Efficacy and safety of pregabalin for treating painful diabetic peripheral neuropathy: a meta-analysis

Pregabalin in patients with post-traumatic peripheral neuropathic pain: A meta-analysis of randomized controlled trials

OBJECTIVE

The aim of the study was to investigate the safety and efficacy of pregabalin versus placebo in post-traumatic peripheral neuropathic pain (PTNP).

METHODS

PubMed, Cochrane Library, Web of Science, and Google Scholar were searched for relevant evidence up to January 2022. The Cochran tool was used to assess the quality of randomized clinical trials (RCTs). Data analysis was performed using Comprehensive Meta-Analysis software.

RESULTS

Three RCTs involving 821 patients were included in the meta-analysis. A significant difference was observed between pregabalin and placebo in terms of the pain score (the standardized mean difference [SMD] = -0.14, 95% CI: 0.28 to -0.006, p = 0.04) and sleep interference (MD = -0.25, 95% CI: -0.39 to -0.11, p = 0.00). There was also a significant difference between pregabalin and placebo regarding somnolence (risk ratio [RR] = 2.78; 95% CI: 1.64-4.71, p = 0.00), dizziness (RR = 4.13; 95% CI: 2.71-6.28, p = 0.00), and disturbance in attention (RR: 2.97; 95% CI: 1.02-8.65, p = 0.04). However, no significant difference was observed between pregabalin and placebo in terms of headache (RR = 1.20; 95% CI: 0.70-2.06, p = 0.50), fatigue (RR = 1.42; 95% CI: 0.82-2.47, p = 0.20), nausea (RR = 1.52; 95% CI: 0.88-2.62, p = 0.13), constipation (RR = 1.84; 95% CI: 0.78-4.29, p = 0.15), and discontinuation (RR = 1.52; 95% CI: 0.45-5.06, p = 0.49).

CONCLUSION

Compared with placebo, pregabalin showed better efficacy in reducing PTNP and improving sleep interference. However, it was associated with higher adverse events. Further RCTs are needed to confirm these findings.

Efficacy and safety of Mudan granules for painful diabetic peripheral neuropathy: A protocol for a double-blind randomized controlled trial

BACKGROUND

As one of the most challenging complications in the management of diabetes mellitus, painful diabetic peripheral neuropathy (PDPN) is accompanied by various clinical manifestations, including numbness, burning, coldness, and other sensory abnormalities in the extremities. Meanwhile, PDPN seriously affects the life quality of patients and causes great pain. Western medicine mostly provides symptomatic treatments, such as antioxidants, aldose reductase inhibitors, nerve nutrition, microcirculation improvement, and analgesic drugs on the basis of blood sugar control. Although certain efficacy has been achieved, the problem has not been solved at root. Mudan granules have some advantages in the treatment of PDPN, but there is insufficient high-quality clinical studies to verify this. Therefore, the purpose of this study was to evaluate the efficacy and safety of Mudan granules in treating PDPN.

METHODS

A randomized, double-blind, placebo, and parallel-controlled trial design was used to study the efficacy and safety of Mudan granules in the treatment of PDPN. In this study, 93 patients with painful diabetic neuropathy were recruited and randomly divided into a treatment group and a placebo group based on 1:1. The treatment group was given Mudan granules and the control group accepted placebo treatment, and the basic treatment was performed according to the recommended guidelines. During the treatment period, the patients' visual analog scores, clinical efficacy, Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) scores, nerve conduction velocity, and drug-induced adverse reactions were observed at baseline after 8 and 10 weeks.

DISCUSSION

This study will evaluate the efficacy and safety of Mudan granules in treating PDPN. The experimental results will provide evidence support to treat PDPN with Mudan granules.

TRIAL REGISTRATION

DOI 10.17605/OSF.IO/5CE32.

Diabetic Peripheral Neuropathy

Diabetic painless and painful peripheral neuropathy remains the most frequent complication of diabetes mellitus, but the pathophysiology remains undescribed, there are no robust clinical endpoints and no efficient treatment exists. This hampers good clinical practice, fruitful clinical research and successful pharmacological trials, necessary for the development of early detection, prevention and treatment. This chapter supplies an update on background and treatment of diabetic peripheral neuropathy. Goals and perspectives for future clinical and scientific approaches are also described.

