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5 Articles in Volume 3, Issue #4
Lidoderm Studied for New Applications
Osteoarthritis of the Temporomandibular Joint
Post-dural Puncture Headache Treatment
Preventing Post-dural Puncture Headache
Psychological Dimension of Pain Management

Lidoderm Studied for New Applications

While Lidoderm is currently FDA-approved only for the pain associated with postherpetic neuralgia (PHN), Phase IV studies suggest that Lidoderm has potential utility in a variety of chronic pain syndromes.

Editor’s note: this study was funded by and conducted under the auspices of Endo Pharmaceuticals. Preliminary results were presented at the 22nd Annual Scientific Meeting of the American Pain Society (APS) in March 2003. Principal investigators (grouped by specialty area) are: Vania Apkarian, MD (Post-Herpetic Neuralgia); Francis Burch, MD and Srinivas Nalamachu, MD (Osteoarthritis); Joe Gimbel, MD (Chronic Pain and Low Back Pain); Bruce Nicholson, MD and Mike Moskowitz, MD (Low Back Pain); and Bob Dworkin, MD (Idiopathic and Diabetic Neuropathy).

Introduction

An estimated 25 million Americans experience acute pain as a result of injury or surgery, and an estimated 50 million Americans suffer from chronic pain according to Joseph S. Gimbel, M.D., Arizona Research Center, Phoenix, Ariz., the principal investigator in two of the pilot studies. The most common chronic pain condition is back pain, which affects an estimated 36 million Americans. Pain can be relieved or greatly eased with proper pain management; however, most sufferers go untreated, under-treated, or improperly treated. Untreated pain can have significant physical, psychological and financial consequences by impacting daily functioning and quality of life. Pain costs Americans an estimated $100 billion each year due to lost wages and healthcare expenses. Pain is the leading cause of medically related work absenteeism, resulting in more than 50 million lost workdays each year. Researchers are continually evaluating and developing new pharmacologic interventions that may improve the quality of life for patients suffering with chronic pain. The following preliminary results show promising potential in mitigating pain in certain chronic pain syndromes.

About Lidoderm

Lidoderm® is a targeted topical analgesic patch that is applied directly to intact skin. Lidoderm® (lidocaine patch 5%) is currently FDA-approved for relief of pain associated with post-herpetic neuralgia, a chronic pain that can result from nerve damage by the herpes zoster virus, commonly referred to as shingles. Lidoderm® produces an analgesic effect by the penetration of lidocaine from the patch into intact skin, without complete loss of sensation or numbness. Lidoderm® should only be applied to intact skin. Reactions to Lidoderm® are generally mild and transient. During or immediately after treatment with Lidoderm®, the skin at the site of treatment may develop erythema or edema or may be the locus of abnormal sensation. Lidoderm® is contraindicated in patients with a known history of sensitivity to local anesthetics of the amide type, or to any other component product. The FDA-approved dosing for Lidoderm® is up to three patches applied for up to 12 hours within a 24-hour period. However, the safety and efficacy of Lidoderm® have not been established when used with dosing regimens above three patches per day. In clinical practice, a vast majority of patients are administered one Lidoderm® patch per day.

Cautions

While the preliminary data presented in the following sections suggest that Lidoderm® (lidocaine patch 5%) may provide pain relief and/or impact pain interference with quality of life in the four chronic pain conditions studied (post-herpetic neuralgia, diabetic neuropathy, osteoarthritis, and low back pain), Lidoderm is not currently FDA-approved for treatment of these conditions and the safety and efficacy of Lidoderm® have not been established. Experimental use of Lidoderm for these chronic pain syndromes at this stage of the FDA approval process is “off-label” and warrants extra caution during investigative use.

Postherpetic Neuralgia, Diabetic Neuralgia, and Low Back Pain

The first study was an open-label, multicenter, two-week pilot study designed to assess the impact of Lidoderm® (up to four patches every 24 hours) in patients with postherpetic neuralgia (PHN) (n=11), diabetic neuropathy (n=49), or low back pain (n=47) and who experienced a partial response to their current analgesic regimen that included gabapentin (Neurontin®). Using the Brief Pain Inventory (see Appendix A for source information) to assess pain interference with quality of life, the investigators found that the addition of Lidoderm® reduced pain interference with most measures in the PHN group (general activity, mood, normal work, sleep, enjoyment of life) and in all measures in the diabetic neuropathy and low back pain groups (general activity, mood, walking ability, normal work, relations with other people, sleep, enjoyment of life). In this study, Lidoderm® was well-tolerated, with relatively few clinical adverse events, most of which were mild to moderate. The most frequently reported treatment-related adverse events were somnolence and headache (2.8%).

