Patterns of gabapentinoid use among long-term opioid users.

OBJECTIVE: Understanding the clinical and demographic profile of patients on gabapentinoids can highlight areas of prescribing disparities, inform clinical practice, and guide future research to optimize effectiveness and safety of gabapentinoids for pain management. We used a national sample of Medicare beneficiaries to examine trends, patterns, and patient-level predictors of gabapentinoid use among long-term opioid users. METHODS: Using a national Medicare sample between 2014 and 2020, we examined factors associated with gabapentinoid use among long-term opioid users. We included Medicare eligible long-term opioid users with no prior gabapentinoid use. The primary outcome was gabapentinoid use after the long-term opioid use episode. Logistic regression was used to test the association with gabapentinoid use for year, age, sex, race/ethnicity, region, Medicare entitlement, low-income status, frailty, pain locations, anxiety, depression, opioid use disorder, and opioid morphine milligrams equivalent. RESULTS: Gabapentinoid use among long-term opioid users increased from 12.6% in 2014 to 16.8% in 2019 (p < .0001). Factors associated with increased gabapentinoid use were Hispanic ethnicity, back pain, nerve pain, and moderate or high opioid usage. Factors associated with decreased gabapentinoid use were older age and Medicare entitlement due to old age. CONCLUSIONS: Variation of gabapentinoid use by socio-demographics and insurance status indicates opportunities to improve pain management and a need for shared therapeutic decision making informed by discussion between pain patients and providers regarding safety and effectiveness of pain therapies. Our findings underscore the need for future research into the comparative effectiveness and safety of gabapentinoids for non-cancer chronic pain in various subpopulations.

[Neuropathy in pruritus medicine : Recommended diagnostics and therapy]. / Neuropathie in der Pruritusmedizin : Empfohlene Diagnostik und Therapie.

Chronic itch is a frequent and debilitating condition that greatly affects the quality of life of those affected. In a subset of patients, damage to the peripheral or central nervous system constitutes the cause of the itch. Small-fiber neuropathy, nerve compression syndromes, post-herpetic neuralgia, scars and burns are possible conditions affecting the peripheral nervous system potentially causing itch, whereas space-occupying lesions affecting the spinal cord and stroke are examples of conditions that may induce central itch. Neuropathic itch starts on normal appearing skin, is often accompanied by pain sensations and other dysesthesias, and usually relieved by local cold application. Its distribution depends on the affected site of the somatosensory system. A comprehensive medical history is paramount to reach the diagnosis, while complementary diagnostics with skin biopsies for the investigation of cutaneous neuromorphological alterations or medical imaging to rule out nerve impingement may be advised in selected cases. Topical agents such as capsaicin or local anesthetics as well as systemic drugs such as gabapentinoids, antidepressants and opioid receptor modulators are used in the treatment of neuropathic itch. This review article provides an overview of the clinical features, underlying causes, diagnostic workup and therapeutic approach in neuropathic itch.

Risk of drug-related death associated with co-prescribing of gabapentinoids and Z-drugs among people receiving opioid-agonist treatment: A national retrospective cohort study.

BACKGROUND: Prescribing of gabapentinoids and Z-drug-hypnotics has increased in the population and among people receiving opioid-agonist treatment (OAT) for opioid dependence. Evidence is mixed on whether co-prescribing of sedatives such as gabapentinoids and Z-drugs during OAT increases risk of drug-related death (DRD). METHODS: We conducted a retrospective cohort study of individuals prescribed OAT between 2011 and 2020 in Scotland. Prescribing records were linked to mortality data and other healthcare datasets (sociodemographic, comorbidity). We identified episodes of treatment with gabapentinoids/Z-drugs and used multivariable quasi-Poisson regression to model associations between co-prescription and DRD risk. RESULTS: Among 46,602 individuals with 304,783 person-years of follow-up, we found that co-prescription was common, with 25 % and 34 % ever being co-prescribed gabapentinoids and Z-drugs, respectively. Gabapentinoid exposure was strongly associated (adjusted hazard ratio (aHR)=2·18, 95 % CI=1·92, 2·46) and Z-drug exposure moderately associated (aHR=1·39, 95 % CI=1·15, 1·66) with elevated risk of DRD. Gabapentinoid exposure was associated with DRD risk on and off OAT; Z-drug exposure was less strongly associated with DRD risk when on OAT. CONCLUSIONS: Co-prescription of gabapentinoids and Z-drugs is common among OAT patients. However, co-prescription is associated with increased risk of DRD. Alternatives to prescribing sedative medications to OAT patients and/or greater monitoring - if prescribed - are needed.

