BALTIMORE, Md.—A structured plan for tapering opioid therapy results in minimal risk of opioid withdrawal syndrome, concluded a study of patients with chronic, moderate-to-severe pain from osteoarthritis of the hip or knee. These results provide much-needed objective data regarding withdrawal symptoms from opioid treatment, researchers reported at the 29th Annual Scientific Meeting of the American Pain Society.

The 2-week taper procedure used in this study was successful in minimizing the occurrence of opioid withdrawal, concluded Nathaniel Katz, MD, MS, and colleagues. In a 12-week study, 547 patients were titrated over a maximum of 45 days to an effective EMBEDA® dose varying from 20 mg/day to 160 mg/day; 344 patients were subsequently randomized to one of two groups. The first group maintained dose for 12 weeks and the second was force tapered to 0 mg over 2 weeks, then maintained on placebo for 10 weeks.

The Clinical Opiate Withdrawal Scale (COWS) was used to rate withdrawal at randomization and at weeks 1 and 2 of taper. Using the scale, patients rated opioid withdrawal symptom intensity from none (0) to severe (48), as follows: none, 0 to 4; mild, 5 to 12; moderate, 13 to 24; moderately severe, 25 to 36; severe, 37 to 48.

Of 173 patients tapering from EMBEDA to placebo, only 3 (1.7%) had scores indicating moderate withdrawal during week 1 or 2 of the taper period. Two patients had COWS scores of 23 and discontinued due to lack of efficacy. One discontinued during the taper period and one at week 6 of the maintenance period. A third patient with a COWS score of 13 during taper completed the study. Of the 171 patients assigned to maintenance on EMBEDA, none had moderate or greater symptoms of withdrawal during the first 2 weeks of the maintenance period. COWS scores ranged from 0 to 6 (randomization), 0 to 9 (week 1), and 0 to 8 (week 2). Overall mean COWS scores were numerically higher for patients tapered to placebo than for patients maintained on EMBEDA, but all groups had mean scores ≤1.5 at weeks 1 and 2.


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The investigators acknowledged that further study will help determine whether a tapering schedule outside a placebo-controlled trial will produce similar results.