• ABSTRACT
    • This placebo-controlled study examined the analgesic efficacy, safety, and clinical benefit of Tramadol Contramid OAD, a once-daily formulation with both immediate- and extended-release components. Five hundred and fifty-two patients with moderate to severe pain due to osteoarthritis (OA) of the knee were randomized into this multicenter, double-blind, parallel arm study. After randomization to Tramadol Contramid OAD 100, 200, or 300 mg, or to placebo, patients' dose was titrated to the fixed randomized dose and maintained for 12 weeks. Efficacy was evaluated with the Patients' Global Rating of Pain Relief (median ratings at maintenance visits), and the Western Ontario and McMaster University (WOMAC) Pain and Physical Function subscales (percent difference, baseline to end of study) as coprimary endpoints. A responder analysis was conducted (percentage of patients who achieved a 30 percent improvement on their baseline WOMAC pain score). The difference from placebo on the median Patient Global Rating of Pain Relief at the four maintenance visits was statistically significant (200 and 300 mg: p < or = 0.001). Treatment was rated effective or very effective by 75 percent and 80 percent of patients randomized to Tramadol Contramid OAD 200 mg and 300 mg, respectively. There was a 46 percent (300-mg dose; p = 0.016) and 43 percent (200-mg dose; p = 0.05) improvement on the WOMAC pain score (baseline to the end of the study) with Tramadol Contramid OAD compared with 32percent for placebo. The responder analysis demonstrated a statistically significant difference in the percentage of patients who achieved a 30 percent improvement in their baseline WOMAC pain score for both Tramadol Contramid OAD 200 mg (65 percent; p = 0.0095) and 300 mg (65 percent; p = 0.0104) compared with placebo (50 percent). The type and incidence of adverse events were typical of tramadol (nausea, dizziness/vertigo, vomiting, somnolence, and constipation) and the intensity was mild to moderate in 87percent of patients who experienced them regardless of dose. This study shows the efficacy and safety of Tramadol Contramid OAD 200 mg and 300 mg in patients with moderate or severe pain of the knee due to OA.