Double-J ureteral stents are commonly inserted after ureteroscopy, but they may cause bothersome urinary symptoms, pain, sleep disturbance, and reduced quality of life.

This prospective randomized assessor-blinded three-arm clinical trial will compare oral solifenacin, oral melatonin, and their combination for improving ureteral stent-related symptoms in adult patients after unilateral ureteroscopic lithotripsy with insertion of a unilateral Double-J ureteral stent.

Participants will be randomized to receive solifenacin 5 mg once daily, melatonin 3 mg once nightly, or combined solifenacin 5 mg once daily plus melatonin 3 mg once nightly for 14 days after surgery. The primary outcome is the total Ureteral Stent Symptom Questionnaire score at postoperative Day 7. Secondary outcomes include total Ureteral Stent Symptom Questionnaire score at Day 14, change in questionnaire score between Day 7 and Day 14, Insomnia Severity Index score, Visual Analogue Scale pain score, adverse events, treatment compliance, and rescue analgesic consumption.

This is a single-center, prospective, randomized, assessor-blinded, parallel-group, three-arm clinical trial conducted at the Department of Urology, Beni-Suef University Hospital, Egypt.

The study will include adult patients aged 18 to 60 years undergoing unilateral ureteroscopic lithotripsy for ureteral stones with postoperative insertion of a unilateral Double-J ureteral stent. Eligible patients who provide written informed consent will be randomized into one of three treatment groups.

Participants in Group A will receive solifenacin 5 mg once daily. Participants in Group B will receive melatonin 3 mg once nightly. Participants in Group C will receive combined solifenacin 5 mg once daily plus melatonin 3 mg once nightly. Study medication will start immediately after surgery and hospital discharge and will continue for 14 days.

Outcome assessors will remain blinded to treatment allocation throughout the study period. Study assessments will be performed at postoperative Day 7 and postoperative Day 14. Ureteral stent-related symptoms and quality of life will be assessed using the Arabic-validated Ureteral Stent Symptom Questionnaire. Sleep-related symptoms will be assessed using the Arabic version of the Insomnia Severity Index. Pain will be assessed using a Visual Analogue Scale. Drug-related adverse events, treatment compliance, and rescue analgesic consumption will also be recorded during follow-up.

The primary endpoint is the difference among the three study groups in total Ureteral Stent Symptom Questionnaire score at postoperative Day 7.

Inclusion Criteria:

1. Age 18 to 60 years.
2. Patients undergoing unilateral ureteroscopy or ureteroscopic lithotripsy with insertion of a unilateral Double-J ureteral stent.
3. Ability to understand and complete the study questionnaires.
4. Willingness to participate and provide written informed consent.

Exclusion Criteria:

1. Bilateral ureteral stents.
2. Stents inserted for malignant ureteral obstruction or non-stone reconstructive indications.
3. Known hypersensitivity or contraindication to solifenacin or melatonin.
4. History of acute or chronic urinary retention, or evidence of clinically significant bladder outlet obstruction at baseline.
5. History of narrow-angle glaucoma or other contraindications to antimuscarinic therapy, including gastric retention.
6. Significant hepatic impairment.
7. Severe renal impairment if judged clinically relevant to study medication safety.
8. Pre-existing moderate to severe lower urinary tract symptoms unrelated to the stent.
9. Recent use of antimuscarinics, alpha-blockers, or melatonin that may interfere with symptom assessment.
10. Pregnancy or lactation.
11. Inability to complete follow-up.

Individual participant data will not be shared. Only aggregated, de-identified study results will be reported. Individual-level data will remain confidential and will be accessible only to the study investigators and authorized regulatory or ethics committee representatives if required.

Outcome assessors will be blinded to treatment allocation throughout the study period.