Comparison of Effectiveness and Safety of Tramadol/Acetaminophen and Non-steroidal Anti-inflammatory Drugs (NSAIDs) for Treatment of Knee Osteoarthritis in Elderly Patients

ABSTRACT

OBJECTIVE: To compare the analgesic effectiveness and safety of tramadol 37.5 mg/acetaminophen 325 mg combination tablets (tramadol/acetaminophen) with non-steroidal anti-inflammatory drugs (NSAIDs) for the treatment of osteoarthrits in elderly patients. METHODS: This randomized controlled study enrolled 48 patients with chronic knee osteoarthritis where the diagnostic period was over 3 months. Patients with at least moderate pain [visual analog scale (VAS) with scores > or =40/100 mm] after the washout period were randomized to tramadol/acetaminophen or NSAID. All patients received tramadol/acetaminophen 1 tablet TID or NSAID (naproxen 500 mg) BID. The primary outcome measures were the final pain VAS scores. Secondary measures included pain relief (5 point Likert scale), adverse events, and overall medication assessments. RESULTS: In total, 43 intent-to-treat (ITT) patients received tramadol/acetaminophen (n=21) or NSAID (n=22). Mean baseline pain VAS scores showed no difference between two groups. ITT analysis showed significantly better mean final VAS scores (38.45 vs 31.24, p=0.004) and mean final pain relief scores (2.18 vs 2.95; p=0.007) for tramadol/acetaminophen rather than for NSAID. The most common treatment related adverse events with tramadol/acetaminophen were nausea/vomiting (47.6%) and constipation (33.3%). Epigastric soreness and heartburn was more frequent in NSAID treatment. CONCLUSION: Tramadol/acetaminophen combination showed better effectiveness in pain reduction compared with NSAIDs when used for the treatment of osteoarthritis in elderly patients.