St. John’s Wort May Thwart Opioid Analgesia

Chronic pain is often associated with depression and many herbal over-the-counter remedies for self-treatment of depression or anxiety contain St. John’s wort. New research suggests that taking this herbal product can incur drug interactions that may reduce effects of oxycodone and many other opioid analgesics.

Researchers in Finland designed a randomized, placebo-controlled, cross-over trial in which 12 healthy subjects were administered either St. John’s wort or placebo three-times daily for 15 days and given oral oxycodone hydrochloride 15 mg on day 14 [Nieminen et al. 2010]. Following St. John’s wort administration oxycodone plasma concentration was significantly decreased by 50% and its half-life was shortened by 27%, resulting in the self-reported drug effects of oxycodone decreasing significantly (p=0.004). The authors conclude that this interaction of St. John’s wort and oxycodone could be of clinical significance when treating patients with chronic pain.

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Chronic Pain Linked to Low Vitamin D in Men

Research on the association of vitamin D status with pain conditions continues to accumulate. In this latest study, a multinational European group of researchers found in a large sample of men that having musculoskeletal pain, particularly chronic widespread pain, was significantly influenced by low levels of vitamin D.

As part of the extensive European Male Ageing Study (EMAS), men 40 to 79 years of age completed a mailed pain assessment questionnaire and attended a clinical assessment that included measurement of vitamin D status signified by 25-hydroxyvitamin D3, or 25(OH)D, levels [McBeth et al. 2010]. Subjects were classified according to 25(OH)D levels as “normal” (≥15 ng/ml) or “low” (<15 ng/ml). Of 3,075 male participants included in the analysis (mean age 60 years, primarily Caucasian), 1,262 (41.0%) were pain-free, 1,550 (50.4%) reported “other pain” that did not satisfy criteria for chronic widespread pain (CWP), and 263 (8.6%) reported CWP. Compared with patients who were pain-free, those with “other pain” and those with CWP had significantly lower 25(OH)D levels (p<0.05).

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Study Supports Tai Chi for Fibromyalgia Pain

Fibromyalgia is typically managed with a multifaceted approach involving pharmacotherapy, psychological counseling, education, and exercise. Now, new research published in the New England Journal of Medicine suggests that the ancient Chinese practice of tai chi may offer significant and extensive benefits.

Researchers at Tufts University Medical Center in Boston, Mass., conducted a single-blind trial enrolling patients diagnosed with fibromyalgia who were randomly assigned to either classic Yang-style tai chi (n=33, 85% female) as compared with a control intervention consisting of wellness education and stretching (n=33, 88% female). All participants were 50 years of age, on average, and each group had 60-minute twice-weekly sessions for 12 weeks.

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Pharmacotherapies for Neuropathic Pain Reviewed

Chronic neuropathic pain can be caused by a variety of disorders and pharmacologic management is an important option; however, results are often unsatisfactory. An updated review of the research literature examines efficacy and safety data on currently available agents, finding that tricyclic antidepressants and opioids may be first-line therapies for a number of neuropathic conditions.

To extend their earlier evidence review conducted in 2005, researchers in Denmark searched MEDLINE and EMBASE for randomized, double-blind, placebo-controlled trials (RCTs) examining pharmacotherapies for 6 different neuropathic pain conditions. They identified 174 studies for inclusion, representing a 66% increase in published RCTs on this subject in just the past 5 years. Painful polyneuropathy (most often due to diabetes) was examined in 69 studies and postherpetic neuralgia in 23, while peripheral nerve injury, central pain, HIV neuropathy, and mixed neuropathic pain were less often studied.

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U.S. FDA Delays Opioid REMS Until 2011

According to an exclusive report in Medscape Medical News, the U.S. Food and Drug Administration (FDA) will not unveil its risk evaluation and mitigation strategies (REMS) for opioid analgesics until 2011. This announcement comes shortly after the FDA’s advisory committee rejected initial plans late last month and all indications are that opioid REMS, when finally implemented, could dramatically change the prescribing of opioids for the millions of Americans who benefit from these pain relievers.

In the Medscape report [available here], Karen Mahoney, from the FDA’s Center for Drug Evaluation and Research, says: "FDA is currently reviewing the input from the advisory committee and the public. We have not yet made any final decisions on the REMS program. Once final decisions are made, FDA will communicate these requirements to the manufacturers, and they will have up to 120 days to submit a program for FDA's review and approval."