The synergistic anti-nociceptive effects of nefopam and gabapentinoids in inflammatory, osteoarthritis, and neuropathic pain mouse models.

Pain is a common public health problem and remains as an unmet medical need. Currently available analgesics usually have limited efficacy or are accompanied by many adverse side effects. To achieve satisfactory pain relief by multimodal analgesia, new combinations of nefopam and gabapentinoids (pregabalin/gabapentin) were designed and assessed in inflammatory, osteoarthritis and neuropathic pain. Isobolographic analysis was performed to analyze the interactions between nefopam and gabapentinoids in carrageenan-induced inflammatory pain, mono-iodoacetate-induced osteoarthritis pain and paclitaxel-induced peripheral neuropathic pain in mice. The anti-inflammatory effect and motor performance of monotherapy or their combinations were evaluated in the carrageenan-induced inflammatory responses and rotarod test, respectively. Nefopam (1, 3, 5, 10, 30 mg/kg, p.o.), pregabalin (3, 6, 12, 24 mg/kg, p.o.) or gabapentin (25, 50, 75, 100 mg/kg, p.o.) dose-dependently reversed mechanical allodynia in three pain models. Isobolographic analysis indicated that the combinations of nefopam and gabapentinoids exerted synergistic anti-nociceptive effects in inflammatory, osteoarthritis, and neuropathic pain mouse models, as evidenced by the experimental ED50 (median effective dose) falling below the predicted additive line. Moreover, the combination of nefopam-pregabalin/gabapentin alleviated carrageenan-induced inflammation and edema, and also prevented gabapentinoids-related sedation or ataxia by lowering their effective doses. Collectively, the co-administration of nefopam and gabapentinoids showed synergistic analgesic effects and may result in improved therapeutic benefits for treating pain.

Mechanisms and Preventative Strategies for Persistent Pain following Knee and Hip Joint Replacement Surgery: A Narrative Review.

Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which has the potential to decrease patient satisfaction, increase financial burden, and lead to long-term disability. The identification of risk factors for CPSP following TKA and THA is challenging but essential for targeted preventative therapy. Recent meta-analyses and individual studies highlight associations between elevated state anxiety, depression scores, preoperative pain, diabetes, sleep disturbances, and various other factors with an increased risk of CPSP, with differences observed in prevalence between TKA and THA. While the etiology of CPSP is not fully understood, several factors such as chronic inflammation and preoperative central sensitization have been identified. Other potential mechanisms include genetic factors (e.g., catechol-O-methyltransferase (COMT) and potassium inwardly rectifying channel subfamily J member 6 (KCNJ6) genes), lipid markers, and psychological risk factors (anxiety and depression). With regards to therapeutics and prevention, multimodal pharmacological analgesia, emphasizing nonopioid analgesics like acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), has gained prominence over epidural analgesia. Nerve blocks and local infiltrative anesthesia have shown mixed results in preventing CPSP. Ketamine, an N-methyl-D-aspartate (NMDA)-receptor antagonist, exhibits antihyperalgesic properties, but its efficacy in reducing CPSP is inconclusive. Lidocaine, an amide-type local anesthetic, shows tentative positive effects on CPSP. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) have mixed results, while gabapentinoids, like gabapentin and pregabalin, present hopeful data but require further research, especially in the context of TKA and THA, to justify their use for CPSP prevention.

Pregabalina preoperatoria previene las fasciculaciones y mialgias inducidas por succinilcolina: metaanálisis de ensayos aleatorizados / Preoperative pregabalin prevents succinylcholine-induced fasciculations and myalgias: A meta-analysis of randomized trials

La succinilcolina es el bloqueador neuromuscular de referencia para la inducción de secuencia rápida. Sin embargo, su uso se asocia a fasciculaciones y mialgias. Se realizó una revisión sistemática y un metaanálisis. Se incluyeron ensayos clínicos controlados aleatorizados comparando gabapentinoides frente a placebo, para la prevención de fasciculaciones y mialgias inducidas por succinilcolina. Se incluyeron seis estudios clínicos aleatorizados. El número total de pacientes fue de 481, de los cuales 241 se incluyeron en el grupo de intervención y 240 en el grupo de placebo. Los gabapentinoides redujeron la incidencia de mialgia inducida por succinilcolina (RR=0,69; IC95%: 0,56-0,84; p<0,001), que siguió siendo estadísticamente significativa para pregabalina (RR=0,71; IC95%: 0,54-0,93; p=0,013) y gabapentina (RR=0,61; IC95%: 0,45-0,82; p=0,001) por separado. No hubo diferencia entre los grupos en cuanto a fasciculaciones (RR=0,92; IC95%: 0,82-1,03; p=0,148). El uso preoperatorio de gabapentinoides se asocia a una menor incidencia de mialgias inducidas por succinilcolina dentro de las primeras 24horas posteriores al procedimiento. (AU)

