A look at product news from the American Pain Society 2012 Annual Meeting.
Diclofenac Gel Is Safe and Well Tolerated for Long-term Treatment of Knee Osteoarthritis in Older Patients
Researchers evaluated the long-term tolerability of topical diclofenac sodium 1% gel (DSG) in elderly (age 65 years or older) vs. younger (less than 65 years old) patients with a clinical diagnosis of osteoarthritis of the knee with symptom onset of at least six months. Participants had either completed an earlier 12-week study of treatment with DSG or were DSG-naïve. Patients who participated in an earlier study and entered the open-label extension phase were treated with DSG to one or both knees four times a day for 9 months; DSG-naïve patients were treated for 12 months. Patients were allowed to use rescue acetaminophen, were monitored for adverse events, and assessed for pain, stiffness, and physical function using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) every 3 months. A total of 947 patients (575 younger than 65, 372 older than 65) were assessed. Roughly two-thirds of all patients experienced at least one adverse event, with occurrence of the most common adverse events similar for both age groups. Gastrointestinal adverse events were more common in the younger group, whereas application-site dermatitis was more common in the older group. The researchers also reported that all groups had decreased WOMAC pain, stiffness, and physical function scores at 12 months.
High-concentration Topical Capsaicin Formulation Reduces Pain in Patients with Postherpetic Neuralgia
Researchers randomized patients with postherpetic neuralgia to receive either a five-minute application of NGX-1998 liquid highconcentration capsaicin (either 10% or 20%) or placebo and followed them for 12 weeks, assessing the mean percent change from baseline in the “average pain for the past 24 hours” Numeric Pain Rating Scale (NPRS) score during weeks 2-8 (primary endpoint) and weeks 2-12 (secondary). The authors reported that “a clear dose-response was observed in the primary endpoint (-16.7%, -22.3% and -25.1% in the placebo, 10% and 20% treatment groups, respectively) and in the secondary endpoint for Weeks 2-12 ( 16.6%, -22.2% and -26.0% in the placebo, 10% and 20% treatment groups, respectively).” The treatment was well-tolerated, with no patients ending treatment prematurely due to an adverse event. Application site pain and erythema were the most commonly reported adverse events.
Studies Show Butrans Provides Consistent Pain Relief with No End-of-Dose Failure
Researchers analyzed daily pain scores during weeks 2 and 8 of a 12-week trial of Butrans therapy among patients with chronic back pain. They found that “pain scores were similar throughout the 7-day application period” of the study, and “did not differ from day 3 to day 7 of the dosing interval during weeks 2 and 8.” Another study that looked at the efficacy of once-weekly Butrans in patients with osteoarthritis of the knee and/or hip found “similar mean pain scores throughout day 3 and day 7 of therapy” during the assessment period. Another study of patients with severe chronic low back pain found similarly consistent efficacy scores across the 7-day application period, as well as consistent use of supplemental analgesic medications.
Opioid-tolerant Patients with Breakthrough Cancer Pain Can Be Rapidly and Safely Titrated to Effective Doses of Fentanyl Sublingual Spray
In this study, opioid-tolerant cancer patients who experienced 1-4 daily episodes of breakthrough cancer pain were treated initially with 100 mcg of fentanyl sublingual spray and titrated up to a successful dose (max of 1600 mcg), defined as effective analgesia for two consecutive breakthrough cancer pain episodes. Median effective dose was 800 mcg. Based on Treatment Satisfaction Questionnaire for Medication scores, 89% of patients were satisfied, very satisfied, or extremely satisfied with fentanyl sublingual spray for breakthrough cancer pain at the end of titration (compared with 41% with their previous medication), with 90% reporting they were at least satisfied with the onset of effect of fentanyl sublingual spray.
Data Show OROS Hydromorphone ER May Have Less Abuse Potential than IR Hydromorphone
This study compared “the abuse-related effects of various formulations of hydromorphone, with particular emphasis on early time intervals after drug administration.” In the first phase, patients received each of the following: immediate-release (IR) hydromorphone 8 mg, intact OROS hydromorphone ER 16 and 32 mg, a milled preparation of OROS hydromorphone ER 8 mg, and placebo. Patients who tolerated each of these treatments received single doses of IR hydromorphone 8 mg and OROS hydromorphone ER 64 mg in the second phase. Researchers analyzed tie to maximum plasma concentration; area under the concentration-time curve (AUC) as baseline, 2, 4, and 6 hours; and other variables. The authors reported that plasma concentration rose more gradually and to lower maximum levels for the intact OROS hydromorphone ER compared to IR hydromorphone 8 mg and milled OROS hydromorphone ER. OROS hydromorphone ER also had a slower onset of effect and decreased reports of “high” and “euphoria” during the first two and four hours after dosing.