Pharmacological interactions between intrathecal pregabalin plus tianeptine or clopidogrel in a rat model of neuropathic pain

Background

There is still unmet need in treating neuropathic pain and increasing awareness regarding the use of drug combinations to increase the effectiveness of treatment and reduce adverse effects in patients with neuropathic pain.

Methods

This study was performed to determine the individual and combined effects of pregabalin, tianeptine, and clopidogrel in a rat model of neuropathic pain. The model was created by ligation of the L5-L6 spinal nerve in male Sprague-Dawley rats; mechanical allodynia was confirmed using von Frey filaments. Drugs were administered to the intrathecal space and mechanical allodynia was assessed; drug interactions were estimated by isobolographic or fixed-dose analyses.

Results

Intrathecal pregabalin and tianeptine increased the mechanical withdrawal threshold in a dose-dependent manner, but intrathecal clopidogrel had little effect on the mechanical withdrawal threshold. An additive effect was noted between pregabalin and tianeptine, but not between pregabalin and clopidogrel.

Conclusions

These findings suggest that intrathecal coadministration of pregabalin and tianeptine effectively attenuated mechanical allodynia in the rat model of neuropathic pain. Thus, pregabalin plus tianeptine may be a valid option to enhance the efficacy of neuropathic pain treatment.

Different Drugs for the Treatment of Painful Diabetic Peripheral Neuropathy: A Meta-Analysis

Objective: To systematically evaluate the effects of different drugs for the treatment of painful diabetic peripheral neuropathy.

Methods: All literature from PubMed, Embase, and Cochrane Central Register of Controlled Trials published over the past 12 years (from January 1, 2008 to June 1, 2020) was searched, and two reviewers independently assessed study eligibility, continuous data extraction, independent assessment of bias risk, and graded strength of evidence. The pain score was used as the main result, and 30 and 50% pain reduction and adverse events were used as secondary results.

Results: A total of 37 studies were included. Pregabalin, duloxetine, tapentadol, lacosamide, mirogabalin, and capsaicin were all more effective than placebo in alleviating the pain associated with diabetic peripheral neuropathy, while ABT-894 and gabapentin showed no significant effect. In addition, the efficacy of buprenorphine, tanezumab, fulranumab and others could not be concluded due to insufficient studies.

Conclusion: Pregabalin and duloxetine showed good therapeutic effects on painful DPN, but adverse events were also significant. The analgesic effects of ABT-894 and gabapentin need to be further studied with longer and larger RCTs. As an opioid drug, tapentadol has a good analgesic effect, but due to its addiction, it needs to be very cautious in clinical use. Although lacosamide, mirogabalin, and capsaicin are more effective than placebo, the therapeutic effect is weaker than pregabalin. For the results of our meta-analysis, long-term studies are still needed to verify their efficacy and safety in the future.

Systematic Review Registration: PROSPERO, identifier: CRD42020197397.

Diabetic Peripheral Neuropathy: Diagnosis and Treatment

BACKGROUND

Diabetic peripheral neuropathy (DPN) is traditionally divided into large and small fibre neuropathy (SFN). Damage to the large fibres can be detected using nerve conduction studies (NCS) and often results in a significant reduction in sensitivity and loss of protective sensation, while damage to the small fibres is hard to reliably detect and can be either asymptomatic, associated with insensitivity to noxious stimuli, or often manifests itself as intractable neuropathic pain.

OBJECTIVE

To describe the recent advances in both detection, grading, and treatment of DPN as well as the accompanying neuropathic pain.

METHODS

A review of relevant, peer-reviewed, English literature from MEDLINE, EMBASE and Cochrane Library between January 1st 1967 and January 1st 2020 was used.

RESULTS

We identified more than three hundred studies on methods for detecting and grading DPN, and more than eighty randomised-controlled trials for treating painful diabetic neuropathy.

CONCLUSION

NCS remains the method of choice for detecting LFN in people with diabetes, while a gold standard for the detection of SFN is yet to be internationally accepted. In the recent years, several methods with huge potential for detecting and grading this condition have become available including skin biopsies and corneal confocal microscopy, which in the future could represent reliable endpoints for clinical studies. While several newer methods for detecting SFN have been developed, no new drugs have been accepted for treating neuropathic pain in people with diabetes. Tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors and anticonvulsants remain first line treatment, while newer agents targeting the proposed pathophysiology of DPN are being developed.