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Women Suffer Chronic Pain More Than Men

According to a recent conference presentation, women experience chronic pain longer, more intensely, and more often than men. Attending to both the physical and mental suffering of women with chronic pain may be critical for successful treatment outcomes.

Speaking on August 13, 2010 at the 118th Annual Convention of the American Psychological Association in San Diego, CA, Jennifer Kelly, PhD, from the Atlanta Center for Behavioral Medicine, said, “Chronic pain affects a higher proportion of women than men around the world [and] we need to encourage women to take a more active role in their treatment and reduce the stigma and embarrassment of this problem.” Fibromyalgia, irritable bowel syndrome, rheumatoid arthritis, and migraines are more prevalent in women than in men, and women also are more likely to have multiple, concurrent painful conditions leading to greater psychological distress and disability.

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Monitoring, Counseling Curb Rx-Opioid Misuse

Patients with chronic pain who show aberrant drug-related behaviors, or an inclination toward such misbehaviors, often are denied treatment or discontinued from treatment when they are noncompliant with their use of prescribed opioid analgesics. New research demonstrates that close monitoring and substance-misuse counseling may facilitate compliance with opioid analgesic therapy in even the most difficult patients.

Researchers at the Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, conducted a randomized controlled trial in patients who were prescribed opioids for chronic noncancer back pain and who showed risk potential for or actual demonstration of opioid misuse [Jamison et al. 2010]. Forty-two patients meeting criteria for a high-risk of opioid misuse were randomized to either usual treatment (High-Risk Control, n=21) or experimental compliance treatment consisting of monthly urine screens, compliance checklists, and individual and group motivational counseling (High-Risk Experimental, n=21). An additional group of patients who met criteria indicating low potential for opioid misuse were recruited to second control group (Low-Risk Control, n=20). Patients were followed for 6 months and completed pre- and post-study questionnaires and monthly electronic diaries.

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Criteria for Diagnosing Early-Stage RA Published

An estimated 1.3 million Americans have rheumatoid arthritis (RA), and recent evidence suggests that early, aggressive treatment can be important. Prior criteria for diagnosing RA from the American College of Rheumatology (ACR) have been criticized for not detecting early-stage disease processes, delaying treatment in many patients who might benefit, and a newly published approach seeks to remedy these deficiencies.

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“John Henryism” & Pain-Relief Deficits in Women

Despite an increasing prevalence of chronic pain and the many therapeutic modalities to manage it, new research shows inadequate pain assessment and treatment in primary care settings, particularly when it comes to female patients but also among African Americans. Along with that, women exhibit less effective skills for coping with their pain, measured in this study as “John Henryism.”

According to prior literature, women and racial/ethnic minorities are particularly vulnerable to suboptimal assessments of their pain (whether acute, chronic, or cancer pain) and their complaints of pain receive less attention from healthcare providers leading to undertreatment. To further examine these issues, researchers at the University of Michigan Medical School, Ann Arbor, MI, enrolled a convenience sample of 128 patients younger than age 50 referred to their tertiary-care center for the assessment and treatment of chronic pain lasting about 5 years [Green and Hart-Johnson 2010]. Subjects, all of whom completed a battery of assessment instruments about their prior treatment, were 47% African American and 60% female. Here are highlights of the study results reported in the August 2010 issue of The Journal of Pain:

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Brain Changes in IBS and FMS Reported

Research studies continue to uncover structural and functional brain changes associated with chronic pain syndromes. A pair of newly reported imaging investigations update such brain changes in irritable bowel syndrome (IBS) and fibromyalgia syndrome (FMS).

In our continuing series on “Pain and the Great Brain Robbery!” we have previously written about research describing brain changes in IBS and FMS, and these two latest studies add to that knowledge. However, it should be recognized that, while the specific brain structures involved might be of most interest only to neuroscientists and somewhat confusing to others, an appreciation of the underlying principle that structural and functional brain changes strongly affect patients with chronic pain disorders and influence their care should be of importance for all healthcare providers.

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Destroy Nerves to Relieve Arthritic Back Pain?

New research suggests that adhering to common interventional approaches for diagnosing arthritis-related back pain may result in excessive tests, delays in pain relief, and wasteful spending. A recommended course is to skip diagnostic nerve blocks altogether and move straight to denervation (nerve destroying) treatments when arthritis is suspected as causing nonspecific back pain… but there are some reservations.

