Objective: To evaluate the overall safety profile and clinical effectiveness of tramadol hydrochloride/acetaminophen (TA) combination tablets in Japanese patients with chronic noncancer pain unrelieved by non-opioid drugs for up to 12 weeks in real-world practice.
Research design and methods: This survey was a multicenter, prospective, longitudinal registry on the use of TA as a newly initiated pain treatment for chronic noncancer pain incurable by non-opioid analgesics that was conducted under the Good Post Marketing Study Practice regulation controlled by the Japan Ministry of Health, Labor and Welfare. Collected data included socio-demographics, treatment information, incidence of adverse drug reactions (ADRs), numerical rating scale for intensity of pain, EuroQol-5D (EQ-5D) scale, and physician's global impression (PGI) during the 12 week observation period.
Results: A total of 1316 patients were registered. ADRs were reported in 259 patients (20.5%); most events were nonserious (99.4%), including nausea (n = 87 [6.9%]), constipation (n = 63 [5.0%]), dizziness and somnolence (n = 29 [2.3%] each), and vomiting (n = 21 [1.7%]). No event related to drug dependence or respiratory depression was reported. In addition, 82.8% of patients showed acceptable effectiveness based on PGI at Week 4. Numerical rating scale for intensity of pain and EQ-5D utility scores were improved by -2.7 (SD 2.3) and 0.16 (SD 0.20) at Week 4, respectively, and the improvement was maintained until Week 12.
Conclusion: This is a first report to evaluate the risk-benefit profile of TA in Japanese real-world practice using large size registry data. It is suggested that the favorable risk-benefit balance of TA was confirmed for patients with chronic noncancer pain unrelieved by non-opioid drugs in real-world practice. Limitations of this study were those inherent to open-label and non-interventional study designs.
Trial registration: This registry survey is registered at umin.ac.jp (identifier: UMIN000015901).
Keywords: Acetaminophen; Adverse drug reactions; Effectiveness; Naturalistic practice; Pain, Chronic; Tramadol hydrochloride.