Complex encephalopathy arising from the combination of opioids and gabapentin

The interactions between opioids and gabapentin are more clinically relevant than ever. Prescriptions dispensed for gabapentin increased from 39 million in 2012 to 64 million in 2018 in the USA and are ever increasing. Authors present a challenging case of these interactions. A 58-year-old man presented to the emergency department with acute respiratory failure and altered mental status. He was on high dose opioids and gabapentin as prescription medications. Despite full intensive care support and resolution of his respiratory failure with non-invasive positive pressure ventilation, the patient did not regain consciousness. After ruling out other causes, the diagnosis of gabapentin withdrawal was considered. Gabapentin was administered by a nasogastric tube that quickly resulted in a reversal of his symptoms. We concluded that severe gabapentin withdrawal should be considered in patients on higher doses of gabapentin when it is stopped abruptly. In such patients, gabapentin should be replaced. As most patients are unable to swallow in this situation and intravenous formulation is not available, nasogastric tube can be used for replacement.

Complex encephalopathy arising from the combination of opioids and gabapentin

The interactions between opioids and gabapentin are more clinically relevant than ever. Prescriptions dispensed for gabapentin increased from 39 million in 2012 to 64 million in 2018 in the USA and are ever increasing. Authors present a challenging case of these interactions. A 58-year-old man presented to the emergency department with acute respiratory failure and altered mental status. He was on high dose opioids and gabapentin as prescription medications. Despite full intensive care support and resolution of his respiratory failure with non-invasive positive pressure ventilation, the patient did not regained consciousness. After ruling out other causes, the diagnosis of gabapentin withdrawal was considered. Gabapentin was administered by a nasogastric tube that quickly resulted in a reversal of his symptoms. We concluded that severe gabapentin withdrawal should be considered in patients on higher doses of gabapentin when it is stopped abruptly. In such patients, gabapentin should be replaced. As most patients are unable to swallow in this situation and intravenous formulation is not available, nasogastric tube can be used for replacement.

Pregabalin in the treatment of postmastectomy chronic pain: Results of an open label, single-arm clinical study

Postmastectomy chronic pain (PMCP) is one of the important survivorship issues faced by breast cancer patients. It is a chronic pain which persists for more than 3 months after mastectomy or quadrantectomy and is considered to be neuropathic in nature. An open label, single-arm, prospective study was conducted to evaluate the efficacy of Pregabalin in relieving clinically significant PMCP (pain score ≥3 on visual analogue scale). Pregabalin brought about significant reductions in pain (visual analogue scale [VAS] Scores; baseline 5.50 ± 1.197, end of 1 month 2.40 ± 1.430, end of 2 months 2.10 ± 1.370) and significant improvement in quality of life.

Randomised clinical trial: pregabalin vs placebo for irritable bowel syndrome

BACKGROUND

Pregabalin is a calcium channel α2δ ligand that modifies visceral hypersensitivity in IBS patients. Clinical data for pregabalin in IBS are lacking.

AIM

To test the efficacy of pregabalin on gastrointestinal symptoms in IBS patients.

METHODS

A double-blind, placebo-controlled trial was performed. Adults meeting IBS Rome III criteria with ≥3 pain attacks per month were randomised to pregabalin 225 mg vs placebo twice daily for 12 weeks. Questionnaires were completed weekly. The primary endpoint was average pain Bowel Symptom Scale (BSS) scores weeks 9-12. An intention-to-treat analysis of covariance evaluated treatment effects on quantitative endpoints, adjusting for age and gender. Adequate relief and change in pain score were assessed using a chi-squared test.

RESULTS

Eighty-five patients were recruited and randomised. Sample characteristics include: mean age 39.4 (SD = 14.6); 73 (86%) female; 37 (44%) IBS-D, 29 (35%) IBS-M, 18 (21%) IBS-C. The pregabalin arm had lower average pain-BSS scores weeks 9-12 (25 vs 42, P = 0.008). Compared with placebo, the overall IBS BSS severity score was lower in the pregabalin arm (26 vs 42, P = 0.009). Differences were observed for the diarrhoea-BSS and bloating-BSS scores (P = 0.049 and 0.016, respectively). No differences between groups were seen for constipation-BSS scores. Adequate relief was not different between the two arms (46% vs 36%, P = 0.35). 63% pregabalin vs 45% placebo had a change in pain score ≥30 at week 12 from baseline (P = 0.10). Post-treatment IBS-QoL scores did not differ between groups.

