In many cases of neurogenic bladder patients, bladder compliance is lowered, which is a factor that deteriorates renal function. It is known that deterioration of renal function is accompanied in 50 to 70% of patients with low bladder compliance. For patients with poor bladder compliance, a consensus has not yet been established regarding the treatment method. This is especially true in the case of drug treatment rather than surgical methods. There are limited cases where bladder compliance is improved with anticholinergics, which have been conventionally administered to the patients. According to the existing literature, increase of bladder compliance was observed in some patients with anticholinergics such as tolterodine, propiverine, and oxybutynin. But the bladder compliances were not completely normalized in every patient. Moreover, adverse effects of anticholinergics have been reported in a significant number of the patients.

The objective of this study is to analyze the effect of mirabegron (a beta3-adrenoceptor agonist) on bladder compliance in patients who had no effect on bladder compliance with prior anticholinergics treatment. In this study, low bladder compliance is defined as 20 ml/cmH2O or less.

This study will be conducted as a prospective paired comparison study. In this study, low bladder compliance is defined as 20 ml/cmH2O or less. For patients who had no effect on anticholinergic treatment (at least 1 month of treatment). Mirabegron 50mg/day is administered for 8 weeks; and then, previously administered antimuscarinics were administered again for another 8 weeks. On each visit day (after 8 weeks of mirabegron, and after 8 weeks of anticholinergics), urodynamics test, voiding diary, and patient symptom questionnaire evaluations are going to be performed.

Inclusion Criteria:

1. Patients over 19 years of age
2. Bladder compliance is 20ml/cmH2O or less
3. Patient who has been treated with antimuscarinic for at least 1 month, but has not been effective.
4. Patient who agrees to and signs the informed consent

Exclusion Criteria:

1. Those who have taken clinical drugs with other ingredients (other than this experiment) for the past 60 days or participated in clinical trials using other types of medical devices.
2. Those who have previously undergone bladder augmentation
3. Those who currently have an indwelled catheter for urination
4. Those with abnormal findings in renal function (serum creatinine >2 mg/dL)
5. Those with abnormal liver function (serum AST/ALT >2 times upper limit, GGT >3 times upper limit of normal,total bilirubin >2 times upper limit of normal)
6. Those with a history of bladder cancer before screening
7. Those who were diagnosed with interstitial cystitis
8. Those with active UTI
9. Those who are pregnant or breastfeeding
10. Those with a history of previous treatment with mirabegron
11. Those who are allergic to beta 3 agonist, who are expected to be allergic to mirabegron
12. Those confirmed as resting SBP >180 mmHg and/or DBP >110 mmHg
13. Those confirmed as resting HR >100 beats per minute
14. Male patients who are likely to become pregnant or donate sperm during the study period or within 28 days of the last drug administration of the study.
15. Those who do not respond to surveys and research follow-up visits
16. Those for whom the researcher judges that the treatment method of this study is not the best treatment for the patient