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Symptomatic Treatment of Neuropathic Pain: A Focus on the Role of Anticonvulsants

  • Authors: Faculty: Ahmad Beydoun, MD
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Target Audience and Goal Statement

This continuing medical education activity is intended for neurologists and pain specialists who diagnose and treat patients with neuropathic pain.

Neuropathic pain is defined as pain initiated by a primary lesion or dysfunction of the nervous system and can present a major therapeutic challenge to clinicians. In general, the elderly community and patients dealing with chronic illnesses are at an increased risk for developing this disorder. Recognized types of neuropathic pain include trigeminal neuralgia, peripheral neuropathies (i.e., diabetic, uremic, and AIDS-related), and post-herpetic and entrapment neuropathies. Antidepressants, opioid and analgesic medications, and early anticonvulsants have traditionally been used with varying levels of success and have been limited primarily by their side-effect profiles. Ion channel blockers and agents capable of influencing neurotransmitter action constitute the focus of modern treatment strategies. Newer anticonvulsants have shown significant improvements in efficacy and tolerability in early trials, although further studies are still required.

This complimentary continuing education activity will discuss the epidemiology and pathophysiology of neuropathic pain and review recent clinical trials that support the efficacy of newer anticonvulsant drugs in its management.

Upon completion of this educational activity, participants will be able to:

  1. Define the classification and clinical manifestations of neuropathic pain

  2. Describe the pathophysiology of neuropathic pain

  3. Explain the mechanism of action of anticonvulsant drugs in the management of this pain type

  4. Review key clinical trial data and current evidence-based therapeutic options

  5. Develop and effectively utilize a treatment algorithm that deals with appropriate drug selection and titration in treating the various neuropathic pain syndromes


  • Ahmad Beydoun, MD

    Associate Professor of Neurology, Director, Epilepsy Program and Investigational, Antiepileptic Drugs Trial, University of Michigan Health Systems, Ann Arbor, Michigan


    Disclosure: Grant/Research Support: Parke-Davis, Novartis Pharmaceuticals Corporation, Abbott Laboratories, Glaxo Wellcome, Inc.
    Speakers Bureau: Parke-Davis, Novartis Pharmaceuticals Corporation, Abbott Laboratories, Glaxo Wellcome, Inc.

Accreditation Statements

    For Physicians

  • The Strategic Institute for Continuing Health Care Education is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

    The Strategic Institute for Continuing Health Care Education designates this continuing medical education activity for a maximum of 1 hour in category 1 credit toward the AMA Physician's Recognition Award. Each physician should claim only those hours of credit that he/she actually spent in the educational activity.

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For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]

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This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page.

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Symptomatic Treatment of Neuropathic Pain: A Focus on the Role of Anticonvulsants

Authors: Faculty: Ahmad Beydoun, MDFaculty and Disclosures


Neuropathic Pain Syndromes: Types and Pain-Sustaining Mechanisms

  • This is really going to be an evidence-based approach to the treatment of neuropathic pain. That is, a review of the results of randomized, double-blind, placebo-controlled clinical trials that were done, and that either support or fail to support the variety of classes of drugs that we tend to use for the treatment of these disorder.

  • Symptomatic Treatment of Neuropathic Pain


    Symptomatic Treatment of Neuropathic Pain

    (Enlarge Slide)
  • There are a number of neuropathies that are associated with pain. Perhaps the most common in the western world is painful diabetic neuropathy. But you also have other metabolic neuropathies that can be associated with pain, such as alcoholic neuropathy. Then [there are] the neuralgias, such as trigeminal (TN) and post-herpetic neuralgias (PHN).

    In the case of sympathetically maintained pain [there are] the complex regional pain syndromes, type 1 being what used to be referred to as reflex sympathetic dystrophy and type 2 being the causalgias. And then [there are] other conditions such as phantom limb pain, as well as central pain following [central nervous system lesions] such as stroke.

  • Types of Neuropathic Pain Syndromes


    Types of Neuropathic Pain Syndromes

    (Enlarge Slide)
  • Just as a background we are going to briefly review the neuroanatomy of the pain pathways. There are a number of receptors known as nociceptors because they preferentially react to noxious stimuli whether they are thermal, mechanical or chemical. These are known as the A-delta fibers, which are lightly myelinated fiber[s] and the C fibers, which are unmyelinated fibers. The A-delta and C fibers synapse in the dorsal horn, preferentially in lamina[s] 1, 2 and 5.

    From there they cross to the other side of the spinal cord and ascend in the spinothalamic tract until they synapse in the thalamus preferentially in the ventroposterolateral (VPL) nucleus from which they make a secondary connection in the sensory cortex, which is responsible for the sensory component of pain, as well as in the limbic forebrain system that accounts for the emotional component of pain.

    There are also 2 important descending inhibitory pathways from the brainstem to the spinal cord. The first originate[s] at the level of the midbrain in the periaqueductal gray and it has predominantly serotonin its major neurotransmitter. The other originates at the level of the locus ceruleus in the medulla and it has norepinephrine as the major neurotransmitter.

  • Neuroanatomy of Pain Pathways


    Neuroanatomy of Pain Pathways

    (Enlarge Slide)
  • A number of mechanisms have been postulated [for] maintaining neuropathic pain. In the past, we tended to focus mostly on the peripheral changes that occurred following deafferentation. And basically what you have is an upregulation of the sodium channel. There are a number of sodium channels that are created at areas of demyelination or axonal injury. As a result, the way to treat peripheral sensitization, which is characterized by decreased threshold and ectopic discharges, is by giving a sodium channel modulator.

    But perhaps as important [are] the changes that occur more [rostrally] at the level of the spinal cord. Very early on following a peripheral nerve injury, the dorsal horn gets bombarded by a variety of neurotransmitters. Glutamate and aspartate, which are excitatory transmitters, interact with the N-methyl-D-aspartate (NMDA) receptors and [substance P and] neurokinin interacts with the neurokinin type 1 (NK1) receptors. This leads to calcium entry into the cell. Calcium acts as a very important secondary messenger. It activates nitric oxide synthetase which leads to the synthesis of nitric oxide. It leads to immediate early gene expression [(c-fos and c-jun)] and it also activates a number of [phospholipases], that phosphorylate a number of receptors at the level of the dorsal horn decreasing its threshold and leading to ectopic discharges, a phenomenon known as central sensitization.

    And in order to treat central sensitization you are going to have to use NMDA-blocking agents, NK1- or substance P-blocking agents, or calcium channel modulators.

  • Postulated Mechanisms in Sustaining Neuropathic Pain


    Postulated Mechanisms in Sustaining Neuropathic Pain

    (Enlarge Slide)