Pregabalin

Pregabalin is a GABA analogue and binds with high affinity and selectivity to the α2δ subunit of voltage-sensitive Ca2+ channels and modulates their activity. Pregabalin is an anticonvulsant, anxiolytic analgesic used to treat peripheral neuropathic pain and fibromyalgia.

Pregabalin for chronic pain: does one medication fit all?[Pubmed:25868712]

Curr Med Res Opin. 2015;31(7):1403-11.

BACKGROUND: Pregabalin is frequently prescribed for chronic non-cancer pain. No previous study has examined its off-label use. OBJECTIVES: Our primary aim was to assess the proportion of patients taking Pregabalin for conditions approved by Health Canada ('on-label') and compare their perspectives on its use to those who use Pregabalin for other conditions ('off-label'). METHODS: Patients who have used Pregabalin within the past year were recruited from two registries of chronic non-cancer pain patients treated in tertiary care clinics: the Quebec Pain Registry and the Fibromyalgia Patients Registry. Data on the use of Pregabalin and its perceived benefits were collected from the registries and from completed questionnaires. RESULTS: Out of 4339 screened chronic non-cancer pain patients, 355 (8.18%) met the study selection criteria. Three-quarters of them (268/355) used Pregabalin for pain conditions not approved by Health Canada and were therefore regarded as off-label users. The most prevalent condition for Pregabalin use was lumbar back pain (103/357; 28.85%). There were no significant differences between on- and off-label users in their perceived satisfaction from Pregabalin therapy and its effect on function and quality of life. Among former users, the most prevalent reason for discontinuation was adverse effects, mainly dry mouth and weight gain. CONCLUSIONS: We conclude that despite specific indications for Pregabalin prescription, it is mainly used off-label, notably for low back pain. Nevertheless, off-label users were equally satisfied with its clinical effects. Although formal exploration of the broader analgesic properties of Pregabalin is warranted, treating heterogeneous chronic pain conditions with Pregabalin may be legitimate. LIMITATIONS: The main limitations of the study are patients' low response rate, the recruitment of participants solely from a tertiary pain center and not from the general patient population and a possible recall bias that may have arisen from the retrospective nature of the study.

The antinociceptive effect and mechanisms of action of pregabalin in mice.[Pubmed:25560586]

Pharmacol Rep. 2015 Feb;67(1):129-33.

BACKGROUND: Pregabalin, a potent anticonvulsant agent, is used in treatment-resistant epileptic patients. It is reported that Pregabalin also has analgesic effect in different pain syndromes. However, there is limited data on its antinociceptive mechanisms of action. We aimed to investigate the central and peripheral antinociceptive effects of Pregabalin and the contribution of nitrergic, serotonergic, and opioidergic pathways in mice. METHODS: We used tail flick, tail clip and hot plate tests to investigate the central antinociceptive effects and acetic acid-induced writhing test to assess peripheral antinociceptive effects of Pregabalin (10, 30, 100mg/kg). We also combined Pregabalin (100mg/kg) with, a nonspecific nitric oxide synthase inhibitor l-NAME (100mg/kg), a serotonin receptor antagonist cyproheptadine (50 mug/kg), and an opioid receptor antagonist naloxone (1mg/kg). RESULTS: Pregabalin 30 mg/kg enhanced the percentage of maximal possible effect (% MPE) in tail flick test. Pregabalin 100mg/kg significantly increased % MPE in tail clip and tail flick tests and decreased the number of writhings. Pregabalin made no significant alteration in hot plate test at all doses. The combined use of Pregabalin 100mg/kg with l-NAME, cyproheptadine, and naloxone showed that % MPE was reduced only in the combination of Pregabalin with naloxone and solely in tail clip test while no significant difference was observed in writhing test. CONCLUSIONS: We suggest that Pregabalin (30 and 100mg/kg) presents central spinal but not central supraspinal antinociceptive effect and Pregabalin 100mg/kg shows peripheral antinociceptive effect. The opioidergic pathway seems to mediate the central spinal antinociceptive effect of Pregabalin while nitrergic and serotonergic pathways are not involved.

