Conversion to Once-Daily Hydromorphone Possible in Opioid-Tolerant Patients With Chronic Low-Back Pain: Presented at AAPM
By Liz Meszaros
NATIONAL HARBOR, Md -- March 28, 2011 -- Opioid-tolerant patients with chronic moderate to severe low-back pain can be converted to a stable dose of once-daily extended release (ER) hydromorphone, according to a study presented here at the 27th Annual Meeting of the American Academy of Pain Medicine (AAPM).
For this open-label dose conversion and titration study, researchers included 447 opioid tolerant patients with chronic, moderate to severe low back pain, as indicated by a mean numeric ratings scale (NRS) score of 6.4, and defined as pain lasting longer than 3 hours per day, on at least 20 days per month.
Patients received once-daily hydromorphone ER (12, 16, 24, 32, 40, 48, or 64 mg). Conversion was achieved using standard morphine conversion tables, and assuming a morphine equivalent:hydromorphone potency ratio of 5:1. For other opioids, an initial dose that was approximately 75% of their previous equianalgesic total daily opioid dose was used for conversion.
Hydromorphone immediate-release rescue medication (2, 4, and 8 mg) was permitted throughout the study. Rescue medication use was unrestricted for the first 3 days, after which dosage was restricted to 2 tablets per day.
Once-daily hydromorphone ER dosing could be adjusted a maximum of twice weekly, and this was based on investigator evaluation of daily pain intensity, use of rescue medications, and tolerability. The most common initial dose of once-daily hydromorphone ER was 12 mg/d (42.5%). During conversion and titration, it was 64 mg/d (21.8%).
In all, 60% of patients (n = 268) achieved an effective dose of once-daily hydromorphone ER. Mean dose of once-daily hydromorphone ER at the end of conversion and titration was 37.8 mg. NRS pain intensity score was reduced by 50% at the end of the conversion and titration phase compared with screening. Mean NRS score was 6.4 at study entry, compared with 2.3 at the end of this phase.
Mean number of rescue medication tablets taken per day was 2.7 during the first 3 days of conversion and titration. Once stable dose was achieved, the mean dose of rescue medication was less than 1 tablet per day.
A total of 55.3% (n = 247) had adverse events during conversion and titration, the majority of were mild to moderate. The most common adverse events were constipation, nausea, somnolence, and headache. Treatment-related adverse events occurred in 43.0% (n = 192) of patients, and the most common of these were constipation (14.3%), nausea (9.6%), somnolence (8.1%), headache (6.0%), and vomiting (4.5%). A total of 13.0% (n = 58) patients discontinued therapy during conversion and titration due to adverse events. Serious events occurring in only 1.3% (n = 6).
“Once-daily hydromorphone ER was well tolerated, with no unexpected safety concerns,” said Donald R. Taylor, MD, Taylor Research, LLC, Marietta, Georgia. “The most common adverse events were consistent with those associated with other potent opioid medications. Further, titration to an effective dose of once-daily hydromorphone ER was accompanied by a reduction in the use of rescue medication for breakthrough pain.”
Funding for this study was provided by Neuromed Pharmaceuticals and Covidien.
[Presentation title: Results of an Open-Label Dose Conversion and Titration Study of Once-Daily Hydromorphone ER in Opioid-Tolerant Patients With Chronic Low Back Pain. Poster 162]