CONCLUSION

This trial suggests that pregabalin may be beneficial for IBS abdominal pain, bloating and diarrhoea.

Pregabalin in the Management of Painful Diabetic Neuropathy: A Narrative Review

Pregabalin is a first-line treatment in all major international guidelines on the management of painful diabetic neuropathy (pDPN). Treatment with pregabalin leads to a clinically meaningful improvement in pain scores, offers consistent relief of pain and has an acceptable tolerance level. Despite its efficacy in relieving neuropathic pain, more robust methods and comprehensive studies are required to evaluate its effects in relation to co-morbid anxiety and sleep interference in pDPN. The sustained benefits of modulating pain have prompted further exploration of other potential target sites and the development of alternative GABAergic agents such as mirogabalin. This review evaluates the role of pregabalin in the management of pDPN as well as its potential adverse effects, such as somnolence and dizziness, which can lead to withdrawal in ~ 30% of long-term use. Recent concern about misuse and an increase in deaths linked to its use has led to demands for reclassification of pregabalin as a class C controlled substance in the UK. We believe these demands need to be tempered in relation to the difficulties it would create for repeat prescriptions for the many millions of patients with pDPN for whom pregabalin provides benefit.Plain Language Summary: Plain language summary available for this article.

Benefits and harms of pregabalin in the management of neuropathic pain: a rapid review and meta-analysis of randomised clinical trials

OBJECTIVE

To assess the benefits and harms of pregabalin in the management of neuropathic pain.

DESIGN

Rapid review and meta-analysis of phase III, randomised, placebo-controlled trials.

PARTICIPANTS

Adults aged 18 years and above with neuropathic pain defined according to the International Association for the Study of Pain criteria.

INTERVENTIONS

Pregabalin or placebo.

PRIMARY AND SECONDARY OUTCOME MEASURES

Our primary outcomes were pain (as measured using validated scales) and adverse events. Our secondary outcomes were sleep disturbance, quality of life, Patient Global Impression of Change, Clinician Global Impression scale, anxiety and depression scores, overall discontinuations and discontinuations because of adverse events.

RESULTS

We included 28 trials comprising 6087 participants. The neuropathic pain conditions studied were diabetic peripheral neuropathy, postherpetic neuralgia, herpes zoster, sciatica (radicular pain), poststroke pain and spinal cord injury-related pain. Patients who took pregabalin reported significant reductions in pain (numerical rating scale (NRS)) compared with placebo (standardised mean difference (SMD) -0.49 (95% CI -0.66 to -0.32, p<0.00001), very low quality evidence). Pregabalin significantly reduced sleep interference scores (NRS) compared with placebo (SMD -0.38 (95% CI -0.50 to -0.26, p<0.00001), moderate quality evidence. Pregabalin significantly increased the risk of adverse events compared with placebo (RR 1.33 (95% CI 1.23 to 1.44, p<0.00001, low quality evidence)). The risks of experiencing weight gain, somnolence, dizziness, peripheral oedema, fatigue, visual disturbances, ataxia, non-peripheral oedema, vertigo and euphoria were significantly increased with pregabalin. Pregabalin was significantly more likely than placebo to lead to discontinuation of the drug because of adverse events (RR 1.91 (95% CI 1.54 to 2.37, p<0.00001), low quality evidence).

CONCLUSION

Pregabalin has beneficial effects on some symptoms of neuropathic pain. However, its use significantly increases the risk of a number of adverse events and discontinuation due to adverse events. The quality of the evidence from journal publications is low.

Efficacy and safety of pregabalin for painful diabetic peripheral neuropathy in a population of Chinese patients: A randomized placebo-controlled trial

BACKGROUND

Limited information exists regarding the efficacy of pregabalin in Chinese patients with painful diabetic peripheral neuropathy (pDPN).

