CARES-Spine (Comprehensive Analgesic, Recovery, and Education Support for Spine Surgery) Trial

Inclusion Criteria: Adults aged 18-64 scheduled for elective spine surgery for lumbar or cervical degenerative disease (e.g. lumbar or cervical disc herniation, lumbar or cervical spinal stenosis, lumbar or cervical degenerative spondylolisthesis, lumbar or cervical disc degeneration, or degenerative cervical myelopathy including cervical spondylotic myelopathy). Preoperative long-term opioid use (Defined as ≥ 90-day duration of use in the 4 months preceding surgery either via self-report or state PDMP. Participants must report at least one of the following on preoperative assessments: Current Opioid Misuse Measure (COMM) score greater than or equal to 9 Answering "Yes" to any of the following items on the modified Brief Pain Inventory (BPI)1) Over the past 24 hours have you needed to take your pain medication to help you sleep; 2)Have you taken any pain medications for any reason other than your pain, such as to reduce anxiety or improve mood? 3) Have you taken more pain medication than was prescribed to you in the past 24 hours? Score of greater than or equal to 2 on any Tobacco, Alcohol, Prescription medication, and other Substance use (TAPS-1) item Positive Alcohol Use Disorders Identification Test (AUDIT-C) score (greater than or equal to 4 for men, greater than or equal to 3 for women) Elevated opioid use 14 days after surgery compared to baseline daily OME Defined as average daily OME assessed over 3 days 1 week before surgery compared to average daily OME reported on postoperative days 12 to 14 to account for as-needed dosing and day-to-day variations in opioid use. English-speaking Ability and willingness to complete online assessments Exclusion Criteria: Infection, tumor, or fracture at the operative site Allergy or intolerance to tizanidine Current use of tizanidine Renal impairment Hepatic impairment including cirrhosis or elevated 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 Cancer diagnosis, active malignant neoplasm (metastatic or local) or evidence of paraneoplastic syndrome Conditions causing inability to complete assessments (education, cognitive ability, mental status, medical status) Participating in another clinical trial with an active treatment arm