Open-label study to evaluate the efficacy and safety of extended-release hydromorphone in patients with chronic neuropathic pain

OBJECTIVE: To assess the efficacy and safety of once-daily hydromorphone extended-release tablets (OROS [Alza Corporation, Mountain View, CA] hydromorphone ER) in patients with chronic neuropathic pain. DESIGN: Single-center, open-label, 12-week study. PATIENTS: Opioid-tolerant patients with chronic neuropathic pain for $6 months (N = 30). INTERVENTIONS: Patients were converted from previous opioid therapy to OROS hydromorphone ER using a 5:1 morphine:hydromorphone equianalgesic dosing ratio, with an initial 50 percent reduction of the calculated equianalgesic dose, titrated every 3-4 days to adequate analgesia over 2 weeks. OUTCOME MEASURES: The primary efficacy measure was change from baseline to week 12 (end of study) on question #5 ("average pain") of the Brief Pain Inventory (BPI). Secondary measures included least pain, worst pain, current pain, and sleep interference on the BPI, as well as the Pain Quality Assessment Scale (PQAS) and patient global assessment of treatment satisfaction. RESULTS: Thirty patients were enrolled and received $1 dose of OROS hydromorphone ER, titrated to a final mean dose of 26.4 mg/d. Mean (SE) BPI change from baseline to end of study was -1.3 (0.59) for current pain (p < 0.05) and -1.8 (0.61) for worst pain (p < 0.01). Mean (SE) change from baseline was also significant for BPI scores for sleep interference (-1.7 [0.61]; p < 0.01) and PQAS scores (-24.8 [7.9], p < 0.01). The majority (81 percent) of patients were satisfied or very satisfied with treatment. The most common treatment-related adverse events were dizziness, headache, and nausea (two patients each). CONCLUSIONS: Patients with chronic neuropathic pain were safely and effectively converted to and maintained on OROS hydromorphone ER.