A Double-Blind Cross-over Study Comparing the Analgesic Efficacy of Tramadol with Pentazocine in Patients with Osteoarthritis

Tramadol (50 mg qds) and pentazocine (50 mg tds) were compared in a double-blind cross-over study of 40 patients with painful osteoarthritis of the hip and/or knee confirmed by radiological evidence. The primary efficacy variable was the severity of pain as recorded on the diary cards completed daily by each patient Duration of morning stiffness and its severity and the number of paracetamol tablets consumed were also recorded. Tramadol was more effective than pentazocine when assessed by pain scores recorded by patients on a daily diary card (cohort 1, p = 0.089; cohort 2, p = 0.030). Tramadol was also more effective than pentazocine when compared in terms of morning stiffness (p = 0.034) and paracetamol consumption (p = 0.073). In terms of overall assessment of efficacy, patients rated tramadol more highly than pentazocine (p = 0.003). Spontaneous symptoms were reported by 18/34 (53%) patients who took tramadol and 28/36 (78%) patients who took pentazocine. Ten patients withdrew during the first treatment period (four on tramadol, six on pentazocine), and 11 withdrew during the second treatment period (five on tramadol, six on pentazocine). The majority of withdrawals were due to spontaneous symptoms. On the grounds of both efficacy and fewer spontaneous symptoms, tramadol appeared preferable to pentazocine in the treatment of osteoarthritis and thus would appear a useful alternative to those opioids or opioid-containing drugs currently available.