SciCombinator

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Concept: Pregabalin

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Previous studies have documented strategies to promote off-label use of drugs using journal publications and other means. Few studies have presented internal company communications that discussed financial reasons for manipulating the scholarly record related to off-label indications. The objective of this study was to build on previous studies to illustrate implementation of a publication strategy by the drug manufacturer for four off-label uses of gabapentin (Neurontin, Pfizer, Inc.): migraine prophylaxis, treatment of bipolar disorders, neuropathic pain, and nociceptive pain.

Concepts: Pharmacology, Pain, Caffeine, Postherpetic neuralgia, Pregabalin, Neuropathic pain, Gabapentin, Off-label use

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Background Sciatica can be disabling, and evidence regarding medical treatments is limited. Pregabalin is effective in the treatment of some types of neuropathic pain. This study examined whether pregabalin may reduce the intensity of sciatica. Methods We conducted a randomized, double-blind, placebo-controlled trial of pregabalin in patients with sciatica. Patients were randomly assigned to receive either pregabalin at a dose of 150 mg per day that was adjusted to a maximum dose of 600 mg per day or matching placebo for up to 8 weeks. The primary outcome was the leg-pain intensity score on a 10-point scale (with 0 indicating no pain and 10 the worst possible pain) at week 8; the leg-pain intensity score was also evaluated at week 52, a secondary time point for the primary outcome. Secondary outcomes included the extent of disability, back-pain intensity, and quality-of-life measures at prespecified time points over the course of 1 year. Results A total of 209 patients underwent randomization, of whom 108 received pregabalin and 101 received placebo; after randomization, 2 patients in the pregabalin group were determined to be ineligible and were excluded from the analyses. At week 8, the mean unadjusted leg-pain intensity score was 3.7 in the pregabalin group and 3.1 in the placebo group (adjusted mean difference, 0.5; 95% confidence interval [CI], -0.2 to 1.2; P=0.19). At week 52, the mean unadjusted leg-pain intensity score was 3.4 in the pregabalin group and 3.0 in the placebo group (adjusted mean difference, 0.3; 95% CI, -0.5 to 1.0; P=0.46). No significant between-group differences were observed with respect to any secondary outcome at either week 8 or week 52. A total of 227 adverse events were reported in the pregabalin group and 124 in the placebo group. Dizziness was more common in the pregabalin group than in the placebo group. Conclusions Treatment with pregabalin did not significantly reduce the intensity of leg pain associated with sciatica and did not significantly improve other outcomes, as compared with placebo, over the course of 8 weeks. The incidence of adverse events was significantly higher in the pregabalin group than in the placebo group. (Funded by the National Health and Medical Research Council of Australia; PRECISE Australian and New Zealand Clinical Trials Registry number, ACTRN12613000530729 .).

Concepts: Clinical trial, Neurology, Placebo, Randomness, Randomization, Outcome, Pregabalin, Neuropathic pain

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PURPOSE: Pregabalin (PRG) is approved for the treatment of neuropathic pain, partial seizures and generalised anxiety disorder in many countries and currently under study for other indications. Supported by case reports and the results of a limited number of studies there is an ongoing debate on the potential of PRG to cause addictive behaviours. However, currently available evidence on this issue is sparse, and any definitive assessment of PRG’s potential for abuse and dependence is not yet in sight. The aim of our study was to identify the number of cases of PRG abuse or dependence reported to the database of a German medical regulatory body and to obtain insights into further usage-specific parameters. METHODS: We conducted a query of the entire database of the German Federal Institute for Drugs and Medical Devices (BfArM) regarding reports of PRG abuse or dependence and analysed these cases on the basis of several parameters. RESULTS: A total of 55 reports of PRG abuse or dependence were identified (mean age 36 years, 64 % of reports involved males). The first reports were submitted to BfArM in 2008, and the reporting frequency has increased up to the present. Mean daily PRG dosage was 1424 mg. Current or previous polytoxicomania was present in 40 and 42 % of cases, respectively. Psychiatric diagnoses other than substance-related disorders were reported in 13 (24 %) cases. In about one-third of the patients withdrawal syndromes subsequent to discontinuation of PRG were reported. CONCLUSIONS: Cases of PRG abuse or dependence have been reported to the BfArM since 2008, with a marked increase of such reports in subsequent years. Male sex and a history of polytoxicomania may be possible risk factors for the development of addictive behaviours related to PRG.

Concepts: Drug addiction, Addiction, Antidepressant, Generalized anxiety disorder, Panic disorder, Physical dependence, Withdrawal, Pregabalin

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To examine the risk to heroin users of also using gabapentin or pregabalin (gabapentoids).

