Pregabalin add-on for Neuropathic Pain in Cervical Myelopathy

Comparison of Effectiveness of Opioid Only and Pregabalin add-on for the Treatment of Neuropathic Pain in Cervical Myelopathy Patients

There is no information on the effect of pregabalin in patients with neuropathic pain in cervical myelopathy under routine clinical practice. The investigators will conduct this prospective, randomized trial to determine the efficacy of pregabalin for neuropathic pain in cervical myelopathic patients in order to validate or refute this popular practice. The primary aim of this study was to compare Leeds assessment of neuropathic symptoms and signs scale (LANSS) scores of neuropathic pain in cervical myelopathy patients.

Neuropathic pain is a well-recognized clinical entity. It is defined as pain caused by the lesion or dysfunction of the peripheral or central nervous system, and it can be diagnosed by well-established clinical criteria. Neuropathic pain is caused by lesions or dysfunction of the nervous system and is initiated by several cellular and molecular mechanisms. Compression of neural and neurovascular structures may result in neuropathic pain. Although a number of therapies are available for neuropathic pain, including antidepressants, tramadol, opioids, and different antiepileptic drugs, the results of a recent systematic review suggest that, in view of their balance between efficacy and tolerability, pregabalin can be regarded as first line treatments for peripheral pain with a neuropathic component. Pregabalin is one of antiepileptic drugs (AEDs) that have been studied in the treatment of a wide variety of disorders, such as neuropathic pain, epilepsy, spasticity, and anxiety. The use of AEDs in the treatment of neuropathic pain is based on a number of similarities in the pathophysiologic and biochemical mechanisms underlying neuropathic pain and epilepsy. Its use for the treatment of several neuropathic pain syndromes is common, and it is approved by the Food and Drug Administration (FDA) for the treatment of diabetic neuropathy, post-herpetic neuralgia, fibromyalgia and spinal cord injury, a model of central neuropathic pain. The off-label use of pregabalin for the various pain syndromes in general, and for neuropathic pain in particular, is ubiquitous. However, minimal support for this practice exists in the literature and its cost is perhaps exorbitant. There is no information on the effect of pregabalin in patients with neuropathic pain in cervical myelopathy under routine clinical practice.

Patients in the opioid group received the only opioid (5mg of oxycodone three times a day) for 8 weeks.

Patients in the pregabalin add-on group received 75mg of pregabalin twice a day for the first week (150 mg/day) and 150mg of pregabalin twice a day (300 mg/day) for the second week and 300mg of pregabalin twice a day (600mg/day) for subsequent 6 weeks.

Patients in the pregabalin add-on group received 75mg of pregabalin twice a day for the first week (150 mg/day) and 150mg of pregabalin twice a day (300 mg/day) for the second week and 300mg of pregabalin twice a day (600mg/day) for subsequent 6 weeks.

Patients in the opioid group received the only opioid (5mg of oxycodone three times a day) for 8 weeks.

The LANSS pain scales are used globally to screen for the presence of pain of neuropathic origin because they have high sensitivity and specificity compared with other available tools. It rages from 0 to 24. The LANSS scores ≧12 suggest the presence of neuropathic pain. The visual analogue scale or visual analog scale (VAS) is a psychometric response scale which can be used in questionnaires. It is a measurement instrument for subjective characteristics or attitudes that cannot be directly measured. When responding to a VAS item, respondents specify their level of agreement to a statement by indicating a position along a continuous line between two end-points. It ranges from 0 to 10 (0 means no pain, 10 means worst pain.

The NDI is a modification of the Oswestry Low Back Pain Disability Index. It is a patient-completed, condition-specific functional status questionnaire with 10 items including pain, personal care, lifting, reading, headaches, concentration, work, driving, sleeping and recreation. It ranges from 0 to 45 (0 means no disability, 45 means severe disability). The EQ-5D is a generic, self-completed, easy-to-use questionnaire. The EQ-5D comprises five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Rated level can be coded as a number 1, 2, or 3, which indicates having no problems for 1, having some problems for 2, and having extreme problems for 3. As a result, a person's health status can be defined by a 5-digit number, ranging from 11111 (having no problems in all dimensions) to 33333 (having extreme problems in all dimensions). There are potentially 243 (=35) different health states.

Inclusion Criteria: between the ages of 18 to 80 years Among patients with cervical myelopathy, patients with neuropathic pain (LANSS pain scale ≥ 12) Completing 8-week drug trial Exclusion Criteria: Current or prior gabapentin or pregabalin use Chronic use of narcotic pain medications Chronic depression or the use of anti-depressants History of addiction and/or substance abuse Presence of significant motor deficits, and /or bowel and/or bladder dysfunction Known renal insufciency, diabetes, congestive heart failure, cardiac conduction abnormalities, and thrombocytopenia