Succinylcholine is the gold standard neuromuscular blocker for rapid sequence induction, however, its use is associated with fasciculations and myalgias. A systematic review and meta-analysis including randomized controlled clinical trials was performed comparing gabapentinoids versus placebo for the prevention of fasciculations and succinylcholine-induced myalgias. Six randomized clinical studies were included. The total number of patients was 481, of which 241 were in the intervention group and 240 in the placebo group. Gabapentinoids reduced the incidence of succinylcholine-induced myalgia (RR=.69; 95%CI: .56-.84; P<.001), which remained statistically significant for pregabalin (RR=.71; 95%CI: .54-.93; P=.013) and gabapentin (RR=.61; 95%CI: .45-.82; P=.001) separately. There was no difference between the groups in fasciculations (RR=.92; 95%CI: .82-1.03; P=.148). Preoperative use of gabapentinoids is associated with lower incidence of succinylcholine-induced myalgias within the first 24hours after the procedure. (AU)

A next generation peripherally restricted Cavα2δ-1 ligand with inhibitory action on Cav2.2 channels and utility in neuropathic pain.

The Voltage-Gated Calcium Channel (VGCC) auxiliary subunit Cavα2δ-1 (CACNA2D1) is the target/receptor of gabapentinoids which are known therapeutics in epilepsy and neuropathic pain. Following damage to the peripheral sensory nervous system, Cavα2δ-1 is upregulated in dorsal root ganglion (DRG) neurons in several animal models of chronic neuropathic pain. Gabapentinoids, such as gabapentin and pregabalin, engage with Cavα2δ-1 via binding an arginine residue (R241) within an RRR motif located at the N-terminus of human Cavα2δ-1. A novel, next generation gabapentinoid, engineered not to penetrate the brain, was able to generate a strong analgesic response in Chronic Constriction Injury animal model of chronic neuropathic pain and showed binding specificity for Cavα2δ-1 versus the Cavα2δ-2 subunit. This novel non-brain penetrant gabapentinoid, binds to R241 and a novel binding site on Cavα2δ-1, which is located within the VGCC_α2 domain, identified as a lysine residue within an IKAK amino acid motif (K634). The overall whole cell current amplitudes were diminished by the compound, with these inhibitory effects being diminished in R241A mutant Cavα2δ-1 subunits. The functional effects occurred at lower concentrations than those needed for inhibition by gabapentin or pregabalin, which apparently bound the Cavα2δ-1 subunit only on the R241 and not on the K634 residue. Our work sets the stage for the identification and characterisation of novel compounds with therapeutic properties in neuropathic pain and possibly in other disorders and conditions which require engagement of the Cavα2δ-1 target.

Association of Race and Ethnicity With Postoperative Gabapentinoid and Opioid Prescribing Trends for Older Adults.

BACKGROUND: Disparities in opioid prescribing by race/ethnicity have been described in many healthcare settings, with White patients being more likely to receive an opioid prescription than other races studied. As surgeons increase prescribing of nonopioid medications in response to the opioid epidemic, it is unknown whether postoperative prescribing disparities also exist for these medications, specifically gabapentinoids. METHODS: We conducted a retrospective cohort study using a 20% Medicare sample for 2013-2018. We included patients ≥66 years without prior gabapentinoid use who underwent one of 14 common surgical procedures. The primary outcome was the proportion of patients prescribed gabapentinoids at discharge among racial and ethnic groups. Secondary outcomes were days' supply of gabapentinoids, opioid prescribing at discharge, and oral morphine equivalent (OME) of opioid prescriptions. Trends over time were constructed by analyzing proportion of postoperative prescribing of gabapentinoids and opioids for each year. For trends by year by racial/ethnic groups, we ran a multivariable logistic regression with an interaction term of procedure year and racial/ethnic group. RESULTS: Of the 494,922 patients in the cohort (54% female, 86% White, 5% Black, 5% Hispanic, mean age 73.7 years), 3.7% received a new gabapentinoid prescription. Gabapentinoid prescribing increased over time for all groups and did not differ significantly among groups (P = 0.13). Opioid prescribing also increased, with higher proportion of prescribing to White patients than to Black and Hispanic patients in every year except 2014. CONCLUSIONS: We found no significant prescribing variation of gabapentinoids in the postoperative period between racial/ethnic groups. Importantly, we found that despite national attention to disparities in opioid prescribing, variation continues to persist in postoperative opioid prescribing, with a higher proportion of White patients being prescribed opioids, a difference that persisted over time.