Concepts: Heroin, Pregabalin, Gabapentin, Poly drug use, Speedball

5

The gabapentinoid drugs gabapentin and pregabalin are key front-line therapies for various neuropathies of peripheral and central origin. Originally designed as analogs of GABA, the gabapentinoids bind to the α 2 δ-1 and α 2 δ-2 auxiliary subunits of calcium channels, though only the former has been implicated in the development of neuropathy in animal models. Transgenic approaches also identify α 2 δ-1 as key in mediating the analgesic effects of gabapentinoids, however the precise molecular mechanisms remain unclear. Here we review the current understanding of the pathophysiological role of the α 2 δ-1 subunit, the mechanisms of analgesic action of gabapentinoid drugs and implications for efficacy in the clinic. Despite widespread use, the number needed to treat for gabapentin and pregabalin averages from 3 to 8 across neuropathies. The failure to treat large numbers of patients adequately necessitates a novel approach to treatment selection. Stratifying patients by sensory profiles may imply common underlying mechanisms, and a greater understanding of these mechanisms could lead to more direct targeting of gabapentinoids.

Concepts: Nervous system, Opioid, Pain, Analgesic, Peripheral neuropathy, Pregabalin, Neuropathic pain, Gabapentin

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The pathogenesis of fibromyalgia (FM) has not been clearly elucidated, but central sensitization, which plays an important role in the development of neuropathic pain, is considered to be the main mechanism. The cutaneous silent period (CSP), which is a spinal reflex mediated by A-delta cutaneous afferents, is useful for the evaluation of sensorimotor integration at the spinal and supraspinal levels. To understand the pathophysiology of FM, we compared CSP patterns between patients with FM and normal healthy subjects. Twenty-four patients with FM diagnosed in accordance with the 1990 American College of Rheumatology classification system and 24 age- and sex-matched healthy volunteers were recruited. The CSP was measured from the abductor pollicis brevis muscle. Demographic data, number of tender points, and visual analog scale and FM impact questionnaire scores were collected. The measured CSP and clinical parameters of the patient and control groups were compared. In addition, possible correlations between the CSP parameters and the other clinical characteristics were analyzed. Mean CSP latencies did not differ between patients (55.50 ± 10.97 ms) and healthy controls (60.23 ± 11.87 ms; p = 0.158), although the mean CSP duration was significantly longer in patients (73.75 ± 15.67 ms) than in controls (63.50 ± 14.05 ms; p = 0.021). CSP variables did not correlate with any clinical variables. The significantly longer CSP duration in FM patients suggests central dysregulation at the spinal and supraspinal levels, rather than peripheral small fiber dysfunction.

Concepts: Patient, Correlation and dependence, Irritable bowel syndrome, Fibromyalgia, Pregabalin, Gabapentin, Adductor pollicis muscle, Abductor pollicis brevis muscle

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Hospice/palliative care patients may differ from better studied populations, and data from other populations cannot necessarily be extrapolated into hospice/palliative care clinical practice. Pharmacovigilance studies provide opportunities to understand the harms and benefits of medications in routine practice. Gabapentin, a γ-amino butyric acid analogue antiepileptic drug, is commonly prescribed for neuropathic pain in hospice/palliative care. Most of the evidence however relates to non-malignant, chronic pain syndromes (diabetic neuropathy, postherpetic neuralgia, central pain syndromes, fibromyalgia). The aim of this study was to quantify the immediate and short-term clinical benefits and harms of gabapentin in routine hospice/palliative care practice.

Concepts: Pharmacology, Neurology, Pain, Cultural studies, Chronic pain, Peripheral neuropathy, Pregabalin, Gabapentin

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To examine medication adherence and healthcare costs for combination prescription initiators (duloxetine/milnacipran/venlafaxine with pregabalin) versus monotherapy initiators (duloxetine, milnacipran, venlafaxine, and pregabalin) among patients with fibromyalgia syndrome (FMS).

Concepts: Pharmacology, Prescription drug, Syndromes, Fibromyalgia, Generalized anxiety disorder, Pregabalin, Gabapentin, Duloxetine

1

The anticonvulsant pregabalin promotes neural regeneration in a mouse model of spinal cord injury (SCI). We have also previously observed that anticonvulsants improve motor outcomes following human SCI. The present study examined the optimal timing and type of anticonvulsants administered in a large, prospective, multi-center, cohort study in acute SCI. Mixed-effects regression techniques were used to model total motor scores at 1, 3, 6, and 12 months post injury. We found that early (not late) administration of anticonvulsants significantly improved motor recovery (6.25 points over 1 year). The beneficial effect of anticonvulsants remained significant after adjustment for differences in 1-month motor scores and injury characteristics. A review of a subset of patients revealed that gabapentinoids were the most frequently administrated anticonvulsant. Together with preclinical findings, intervention with anticonvulsants represents a potential pharmacological strategy to improve motor function after SCI.

Concepts: Better, Cohort study, Spinal cord, Improve, Philosophy of science, Set theory, Anticonvulsant, Pregabalin

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Gabapentinoid (pregabalin and gabapentin) abuse is increasingly being reported.

Concepts: Pregabalin, Gabapentin