An observational study on the efficacy of mirabegron in medical expulsive therapy of the lower ureteric calculus

Purpose: Medical expulsive therapy (MET) is used in lower ureteric calculus to reduce symptoms, to facilitate passage, and to decrease the requirement of endourological surgical interventions. Alpha-blockers, spasmolytics, and calcium channel blockers have been shown to be effective in clinical trials. Beta-3 receptor stimulation in the ureter has been shown to decrease the intraluminal pressure. Thus, Mirabegron, beta 3 receptor agonist, can be thought as alternative MET agent. Materials and Methods: We have done prospective observational study to see the efficacy of mirabegron for MET of lower ureteric calculus ≤10 mm in size. Patients were divided into two groups: Group A (n = 50) received diclofenac 50 mg twice daily for 5 days then on demand for 4 weeks and Group B (n = 50) received diclofenac 50 mg twice daily for 5 days than on demand and mirabegron 50 mg daily for 4 weeks. Patients were followed up weekly with clinical examination, ultrasound screening of kidney, ureter, and bladder (KUB) and noncontrast computed tomography scan KUB after the 28th day of therapy. Results: We found that the passage of stone is significantly higher in mirabegron group (Group A: 68% and Group B: 92%; P < 0.05), and this effect is also statistically significant for stones <7 mm size (Group A: 73.91%, Group B: 96.96%, P = 0.01026). Duration of stone expulsion in Group A: 20.29 ± 5.512 days and Group B: 10.65 ± 4.294 days (P = 0.00001) and the relief of storage symptoms are earlier in mirabegron group (Group A: 16.28 ± 5.65 days and Group B: 6.2 ± 2.58 days, P = 0.00001). Conclusion: Our study reveals that Mirabegron is effective for the treatment of lower ureteric stones ≤10 mm size, especially for stone of size <7 mm and it improves the storage symptoms in these patients.