METHODS

An 11-week double-blind placebo-controlled trial was performed in Chinese pDPN patients randomized (1 : 1) to 300 mg/day pregabalin or placebo. The primary outcome was change from baseline to endpoint in mean pain score (MPS; 0, no pain; 10, worst possible pain; using the mean of the last seven daily pain scores). Secondary outcomes included weekly MPS and responder status (MPS reduced by ≥30% or ≥50% vs baseline). Subgroup analysis assessed patients with severe (≥7) baseline MPS. Adverse events (AEs) were reported.

RESULTS

In all, 620 patients were randomized (pregabalin, n = 313; placebo, n = 307). Improvement in MPS with pregabalin versus placebo was not significant (P = 0.0559). Post hoc sensitivity analyses, excluding one patient/site due to Good Clinical Practice (GCP) non-compliance, showed pregabalin significantly improved MPS when excluding the patient (P = 0.0448) or site (P = 0.0142). Pregabalin significantly improved weekly MPS (P = 0.0164) and ≥50% responders at endpoint (P = 0.0384). Improvement in proportion of ≥30% responders, impression of change, pain intensity, and sleep did not differ significantly between the treatment groups. In the severe pDPN subpopulation, pregabalin significantly improved MPS versus placebo (P = 0.0040). The most commonly reported AE was dizziness (9.6% vs 3.9% with placebo).

CONCLUSIONS

Pregabalin did not significantly improve the primary measure of pain in the trial. Significant reductions in MPS were observed when excluding the GCP non-compliant patient/site and in the severe pDPN subpopulation. Pregabalin was well tolerated in Chinese pDPN patients.

The Quest for more Research on Painful Diabetic Neuropathy

A 62-year-old diabetologist diagnosed himself to have diabetes type-2, with an HbA1c of 9.5. Five months after lifestyle intervention and a multi-drug approach, HbA1c was 6.3, systolic blood pressure was below 135mmHg and BMI reduced to 27. But he suffered from severe painful diabetic neuropathy. Therefore he decided to visit his friend, a famous neuroscientist at an even more famous university. He asked him several plain questions: 1. What is the natural course of painful diabetic neuropathy? 2. Why do I have, despite almost normalizing HbA1c, more problems than before? 3. Are you sure my problems are due to diabetes or should we do a nerve biopsy? 4. Are there imaging techniques helpful for the diagnosis of this diabetic complication, starting in the distal nerve endings of the foot and slowly moving ahead? 5. Can you suggest any drug, specific and effective, for relieving painful diabetic neuropathy? This review will use the experts' answers to the questions of the diabetologist, not only to give a summary of the current knowledge, but even more to highlight areas of research needed for improving the fate of patients with painful diabetic neuropathy. Based on the unknowns, which exceed the knowns in diabetic neuropathy, a quest for more public support of research is made.

Capsaicin 8% Patch Versus Oral Neuropathic Pain Medications for the Treatment of Painful Diabetic Peripheral Neuropathy: A Systematic Literature Review and Network Meta-analysis

PURPOSE

A network meta-analysis (NMA) was performed, aiming to assess the relative efficacy and tolerability of the capsaicin 179-mg (8% weight for weight) cutaneous patch (capsaicin 8% patch) compared with oral, centrally acting agents (ie, pregabalin, gabapentin, duloxetine, amitriptyline) in patients with painful diabetic peripheral neuropathy (PDPN).

METHODS

A systematic search of EMBASE/MEDLINE, Cochrane Library, and the National Health Service Centre for Reviews and Dissemination Database of Abstracts of Reviews of Effects was conducted to identify all randomized controlled trials. Data from eligible studies according to predefined inclusion and exclusion criteria were extracted, and analyses were based on aggregate-level data. Efficacy outcomes were the proportions of patients with ≥30% and ≥50% reductions in pain, and tolerability outcomes were somnolence, dizziness, nausea, diarrhea, constipation, headache, fatigue, insomnia, and rate of discontinuation due to adverse events (AEs). Data were analyzed by using a Bayesian NMA. Fixed and random effects models were estimated. Relative treatment effect was presented as odds ratios (ORs) with 95% CIs. Sources of heterogeneity were assessed.