Patterns of filled prescriptions and the association with risk of drug-induced death. A population-based nested case-control register study.

PURPOSE: Opioid analgesics (OA) and other pharmaceuticals have been associated with drug-induced deaths. However, there is a lack of knowledge regarding patterns of use of these pharmaceuticals in the population and regarding such associations. We identify and describe subgroups of people with different patterns of filled prescriptions of OA and other relevant pharmaceuticals and examine associations with drug-induced deaths. In addition, we estimate the proportion of drug-induced deaths with a filled OA prescription and OA as cause of death. METHODS: A Norwegian population-based nested case-control register study with cases (drug-induced deaths 2010-2018, N = 2388) and population controls matched for age, gender and year of inclusion (N = 21 465). Patterns of filled prescriptions for opioid analgesics (OA), benzodiazepines and benzodiazepine-related drugs, gabapentinoids, ADHD medication and antidepressants/antipsychotics were explored by k-means cluster analysis. Associations with drug-induced deaths were estimated by conditional logistic regression adjusted for sociodemographic characteristics. Overlap of filled OA prescriptions and OA as cause of death was estimated. RESULTS: Five clusters were identified: 'few prescriptions', 'weak OA', 'ADHD medication', 'sedative/psychiatric morbidity' and 'strong OA'. The 'strong OA' cluster had higher socioeconomic status compared to the other groupings. The risk of drug-induced death was also highest in this cluster (OR = 35.5; CI 25.6-49.3) and, for 68% (CI 64-73) of cases, filled prescriptions for OA was indicated as the underlying cause of death. CONCLUSIONS: The cluster analysis identified a subgroup with filled prescriptions of OA and other pharmaceuticals and a higher socioeconomic status than other subgroups. This subgroup had a high risk of drug-induced death that needs to be addressed.

Update to Gabapentinoid Use in the United States, 2002-2021.

Gabapentinoids are commonly used medications for numerous off-label conditions. The 2002-2021 Medical Expenditure Panel Survey (MEPS) was used to investigate the proportion of the adult population who were gabapentinoid users, the ages of these users, medications and diagnoses associated with users, and the likelihood of starting, stopping, or continuing gabapentinoids. Gabapentinoid users continued to increase since our last publication from 4.0% in 2015 to 4.7% in 2021. Gabapentinoid use was much more likely among individuals who used other medications used in chronic pain. Between 2017-2021, numerous chronic pain conditions were associated with gabapentinoid use. New gabapentinoid users clearly outnumbered gabapentinoid stoppers between 2011-2012 and 2017-2018, but this difference decreased in the most recent cohorts.

A Literature Review: The Mechanisms and Treatment of Neuropathic Pain-A Brief Discussion.

Classically, neuropathic pain is described as a pain caused by a lesion or disease of the somatosensory system. However, one must note that the presence of somatosensory pathology alone does not guarantee a progression to neuropathic pain. This is due, in part, to the fact that neuropathic pain is a notoriously complex disease process, involving sensitization of both the central and peripheral nervous systems. Its causes are also numerous and varied, including trauma, the compression of a nerve, autoimmune disorders, diabetes, and infections. Due to the various manifestations, causes, and symptoms of neuropathic pain, the treatment of this disease process has proved challenging for generations of physicians. This section aims to elaborate on newly proposed mechanisms for pharmacological and targeted therapies, such as neurostimulation, which aim to reduce the negative somatosensory effects of neuropathic pain.

Signal detection of adverse events associated with gabapentinoid use for chronic pain.