Evaluation of postoperative pregabalin for attenuation of postoperative shoulder pain after thoracotomy in patients with lung cancer, a preliminary result.[Pubmed:25167976]

Gen Thorac Cardiovasc Surg. 2015 Feb;63(2):99-104.

OBJECTIVE: Thirty-one to 97% of patients who undergo thoracotomy for lung cancer experience ipsilateral shoulder pain, marring the otherwise excellent relief provided by thoracic epidural analgesia. The aim of this study was to test whether the addition of Pregabalin to the treatment for shoulder pain would provide a significant benefit. METHODS: Twenty patients undergoing thoracic surgery for lung cancer were enrolled in the control group between May 2012 and December 2012, and 20 patients were enrolled in the Pregabalin group between January 2013 and July 2013, consecutively. All patients had standard pre- and intraoperative care. Patients received Pregabalin 150 mg po POD 1 and then non-steroidal anti-inflammatory drugs (NSAIDs) po 2 h later (Pregabalin group), or they received only NSAIDs po at exactly the same times (control group). Pain severity was then measured using a 100-mm visual analog scale (VAS) scoring system. RESULTS: The VAS scores indicated that patients in the Pregabalin group had significantly less shoulder pain on postoperative day (POD) 2 than those in the control group (control: 27.9 +/- 28.1 vs. Pregabalin: 11.8 +/- 14.4; p = 0.030). No differences in pain were observed between the two groups on other POD. There were significant differences on only POD 2 in the patients with shoulder pain immediately after surgery. Three of the Pregabalin-treated patients showed mild somnolence. CONCLUSIONS: Postoperative administration of Pregabalin provided significant relief of postoperative shoulder pain during earlier POD after thoracic surgery for lung cancer when received multimodal analgesia in combination with NSAIDs.

The effects of pregabalin on psycho-motor abilities and cognitive processes in mice.[Pubmed:25970965]

Rev Med Chir Soc Med Nat Iasi. 2015 Jan-Mar;119(1):185-92.

UNLABELLED: The purpose of our study was the experimental research on the effects of Pregabalin in two behavioural models in mice. MATERIAL AND METHODS: The experiment was carried out with white Swiss mice treated intraperitoneally as follows: Group I (Control): distilled water 0.1 ml/10 g body weight; Group II (PGB 10): 10 mg/kbw Pregabalin; Group III (PGB 20): 20 mg/kbw Pregabalin. The psychomotor abilities of Pregabalin were tested on a LE-8811 Actimeter device (Panlab), in order to investigate both global motor behaviour and number of escape attempts during an eight-minute interval session. The exploration of memory processes performance was assessed using the Y-maze model, based on the natural tendency of mice to explore new environment. Data were analyzed using SPSS 13.0 for Windows software. The experimental protocols were implemented according the guidelines of "Grigore T. Popa" University Committee for Research and Ethical Issues. RESULTS: The administration of Pregabalin resulted in a dose-dependent reduction of mice horizontal and vertical movements, statistically significant compared to the Control group. The administration of both PGB10 and PGB20 induced no modifications of the spontaneous alternation percent; also, it did not influence the arm entries number compared to Control group in Y-maze test. CONCLUSIONS: The results reflect a significant dose-dependent diminution of number of escape attempts, exploratory and self-maintenance spontaneous behavior after Pregabalin treatment, which could be correlated with an anxiolytic effect. Moreover, the study proved that Pregabalin did not modify the animal cognitive processes performance or influence short-term memory of mice in the Y-maze test.

Impact of pregabalin on acute and persistent postoperative pain: a systematic review and meta-analysis.[Pubmed:25209095]

Br J Anaesth. 2015 Jan;114(1):10-31.