FINDINGS

The NMA included 25 randomized controlled trials. For ≥30% pain reduction, the capsaicin 8% patch was significantly more effective than placebo (OR, 2.28 [95% CI, 1.19-4.03]), exhibited a numerical advantage compared with pregabalin (OR, 1.83 [95% CI, 0.91-3.34]) and gabapentin (OR, 1.66 [95% CI, 0.74-3.23]), and had similar efficacy compared with duloxetine (OR, 0.99 [95% CI, 0.5-1.79]). The evidence available was not sufficient to assess the relative efficacy of amitriptyline. In the NMA for tolerability, the capsaicin 8% patch was only included for headache because the incidence was 0% for the other outcomes. Oral, centrally acting agents had a significantly elevated risk compared with placebo for somnolence (pregabalin, gabapentin, duloxetine, and amitriptyline), dizziness (pregabalin, gabapentin, duloxetine, and amitriptyline), nausea (duloxetine), diarrhea (duloxetine), fatigue (duloxetine), and discontinuation because of AEs (pregabalin, gabapentin, and duloxetine). Compared with pregabalin and gabapentin, duloxetine had a significantly lower risk of dizziness but a significantly higher risk of nausea.

IMPLICATIONS

This NMA suggests that the efficacy observed with the capsaicin 8% patch is similar to that observed with oral agents (ie, pregabalin, duloxetine, gabapentin) in patients with PDPN. The oral agents were associated with a significantly elevated risk of somnolence, dizziness, fatigue, and discontinuation because of AEs compared with placebo. The capsaicin 8% patch was as effective as oral centrally acting agents in these patients with PDPN but offers systemic tolerability benefits.

Efficacy and Safety of Pregabalin for the Treatment of Neuropathic Pain in Patients Undergoing Hemodialysis

OBJECTIVE

Pregabalin is a gamma aminobutyric acid derivative administered for neuropathic pain. It binds to α2δ subunits of voltage-dependent calcium channels, and inhibits calcium inflow of synapses and the release of excitatory neurotransmitters. This study investigated the efficacy and safety of pregabalin in patients with peripheral neuropathic pain undergoing maintenance hemodialysis.

METHODS

This study was a prospective, open-label, single-arm, multi-center trial. Patients were treated with an initial dose of pregabalin at 25 mg; this was then increased up to a maximum of 150 mg depending on the patient during a 12-week study period. Visual Analog Scale, Eight-Item Short Form Health Survey (SF-8), and laboratory data were collected at baseline and the end of the study.

RESULTS

A total of 45 patients with peripheral neuropathic pain were included, of whom 35 patients were analyzed. The final mean dose of pregabalin was 50.7 mg daily. Mean Visual Analog Scale scores significantly decreased from 52.4 mm at baseline to 34.1 mm at the end of the study (p < 0.0001). Scores for all eight categories of the SF-8 significantly increased compared with baseline (p < 0.05). Both physical and mental component summary scores of the SF-8 also significantly increased (p < 0.05). Ten patients were withdrawn from the study because of drowsiness, dizziness, and invalidity; however, no serious adverse drug reactions were recorded.

CONCLUSIONS

If adverse effects are carefully monitored and the administered dosage prudently determined, pregabalin can be an effective treatment for peripheral neuropathic pain in patients undergoing hemodialysis.

TRIAL REGISTRATION

UMIN000023117.

The effect of pregabalin on acute postoperative pain in patients undergoing total knee arthroplasty: A meta-analysis

OBJECTIVE

The purpose of this systematic review and meta-analysis of randomised controlled trials (RCTs) was to evaluate the effect of pain control of pregabalin versus placebo after a total knee arthroplasty (TKA).

METHODS

The electronic databases: Medline, Embase, PubMed, CENTRAL (Cochrane Controlled Trials Register), Web of Science and Google were searched from inception to February 2016. This systematic review and meta-analysis were performed according to the PRISMA statement criteria. The primary endpoint was the visual analogue scale (VAS) after a TKA with rest or mobilization at 24 h and 48 h, which represents the effect of pain control after TKA. The cumulative morphine consumption is also assessed to the morphine-sparing effect. The complications of nausea, vomiting, dizziness and sedation were also compiled to assess the safety of pregabalin. Software Stata 12.0 was used for the meta-analysis. After testing for publication bias and heterogeneity across studies, data were aggregated for random-effects modelling when necessary.