Low Back Pain

In a separate nonrandomized, prospective, open-label, two-week pilot study of nonradicular acute/subacute (<3 months; n=20), short-term chronic (3-12 months; n=33), and long-term chronic (>12 months; n=76) low back pain sufferers, patients were treated for two weeks with up to four Lidoderm® patches every 24 hours to the area of maximal peripheral pain while continuing their current analgesic regimen without dosage adjustment. Using the Brief Pain Inventory to assess pain intensity and relief, investigators found that Lidoderm® produced significant improvements in pain intensity in all groups for worst pain, average pain, and pain right now, as well as significant improvements in least pain and pain relief for acute/subacute and long-term chronic groups. All groups showed significant reductions in the Brief Pain Inventory composite score for pain interference with quality of life and the Beck Depression Inventory score (see Appendix A for source information). The lidocaine patch 5% was well tolerated, with mild-to-moderate application site reactions (e.g., erythema, irritation, edema, paresthesia, puritis) being the most commonly reported treatment-related adverse event (13%). There were no serious systemic adverse events or drug-drug interactions related to treatment.

Diabetic Neuropathy

Painful diabetic neuropathy, which occurs in 20-24% of patients with diabetes, includes a variety of painful sensations such as tingling or burning of the lower extremities, either with or without allodynia (pain caused by normally non-painful stimuli such as rough clothing or light touch). In a prospective, nonrandomized, three-week, open-label pilot study of 56 diabetic neuropathy patients, up to four Lidoderm® patches were applied for 18 hours per day to areas of maximal peripheral neuropathic pain. Patients continued their current analgesic medication, without dosing adjustment. The results suggest that Lidoderm® produced significant improvements in pain intensity, pain relief, and pain interference with quality of life both in patients with allodynia (n=19) and without allodynia (n=37). No systemic adverse events or drug-drug interactions related to the lidocaine patch 5% were reported. The most frequently reported adverse event was mild application site burning (10%).

Osteoarthritis Knee Pain

In a nonrandomized, prospective, open-label, multicenter, two-week study designed to assess the effectiveness and safety of Lidoderm® as monotherapy in patients with osteoarthritis (OA) of one or both knees (average daily pain intensity >4 on a 0-10 pain scale), 32 patients were treated with up to four Lidoderm® patches every 24 hours covering as much of the painful area as possible; all other analgesics were discontinued before entering the study. Investigators reported significant improvements in pain, stiffness, and physical function as measured by the Western Ontario and McMaster Universities (WOMAC) OA index scores (see Appendix A for source information). All seven domains of pain interference with quality of life (general activity, mood, walking, work, relations, sleep, and enjoyment of life) measured by the Brief Pain Inventory were significantly improved with the use of Lidoderm® monotherapy. Global assessments of patch satisfaction and pain relief showed that 82% of patients and 76% of investigators rated Lidoderm® patch satisfaction as “satisfied” to “very satisfied” and pain relief as moderate to complete. In this study, the lidocaine patch was well-tolerated, with no reports of systemic adverse events. There were two reports of local application site reactions (very slight erythema and petechiae, which led to one patient dropping out of the study).

Summary

Endo Pharmaceuticals Inc. released new data from four pilot Phase IV studies at the 22nd Annual Scientific Meeting of the American Pain Society (APS). These preliminary data suggest that Lidoderm® (lidocaine patch 5%) may provide pain relief and/or impact pain interference with quality of life in four chronic pain conditions. Further large scale studies are to be conducted to verify safety and efficacy of Lidoderm in the treatment of postherpetic neuralgia, diabetic neuralgia, low back pain, and osteoarthritis knee pain.

Appendix A. Assessment Instruments

The Brief Pain Inventory (BPI)

The Brief Pain Inventory was developed in 1989 by Dr. Charles Cleeland PhD for rapid assessment of the severity and impact of pain in cancer patients. The BPI has since been translated into more than two dozen languages, and is widely used in both research and clinical settings. This instrument is available in both standard and short form and is used to record pain assessments, interventions, and outcomes. The inventory is self-administered and periodically repeated to record pain assessments over time.

1. Brief pain inventory [BPI] (1991). Cleeland CS IN: Turk DC & Melzack R (1992). Handbook of pain assessment. New York: Guilford Press. Pg.367-370,378-382

2. Brief pain inventory short form [BPI SF] (1991). Cleeland CS IN: Turk DC & Melzack R (1992). Handbook of pain assessment. New York: Guilford Press. Pg.367-370,383-384

Beck Depression Inventory®-II (BDI®-II)

The Beck Depression Inventory®-II, published in 1996, is a widely used instrument, for detecting depression over a prior two week period and typically takes about five minutes to complete. It consists of 21 items to assess the intensity of depression in patients. Each item is a list of four statements arranged in increasing severity about a particular symptom of depression and is applicable for patients aged 13 through 80 years old.

Beck Depression Inventory and BDI are U.S. registered trademarks of The Psychological Corporation registered in the United States of America and/or other jurisdictions. For further information: The Psychological Corporation, 19500 Bulverde Road, San Antonio, Texas 78259; 1-800-228-0752.; http://www.psychcorp.com.

WOMACTM 3.1 Index

The WOMACTM 3.1 Index is a knee and hip osteoarthritis index. This assessment is self-administered and gauges the three dimensions of pain, disability and joint stiffness using a list of 24 questions. This index, having been subjected to numerous validation studies, is considered a valid, reliable and responsive measure of outcome, and has been used in diverse clinical and interventional environments. For further information refer to the following website: http://www.womac.org/womac/

Last updated on: May 16, 2011
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