Clinical Research Directory

INCLUSION CRITERIA: * 18 to 75 years of age * Able to speak, write, and read fluently in English * Scheduled for elective surgery at * Stanford University Medical Center, * Brigham and Women's Hospital (Harvard University), * Atrium Health Wake Forest Baptist Medical Center (Wake Forest University), or * University of Kansas Medical Center * Preoperative long-term opioid use (Defined as ≥ 60-day supply of opioids in the 180-day period prior to surgery), identified via self-report, state Prescription Drug Monitoring Program (PDMP), or Electronic Medical Records (EHR). Days may be nonconsecutive, and actual use of opioid supply is not required. * Willing and able to complete online assessments and study calls independently * On the preoperative Baseline assessments, least one of the following: * Current Opioid Misuse Measure (COMM-17): score ≥ 9 * Tobacco, Alcohol, Prescription medication, and other Substance use (TAPS-1): Reported use more frequent than "Never" on any item except Tobacco; for Tobacco, "Yes" to at least one item on the TAPS-2 for Tobacco * Alcohol Use Disorders Identification Test (AUDIT-C): score ≥4 (men), ≥3 (women) * Modified Brief Pain Inventory (mBPI): "Yes" to at least one of the following: * Over the past 24 hours have you needed to take your pain medication to help you sleep? * Have you taken any pain medications for any reason other than your pain, such as to reduce anxiety or improve mood? * Have you taken more pain medication than was prescribed to you in the past 24 hours? * At the Post-Operative Call (7-13 days post-op): Postoperative daily opioid dose ≥ preoperative daily opioid dose (identified during the Pre-Surgery Call 5-1 day before surgery), measured in Morphine Milligram Equivalents (MME). EXCLUSION CRITERIA * Infection, tumor, or fracture at the operative site * Allergy or intolerance to tizanidine * Current use of tizanidine * Renal impairment (Creatinine Clearance \[CrCl\] \< 25 ml/min) * Hepatic impairment, including cirrhosis or elevated liver enzymes * Concurrent use of other α2-adrenergic agonists, skeletal muscle relaxants * Concurrent use of: fluvoxamine, ciprofloxacin,zileuton, fluoroquinolones, antiarrhythmics (amiodarone, mexiletine, propafenone, verapamil), cimetidine, famotidine, oral contraceptive pills, acyclovir, ticlopidine, and fexinidazole * Pre-existing hypotension, sedation, dizziness, severe respiratory insufficiency. * Opioid Use Disorder * Suicidality as assessed by the Patient Health Questionnaire-9 (PHQ-9) Question 9 score ≥ 1 * Pregnancy, breastfeeding, or planning to conceive * Planned cancer treatment in the \< 3 months following surgery * Conditions causing inability to complete assessments (education, cognitive ability, mental status, medical status) * Participating in another clinical trial with an active treatment arm