RESULTS

Six clinical trials with 769 patients were used for the meta-analysis. The meta-analysis indicated that pregabalin can decrease the VAS with rest at 24 h (MD = -8.14; 95% CI -12.57 to -3.71; P < 0.001) and 48 h (MD = -7.34; 95% CI -11.65 to -3.02; P < 0.001). Pregabalin can decrease the VAS with mobilization at 24 h (MD = -6.56; 95% CI -10.45 to -2.66; P = 0.001) and 48 h (MD = -9.62; 95% CI -12.80 to -6.44; P < 0.001). The results indicated that perioperative pregabalin can decrease the cumulative morphine consumption at 24 h (SMD = -0.97; 95% CI -1.17 to -0.78; P < 0.001) and 48 h (MD = -2.23; 95% CI -2.48 to -1.97; P < 0.001). Moreover, pregabalin can decrease the occurrence of nausea and vomiting but increase the occurrence of dizziness and sedation.

CONCLUSION

Based on the current meta-analysis, pregabalin has an analgesic and opioid-sparing effect in acute postoperative pain management without increasing the rate of nausea, vomiting.

Alpha2delta ligands, gabapentin, pregabalin and mirogabalin: a review of their clinical pharmacology and therapeutic use

INTRODUCTION

The first two alpha₂delta ligands - gabapentin (GBP) and pregabalin (PGB) - were initially synthesized as antiepileptics; however, they were later also found to be useful for the treatment of additional conditions. Areas covered: Relevant publications describing potential underlying mechanisms, clinical pharmacokinetics/pharmacokinetics, and clinical efficacy and safety of these drugs in various disease conditions were searched in PubMed and Scopus and included in this review. Expert commentary: GBP and PGB are effective for the treatment neuropathic pain, fibromyalgia and epilepsy; in addition, they may be useful for the reduction of postoperative pain. PGB is also effective for the treatment of generalized anxiety disorder and GBP for the treatment of restless legs syndrome. GBP may be considered a treatment option for pain associated with Guillain-Barré Syndrome and phantom limb and for the management of uremic pruritus. Mirogabalin (MGB), recently developed, is being investigated for the treatment of peripheral neuropathic pain and fibromyalgia, showing promising results in patients with diabetic peripheral neuropathy. Their most frequent adverse reactions are of neuropsychiatric nature and include fatigue, dizziness, sedation, somnolence, and ataxia; peripheral edema and weight gain are also frequently described. Pharmacokinetic interactions are scarce; however, pharmacodynamic interactions have been described in association with drugs with CNS-depressant effects.

Effect of pregabalin on contextual memory deficits and inflammatory state-related protein expression in streptozotocin-induced diabetic mice

Diabetes mellitus is a metabolic disease characterized by hyperglycemia due to defects in insulin secretion or its action. Complications from long-term diabetes consist of numerous biochemical, molecular, and functional tissue alterations, including inflammation, oxidative stress, and neuropathic pain. There is also a link between diabetes mellitus and vascular dementia or Alzheimer’s disease. Hence, it is important to treat diabetic complications using drugs which do not aggravate symptoms induced by the disease itself. Pregabalin is widely used for the treatment of diabetic neuropathic pain, but little is known about its impact on cognition or inflammation-related proteins in diabetic patients. Thus, this study aimed to evaluate the effect of intraperitoneal (ip) pregabalin on contextual memory and the expression of inflammatory state-related proteins in the brains of diabetic, streptozotocin (STZ)-treated mice. STZ (200 mg/kg, ip) was used to induce diabetes mellitus. To assess the impact of pregabalin (10 mg/kg) on contextual memory, a passive avoidance task was applied. Locomotor and exploratory activities in pregabalin-treated diabetic mice were assessed by using activity cages. Using Western blot analysis, the expression of cyclooxygenase-2 (COX-2), cytosolic prostaglandin E synthase (cPGES), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), nuclear factor-ĸB (NF-ĸB) p50 and p65, aryl hydrocarbon receptor (AhR), as well as glucose transporter type-4 (GLUT4) was assessed in mouse brains after pregabalin treatment. Pregabalin did not aggravate STZ-induced learning deficits in vivo or influence animals’ locomotor activity. We observed significantly lower expression of COX-2, cPGES, and NF-κB p50 subunit, and higher expression of AhR and Nrf2 in the brains of pregabalin-treated mice in comparison to STZ-treated controls, which suggested immunomodulatory and anti-inflammatory effects of pregabalin. Antioxidant properties of pregabalin in the brains of diabetic animals were also demonstrated. Pregabalin does not potentiate STZ-induced cognitive decline, and it has antioxidant, immunomodulatory, and anti-inflammatory properties in mice. These results confirm the validity of its use in diabetic patients.

