benefits of anticholinergics are sustained during long-term treatment or after treatment stops.

Efficacy and safety of tamsulosin vs its combination with mirabegron in the management of lower urinary tract non-neurogenic overactive bladder symptoms (OABS) because of Benign Prostatic Enlargement (BPE)-An open label randomised controlled clinical study

PURPOSE

The efficacy and safety of βeta-3 agonists (Mirabegron 50 mg) have been sparingly assessed in the published English literature. We aim to do an efficacy-safety analysis of Mirabegron-Tamsulosin combination therapy vs tamsulosin-placebo monotherapy in a select subset of medication virgin Benign Prostatic Enlargement (BPE) patients with coexisting predominant non-neurogenic overactive bladder symptoms (OABS).

METHODS

After prior written informed consent and IEC, 80 patients of uncomplicated BPE with coexisting non-neurogenic OABS and IPSS of >7 without contraindications to drug therapy were computer randomised/allocated to receive either[50 mg Mirabegron plus Tamsulosin 0.4 mg (Intervention arm-I)]or [Tamsulosin 0.4 mg plus capsule lactobacillus (Comparator arm-II)] once daily for 8 weeks. Efficacy was evaluated using the OABS Score (OABSS), mean change in nocturnal frequency (NF), PVR and IPSS, while safety was assessed by recording treatment emergent adverse events (TEAE). Follow-up visits were performed at second, fourth and eighth week.

RESULTS

Patient data in both groups were generally comparable with the exception of NF and IPSS storage sub score (IPSS-ss). Significant improvements were visualised in the eighth week primary endpoint total OABS sub score (OABSS-ss) in the combination group (P < .001).Similar significant improvements were seen with most secondary parameters such as the mean change in NF, IPSS, IPSS-ss, OABS-ss, voided volume, Qmax, and Quality of life index (QOL) (P < .001). No significant increase in PVR was observed in the Mirabegron arm and no patient developed urinary retention. The TEAE were minor, self-limiting and managed symptomatically without drug discontinuity.

CONCLUSION

Mirabegron can be significantly efficacious and safe in ameliorating non-neurogenic OABS induced by BPE vs placebo by initiating combination therapy from the start as opposed to the usual 'add on therapy' protocol. This combination appeared to be superior in terms of overall safety, minimal side effects, better compliance and tolerability vs Tamsulosin monotherapy in select BPE patients with predominant non-neurogenic OABS.

Combination Pharmacotherapy for Treatment of Overactive Bladder (OAB)

Overactive bladder syndrome (OAB) negatively affects the quality of life of patients and their interactions with society. Treatment of OAB starts with behavioral modification and then pharmacotherapy using monotherapy with either antimuscarinics or β3 agonists. The third-line more invasive approaches are the next treatment option currently recommended. Both antimuscarinic agents and β3 agonists work through a different molecular pathway. This brings up the potential of having an additive effect when using a combination treatment for patients with OAB. Currently, the potential for using combination therapy to treat OAB in patients who had no improvement with a monotherapy approach before we attempt a more invasive approach is being explored. Several studies have shown the benefits of combination therapy which will be an additional option to the tools to treat OAB.