Introduction: Knee osteoarthritis (OA) is a common form of arthritis in elders which can lead to reduced daily activity and quality of life. It is important to administer a proper treatment with high efficacy and low side effects. In this study, we evaluated the efficacy of duloxetine and gabapentin in patients with moderate to severe knee OA.
Method: In this randomized clinical trial, 150 patients with moderate to severe knee OA were randomly allocated to receive duloxetine 30 mg (n = 50), gabapentin 300 mg (n = 50), or acetaminophen 1000 mg (n = 50) all twice a day for 12 weeks. Pain severity using visual analogue scale (VAS) and functional status using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were measured before, 2 weeks, 1 month, and 3 months after intervention.
Results: WOMAC total and its subscale score were significantly lower in duloxetine compared to gabapentin in 2 weeks and 1 months after intervention, with no significant difference at the end of the third month. Both gabapentin and duloxetine groups had significantly more reduction in pain VAS and WOMAC and its subscales compared to acetaminophen group, with no significant difference between groups.
Conclusions: Both gabapentin and duloxetine have similar and acceptable effects in pain reduction and improvement of functional status in patients with knee OA at the end of the third month's treatment. Duloxetine effects begin from the first weeks, while gabapentin effects begin gradually with the best at the end of the third month.
Key points: • Medical treatment is used for releiving pain in knee osteoarthritis. • Gabapentin and duloxetine are both effective in reducing pain in knee osteoarthritis.
Keywords: Duloxetine; Gabapentin; Knee osteoarthritis; Pain.