Adverse events and continuity of tramadol hydrochloride biphasic immediate–release ⁄ extended–release tablets for patients with chronic pain related to spine diseases

Background: The adverse events (AEs) of tramadol hydrochloride biphasic immediate–release ⁄ extended–release tablet (tramadol IR/ER tablet) in patients with chronic pain related to commonly examined spine diseases have not been extensively studied. Purpose: To clarify the safety and continuity of tramadol IR/ER tablet for chronic pain associated with spine diseases. Methods: This was a retrospective observational study conducted at 9 institutions. We surveyed the records of patients with chronic pain related to spine diseases who were prescribed twice–daily oral tramadol IR/ER tablets. We evaluated AEs associated with tramadol IR/ER tablets and the continuation rate of tramadol IR/ER tablets at 4 weeks. Results: In total, 139 patients met the study criteria. One hundred thirty patients (93.5%) continued to take tramadol IR/ER tablets for 4 weeks. AEs were observed in 39 patients (28.1%) and included constipation in 18 patients (12.9%), nausea in 10 patients (7.2%), somnolence in 8 patients (5.8%), and dizziness in 4 patients (2.9%). Among 41 patients who switched from other tramadol formulations to tramadol IR/ER tablets, the daily dose of tramadol was increased, yet the incidence of AEs was equivalent (9 patients, 22.0%), with no reported occurrences of nausea. Conclusions: The overall incidence of AEs after administration of tramadol IR/ER tablets was 28.1%, and the continuation rate after 4 weeks was 93.5%. For patients with chronic pain related to spine diseases, switching to tramadol IR/ER tablets may allow for safe continuation of pain treatment.