We performed this systematic review to assess the analgesic efficacy of perioperative Pregabalin. Subgroup analyses and meta-regression were performed to assess the impact of individual dose and frequency of Pregabalin administration on analgesic efficacy. We included 55 studies. When all doses and administration regimens were combined, Pregabalin was associated with a significant reduction in pain scores at rest and during movement and opioid consumption at 24 h compared with placebo {mean difference [95% confidence interval (CI)]=-0.38 (-0.57, -0.20), -0.47 (-0.76, -0.18), and -8.27 mg morphine equivalents (-10.08, -6.47), respectively}. Patients receiving Pregabalin had less postoperative nausea and vomiting and pruritus compared with placebo [relative risk (RR) (95% CI)=0.62 (0.48, 0.80) and 0.49 (0.34, 0.70), respectively]. Sedation, dizziness, and visual disturbance were more common with Pregabalin compared with placebo [RR (95% CI)=1.46 (1.08, 1.98), 1.33 (1.07, 1.64), and 3.52 (2.05, 6.04), respectively]. All doses of Pregabalin tested (Pregabalin 100-300 mg between single preoperative dosing regimens and those including additional doses repeated after surgery. Data were insufficient to reach conclusions regarding persistent pain, but limited data available from two studies suggested that Pregabalin might be effective for the reduction of neuropathic pain. In conclusion, this review suggests that Pregabalin improves postoperative analgesia compared with placebo at the expense of increased sedation and visual disturbances.

Evidence that pregabalin reduces neuropathic pain by inhibiting the spinal release of glutamate.[Pubmed:20132471]

J Neurochem. 2010 Apr;113(2):552-61.

Pregabalin is an anti-convulsant that successfully treats many neuropathic pain syndromes, although the mechanism of its anti-hyperalgesic action remains elusive. This study aims to help delineate Pregabalin's anti-hyperalgesic mechanisms. We assessed the effectiveness of Pregabalin at decreasing mechanical and cold hypersensitivity induced in a rat model of neuropathic pain. Thus, we compared the effectiveness of pre- or post-treatment with systemic or intrathecal (i.t.) Pregabalin at reducing the development and maintenance of the neuropathic pain symptoms. Pregabalin successfully decreased mechanical and cold hypersensitivity, as a pre-treatment, but was less effective at suppressing cold hypersensitivity when administered as a post-treatment. Furthermore, both i.t. and systemic administration of Pregabalin were effective in reducing the behavioral hypersensitivity, with the exception of systemic post-treatment on cold hypersensitivity. We also examined Pregabalin's effects at inhibiting hind paw formalin-induced nociception in naive rats and formalin-induced release of excitatory amino acids in the spinal cord dorsal horn (SCDH) both in naive rats and in rats with neuropathic pain. Pregabalin dose-dependently reduced nociceptive scores in the formalin test. We also present the first evidence that Pregabalin reduces the formalin-induced release of glutamate in SCDH. Furthermore, i.t. Pregabalin reduces the enhanced noxious stimulus-induced spinal release of glutamate seen in neuropathic rats. These data suggest that Pregabalin reduces neuropathic pain symptoms by inhibiting the release of glutamate in the SCDH.

Pregabalin may represent a novel class of anxiolytic agents with a broad spectrum of activity.[Pubmed:11156553]

Br J Pharmacol. 2001 Jan;132(1):1-4.

The present study examines the effect of Pregabalin (previously S-Isobutylgaba and CI-1008) in two distinct rat models of anxiety. Pregabalin binds with high affinity and selectivity to the alpha(2)delta subunit of voltage dependent calcium channels (VDCC). Its corresponding R-enantiomer (R-isobutylgaba) is approximately 10 fold weaker. Pregabalin dose-dependently induced anxiolytic-like effects in both the rat conflict test and elevated X-maze with respective minimum effective doses (MED) of 3 and 10 mg kg(-1). In contrast, R-isobutylgaba only showed activity at the highest dose of 100 mg kg(-1) in the conflict test. These data indicate that Pregabalin may possess clinical utility as a novel anxiolytic agent and demonstrates the importance of the alpha(2)delta subunit of VDCC in the mediation of anxiety related behaviours.