Methocarbamol vs Oxybutynin for Management of Pain and Discomfort S/P Ureteroscopy Procedure

This study is comparing the effectiveness of pain control after ureteroscopy for stone removal between two medications: oral Oxybutynin XL 10mg daily and oral Methocarbamol 750mg every six hours as needed for spasms. The study medications will be given in addition to a standard postoperative pain regiment including Tylenol 1000mg every six hours, Tamsulosin 0.4mg daily, phenazopyridine 200mg every eight hours, and diclofenac 50mg every eight hours, and finally the investigational agent (either oral oxybutynin XL 10mg once daily or oral methocarbamol 750mg every six hours as needed for pain depending on which group the participant is randomly assigned).

Patients who will be undergoing ureteroscopy for stone removal (anyone with upper tract stones, total stone burden < 2 cm) will be identified in clinic and consented to participate in the study. Patients will be randomized to either methocarbamol or oxybutynin in a 1:1 fashion using RedCAP prior to the procedure. Pain regimen after surgery includes: Tylenol 1000mg every six hours, Tamsulosin 0.4 mg daily, phenazopyridine 200mg every eight hours, and diclofenac 50mg every eight hours, and finally the investigational agent (either oral oxybutynin XL 10 mg once daily or oral methocarbamol 750mg every six hours as needed for pain). Both drugs are FDA approved, but will be used off-label for the purposes of this study. Although oxybutynin is not FDA approved for the treatment of ureteral spasms, multiple studies have been performed to study its efficacy for this indication and it will be used in an off-label fashion. The study will document age, sex, BMI, preoperative stone burden, laterality of surgery, OR duration, laser energy (kJ), laser settings, ureteral access sheath use, stent size, stent duration, stone analysis, preoperative urine culture, stone culture, and any medical comorbidities. Neither patients nor investigators will be blinded to which drug they are receiving.

Patients will be administered the PROMIS questionnaire, which has been validated for assessing ureteral stent symptoms. The VAS pain scale will also be administered to assess pain (scores from 1-10). The PROMIS questionnaire and VAS pain scale will be administered at time of study enrollment or prior to surgery. The questionnaire and VAS pain scale will be administered daily by text message (RedCAP electronic survey) from POD1 until the day of stent removal, and 1 day after the stent is removed. Stent removal typically occurs 3-7 days after surgery. The questionnaires will be completed by the patient on a mobile device. Patients will be asked to complete a drug diary, so study investigators can ensure they took the medication as prescribed. On the final survey (the one sent 1day after stent removal), the study investigators will also inquire about if the patient had any unplanned clinic or ED visits during the period the stent was in.

Inclusion criteria

• Men and women between age 18-80 years who are diagnosed with stones who undergo ureteroscopy and ureteral stent placement.
• Patients who consent to the procedure will be randomized in 1:1 fashion by RedCAP either to the methocarbamol or oxybutynin arm. All patients will receive standard of care diclofenac, tamsulosin, and pyridium for pain control plus one of the study drugs.
• Willing to take only diclofenac (or tramadol for patients with contraindication to diclofenac), phenazopyridine, and acetaminophen for post stent placement discomfort.
• Willing to sign the Informed Consent Form.
• Able to read, understand, and complete patient questionnaires, pain texts, and medication diary.

Exclusion criteria

• Active, symptomatic urinary tract infection.
• Non-stone related ureteral obstruction or stricture.
• Procedural trauma or significant retained stone burden that could significantly contribute to patient discomfort.
• Spinal cord injuries (sensory loss due to injury).
• Non-stone related voiding dysfunction requiring supplemental bladder drainage tubes for more than 24 hours post operatively.
• Chronic opioid usage for pain.
• Members of vulnerable patient populations.