INTRODUCTION: Gabapentinoids (GABA) prescribing as a potential and conceivably safer substitute for opioids has substantially increased. Understanding all potential adverse drug events (ADEs) associated with GABA will guide clinical decision-making for pain management. METHODS: A 20% sample of Medicare enrollees with new chronic pain diagnoses in 2017-2018 was selected. GABA users were those with >=30 consecutive days prescription in a year without opioid prescription. Opioid users were similarly defined. The control group used neither of these drugs. Propensity score match across three groups based on demographics and comorbidity was performed. We used proportional reporting ratio (PRR), Gamma Poisson Shrinker, and tree-based scan statistic (TBSS) to detect ADEs within 3, 6, and 12 months of follow-up. RESULTS: Immunity disorder was detected within 3 months of follow-up by PRR compared to opioid use (PRR:2.33), and by all three methods compared to controls. Complications of transplanted organs/tissues and schizophrenia spectrum/other psychotic disorders were consistently detected by PRR and TBSS within 3 months. Skin disorders were detected by TBSS; and stroke was detected by PRR within 3 months compared to opioid use (PRR:4.74). Some malignancies were detected by PRR within 12 months. Other signals detected in GABA users were neuropathy and nerve disorders. CONCLUSIONS: Our study identified expected and unexpected ADE signals in GABA users. Neurological signals likely related to indications for GABA use. Signals for immunity, mental/behavior, and skin disorders were found in the FDA adverse event reporting system database. Unexpected signals of stroke and cancer require further confirmatory analyses to verify.

Prescription opioid use among people with opioid dependence and concurrent benzodiazepine and gabapentinoid exposure: An analysis of overdose and all-cause mortality.

BACKGROUND: Studies investigating mortality risk associated with use of opioid analgesics, benzodiazepines, gabapentinoids, and opioid agonist treatment (OAT) among people with opioid dependence (PWOD) are lacking. This study addresses this gap using a cohort of 37,994 PWOD initiating opioid analgesics between July 2003 and July 2018 in New South Wales, Australia. METHODS: Linked administrative records provided data on dispensings, sociodemographics, clinical characteristics, OAT, and mortality. Cox proportional hazards models assessed associations between time-varying measures of individual and concurrent medicine use and OAT with all-cause mortality, accidental opioid overdose, non-drug induced accidents, and non-drug-induced suicide. Opioid analgesic dose effects, expressed as oral morphine equivalents (OMEs) per day, were also examined. OUTCOMES: During the study period, 3167 individuals died. Compared with no use, all medicines of interest were associated with increased accidental opioid overdose risk; hazard ratios (HR) ranged from 1.33 (95 % CI: 1.05-1.68) for opioid analgesic use to 6.10 (95 % CI: 4.11-9.06) for opioid analgesic, benzodiazepine and gabapentinoid use. Benzodiazepine use was associated with increased non-drug-induced accidents and non-drug-induced suicides. For all-cause mortality, all combinations of benzodiazepines and gabapentinoids with opioid analgesics were associated with increased risk (aHRs ranged from 1.35 to 2.73). For most medicines/medicine combinations, all-cause mortality risk was reduced when in OAT compared to out of OAT. Higher opioid analgesic doses were associated with increased all-cause mortality (e.g., 90-199 mg vs 1-49 mg OME per day: HR 1.90 [95 % CI: 1.52-2.40]). INTERPRETATION: The increased mortality risk associated with benzodiazepines and gabapentinoids among PWOD appear to be reduced when engaged in OAT. A greater focus on encouraging OAT engagement, providing overdose prevention education, and access and coverage of overdose antidotes is necessary to minimise the unintended consequences of medicines use in this population.

Pain Control Associated With Gabapentinoid Prescription After Elective Total Knee Arthroplasty.

BACKGROUND: Gabapentinoid (GABA) prescribing has substantially increased as a nonopioid analgesics for surgical conditions. We examined the effectiveness of GABA use for postoperative pain control among patients receiving total knee arthroplasty (TKA). METHODS: This retrospective cohort study using 2016 to 2019 data from a 20% national sample of Medicare enrollees included patients aged 66 and over years who received an elective TKA, were discharged to home, received home health care, and had both admission and discharge assessments of pain (n = 35,186). Study outcomes were pain score difference between admission and discharge and less-than-daily pain interfering with activity at discharge. Opioid and GABA prescriptions after surgery and receipt of nerve block within 3 days of surgery were also assessed. RESULTS: There were 30% of patients who had a pain score decrease of 3 to 4 levels and 55.8% had pain score decreases of 1 to 2 levels. In multivariable analyses, receiving a nerve block was significantly associated with pain score reduction. A GABA prescription increased the magnitude of pain score reduction among those receiving a nerve block. Results from inverse probability weighted analysis with propensity score showed that coprescribing of GABA and low-dose opioid was associated with significantly lower pain scores. CONCLUSIONS: Post-TKA opioid use was not associated with pain score reduction. Receiving a nerve block was associated with a modest pain score reduction. Co-prescribing GABA with low-dose opioid or receiving a nerve block was associated with increasing magnitudes of pain reduction. Further research should identify alternatives to opioid use for managing postoperative TKA pain.