Graphical abstract

Randomized Double-Blind Trial of Pregabalin Versus Placebo in Conjunction With Palliative Radiotherapy for Cancer-Induced Bone Pain

PURPOSE

Cancer-induced bone pain (CIBP) affects one third of patients with cancer. Radiotherapy remains the gold-standard treatment; however, laboratory and clinical work suggest that pregabalin may be useful in treating CIBP. The aim of this study was to examine pregabalin in patients with CIBP receiving radiotherapy.

PATIENTS AND METHODS

A multicenter, double-blind randomized trial of pregabalin versus placebo was conducted. Eligible patients were age ≥ 18 years, had radiologically proven bone metastases, were scheduled to receive radiotherapy, and had pain scores ≥ 4 of 10 (on 0-to-10 numeric rating scale). Before radiotherapy, baseline assessments were completed, followed by random assignment. Doses of pregabalin and placebo were increased over 4 weeks. The primary end point was treatment response, defined as a reduction of ≥ 2 points in worst pain by week 4, accompanied by a stable or reduced opioid dose, compared with baseline. Secondary end points assessed average pain, interference of pain with activity, breakthrough pain, mood, quality of life, and adverse events.

RESULTS

A total of 233 patients were randomly assigned: 117 to placebo and 116 to pregabalin. The most common cancers were prostate (n = 88; 38%), breast (n = 77; 33%), and lung (n = 42; 18%). In the pregabalin arm, 45 patients (38.8%) achieved the primary end point, compared with 47 (40.2%) in the placebo arm (adjusted odds ratio, 1.07; 95% CI, 0.63 to 1.81; P = .816). There were no statistically significant differences in average pain, pain interference, or quality of life between arms. There were differences in mood (P = .031) and breakthrough pain duration (P = .037) between arms. Outcomes were compared at 4 weeks.

CONCLUSION

Our findings do not support the role of pregabalin in patients with CIBP receiving radiotherapy. The role of pregabalin in CIBP with a clinical neuropathic pain component is unknown.

Opioid analgesics increase incidence of somnolence and dizziness as adverse effects of pregabalin: a retrospective study

BACKGROUND

Pregabalin, a gabapentinoid, is an adjuvant analgesic for treatment of neuropathic pain, but it has serious adverse effects such as somnolence and dizziness, particularly in elderly patients. Although decreased renal function is considered to the contributing factor for high frequency of these adverse effects in elder patients, only a few systematic clinical investigations, especially for hospitalized patients, have been performed on factors that might affect the incidence of its adverse effects. In this study, we performed a retrospective study on the effect of concomitant drugs on induction of somnolence and dizziness as adverse effects of pregabalin in hospitalized patients.

METHODS

The subjects were all pregabalin-administered patients in Shiga University of Medical Science Hospital from September 2010 to September 2012, and the subject number was 195. Multivariate logistic regression analysis was performed to determine predictors of the adverse effects, creatinine clearance, duration of pregabalin therapy, initial and maintenance doses of pregabalin, and concomitant drugs, including hypoglycemic drugs, anti-hypertensive ones, non-steroidal anti-inflammatory ones, opioids and central nervous system depressants, being used as independent variables.

RESULTS

The median initial doses of pregabalin in each renal function group were the same with the case of the defined dose. Although renal function is a well-known factor for prediction of development of adverse effects of pregabalin, we did not detect significant contribution of it. Alternatively, it was demonstrated that concomitant administration of opioids was the significant factor of the incidence of somnolence and dizziness. The first onset date of the adverse effects was frequently detected in the early days of the pregabalin therapy.

CONCLUSIONS

The fine tuning of pregabalin dosage schedule based on the renal function appeared to be critical for prevention of development of its adverse effects. Adverse effects tended to develop in the initial phase of pregabalin therapy. Concomitant administration of opioids with pregabalin has the potential to increase the incidence of adverse effects, and thus much more careful attention has to be paid especially in those situations.