Current estimates are that about 10% to 15% of patients with spinal (axial) low-back pain have arthritis of the vertebral facet joints. However, this condition is difficult to precisely diagnose because findings on x-rays or MRIs often do not correspond with the degree of back pain. This has led to routinely performing temporary diagnostic nerve blocks (by injecting numbing agents) to establish the arthritis connection before recommending radiofrequency denervation, which essentially stems pain signals by burning the nerves serving affected facet joints [see illustration]. Facet-joint interventions are the second most frequently performed procedures in pain clinics across the United States and, according to new research, it may be appropriate in many cases and more cost-effective to go directly to denervation without first performing diagnostic nerve-blocks to confirm the root cause of the problem.

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Safety, Efficacy of TOPICAL NSAIDs Examined

Superficially applied (topical) nonsteroidal anti-inflammatory drugs (NSAIDs) are often used for musculoskeletal strains, sprains, and pains. Their main appeal is presumed safety in providing pain relief without NSAID-associated systemic adverse effects; however, this needs careful consideration, especially in older persons.

Thomas Massey, from the University of Oxford, United Kingdom, and colleagues conducted a Cochrane Systematic Review to evaluate the evidence from randomized, double-blind, controlled trials of the efficacy and safety of topically applied NSAIDs for relief of acute pain [Massey et al. 2010]. Inclusion criteria were controlled trials in adults with strains, sprains, or sports or overuse-type injuries, with 10 or more participants in each treatment group, and treatment application at least once daily. They identified 47 qualifying studies, enrolling a total of 3,455 participants, and comparing topical NSAID gel, spray, or cream versus a similar placebo.

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Aug2010 – Pain Product Announcements & Warnings

Featured Items: buprenorphine transdermal patch (Butrans) approval, leflunomide (Arava) safety warning, quinine sulfate (Qualaquin) safety warning. — Brand names are trademarks of their respective manufacturers. Compiled by Winnie Dawson, MA, RN, BSN.

Buprenorphine Transdermal System (Butrans™) – Receives FDA Approval
The FDA and Purdue Pharma, the maker of Butrans, announced a July 2010 approval of a transdermal system for the management of moderate to severe chronic pain in patients requiring continuous opioid analgesia. This unique formulation of buprenorphine — preceded by the parenteral form approved in 1981 — acts as a partial agonist at mu-opioid receptors and as an antagonist at kappa receptors. Each Butrans transdermal patch delivers continuous-release analgesia for 7 days; patches are available in 5, 10, and 20 mcg/hour strengths. Four 12-week double-blind, controlled clinical trials in both opioid-naïve and opioid-experienced patients with moderate to severe chronic low back pain or osteoarthritis helped to demonstrate Butrans’ efficacy for pain reduction. The most common adverse effects were gastrointestinal disturbances, various application-site irritations, headache, dizziness, somnolence, and dry mouth. Clinicians should visit http://www.butrans.com/ to read the Prescribing Information and Medication Guide for further details, including contraindications and precautions.

Leflunomide (Arava®) — FDA Adds Warnings
Following a post-marketing review of adverse event reports, the FDA has required an additional drug-use warning for leflunomide. The drug, used to treat rheumatoid arthritis, can increase patient risk for severe liver injury. The decision was based on a review of adverse event reports which identified 49 cases of severe liver injury, 14 of which resulted in death. The risk appears to be greater in patients with pre-existing liver disease or those who use additional drugs known to cause liver injury. Healthcare professionals are advised to assess patients thoroughly before prescribing leflunomide. For more information, see the FDA Drug Safety Communication released in July 2010.

Quinine Sulfate (Qualaquin™) — Safety Warning
The FDA issued a July 2010 warning to alert practitioners that the off-label use of Qualaquin for night-time leg cramps may result in serious and life-threatening hematological reactions. While the product is FDA-approved for the treatment of uncomplicated parasitic malaria, it has been sometimes used in the U.S. for relief of pain associated with night-time leg cramps. Adverse reactions of thrombocytopenia and hemolytic-uremic syndrome with permanent kidney damage have been reported. The FDA warns prescribers against the use of Qualaquin for unapproved uses and encourages health practitioners to alert patients to the warning signs of thrombocytopenia when prescribing for approved indications. The FDA Drug Safety Communication provides additional information.