Drug clustering to anticipate new aspects of drug safety profile: Application to gabapentinoids and other voltage-gated calcium channel ligand drugs.

AIMS: Gabapentin and pregabalin bind to α2-δ subunit of voltage-gated calcium channels (Cav ). Other drugs targeting Cav include cardiovascular calcium channel blockers (CCBs) and anticonvulsants (levetiracetam, ethosuximide and zonisamide). In addition to pharmacodynamics, the safety profile of gabapentinoids seems to overlap with the one of cardiovascular CCBs (oedema) and Cav -blocking anticonvulsants (suicide and ataxia). The objective of this study was to cluster the safety profile of different Cav -ligand drugs by focusing on whether gabapentinoids present a distinct adverse drug reaction (ADR) signature from cardiovascular CCBs and anticonvulsants. METHODS: We extracted all ADRs with at least one significant disproportionate reporting (reporting odds ratio) related to gabapentinoids, CCBs or anticonvulsants in VigiBase. After principal component analysis preprocessing, a hierarchical ascendent classification was performed to cluster gabapentinoids and other Cav -ligand drugs that share a similar ADR signature. The robustness of the results was determined through four sensitivity analyses, varying on the dataset or the clustering method. RESULTS: A total of 16 drugs and 65 ADRs were included. Gabapentinoids were in Cluster #1, which included eight other drugs (isradipine, nicardipine, lacidipine, lercanidipine, ethosuximide, levetiracetam, zonisamide and nimodipine). Cluster #2 contained two drugs (diltiazem and verapamil) and Cluster #3 contained four drugs (amlodipine, felodipine, nifedipine and nitrendipine). The clustering results were consistent in all sensitivity analyses. CONCLUSIONS: The safety profile of gabapentinoids overlaps with those of some dihydropyridine CCBs and Cav -blocking anticonvulsants. These results could be used to anticipate some unidentified ADRs of gabapentinoids from information accumulated with older drugs and sharing a common molecular target and ADR signature.

Efficacy and safety of pregabalin and gabapentin in spinal stenosis: a systematic review and meta-analysis.

Background and Objective: Multimodal management of spinal stenosis is on the rise, and central sensitisation inhibitors are playing an essential role in the treatment of central sensitisation processes. Pregabalin and gabapentin are antiepileptic drugs that decrease presynaptic excitability. The aim of this study was to investigate whether the use of pregabalin and gabapentin is effective in the symptomatic management of spinal stenosis, compared to other drugs, by using pain and disability rating scales. We also assessed the safety profile associated with these drugs. Methods: We conducted a bibliographic search in the Pubmed, Web of Science, and Cochrane Collaboration Library databases. The inclusion criteria were studies that compared pregabalin or gabapentin to a control group in patients with lumbar spinal stenosis. We included randomized clinical trialsand a comparative retrospective cohort study. The primary clinical endpoints were VAS/NRS and ODI, measured at two, four, 8 weeks, and 3 months, while adverse events and walking distance were also collected. We combined the data using Review Manager 5.4 software. Results: Our meta-analysis included six studies with a total of 392 patients, with a mean age of 60.3 years. We observed no significant differences in VAS scores at two, four, and 8 weeks: MD: 0.23, 95% CI: 0.63 to 1.09; MD: -0.04, 95% CI: -0.64 to -0.57; and MD: -0.6, 95% CI: -1.22 to 0.02, respectively. However, at 3 months, we found significant differences in favor of pregabalin with respect to VAS: MD: -2.97, 95% CI: -3.43 to -2.51. We did not observe significant differences respect to the ODI: MD: -3.47, 95% CI: -7.15 to -0.21. Adverse events were significantly higher in the pregabalin/gabapentin group (OR 5.88, 95% CI: 1.28-27.05). Conclusion: Our meta-analysis suggests that abapentinoids may have a significant effect on VAS score at 3 months, but no significant differences were observed in ODI scores, and adverse events were higher in the gabapentinoids group.

Postmastectomy Pain Syndrome: A Narrative Review.

Postmastectomy pain syndrome is a very common disorder in breast cancer survivors. The impact on the quality of patients' lives is significantly adverse. The precise pathophysiology has not been determined as yet though various risk factors have been identified that make the patient vulnerable. Required preoperative work includes the identification and possible elimination of risk factors. Treatment is multidisciplinary involving surgical and non-surgical modalities. There is a great scope of research in this field.