CONFLICT OF INTEREST STATEMENT Authors have no relevant disclosures. Supporting Information Filename Description jgs18665-sup-0001-Supinfo.pdfPDF document, 304.3 KB Table S1. STROBE and RECORD checklists. Table S2. Coding definition for outcomes. Table S3. Coding definition for comorbidities. Table S4. Individual drug information for concomitant prescriptions. Table S5. Full baseline characteristics of new baclofen users and tizanidine users. Table S6.