Mechanism of gabapentinoid potentiation of opioid effects on cyclic AMP signaling in neuropathic pain.

Over half of spinal cord injury (SCI) patients develop opioid-resistant chronic neuropathic pain. Safer alternatives to opioids for treatment of neuropathic pain are gabapentinoids (e.g., pregabalin and gabapentin). Clinically, gabapentinoids appear to amplify opioid effects, increasing analgesia and overdose-related adverse outcomes, but in vitro proof of this amplification and its mechanism are lacking. We previously showed that after SCI, sensitivity to opioids is reduced by fourfold to sixfold in rat sensory neurons. Here, we demonstrate that after injury, gabapentinoids restore normal sensitivity of opioid inhibition of cyclic AMP (cAMP) generation, while reducing nociceptor hyperexcitability by inhibiting voltage-gated calcium channels (VGCCs). Increasing intracellular Ca2+ or activation of L-type VGCCs (L-VGCCs) suffices to mimic SCI effects on opioid sensitivity, in a manner dependent on the activity of the Raf1 proto-oncogene, serine/threonine-protein kinase C-Raf, but independent of neuronal depolarization. Together, our results provide a mechanism for potentiation of opioid effects by gabapentinoids after injury, via reduction of calcium influx through L-VGCCs, and suggest that other inhibitors targeting these channels may similarly enhance opioid treatment of neuropathic pain.

Brain α2δ-1-Bound NMDA Receptors Drive Calcineurin Inhibitor-Induced Hypertension.

BACKGROUND: Calcineurin is highly enriched in immune T cells and the nervous system. Calcineurin inhibitors, including cyclosporine and tacrolimus (FK506), are the cornerstone of immunosuppressive regimens for preserving transplanted organs and tissues. However, these drugs often cause persistent hypertension owing to excess sympathetic outflow, which is maintained by N-methyl-D-aspartate receptor (NMDAR)-mediated excitatory input to the hypothalamic paraventricular nucleus (PVN). It is unclear how calcineurin inhibitors increase NMDAR activity in the PVN to augment sympathetic vasomotor activity. α2δ-1 (encoded by the Cacna2d1 gene), known colloquially as a calcium channel subunit, is a newly discovered NMDAR-interacting protein. In this study, we determined whether α2δ-1 plays a role in calcineurin inhibitor-induced synaptic NMDAR hyperactivity in the PVN and hypertension development. METHODS: Immunoblotting and coimmunoprecipitation assays were used to quantify synaptic protein levels and the physical interaction between GluN1 (the obligatory NMDAR subunit) and α2δ-1. Whole-cell patch-clamp recordings of retrogradely labeled, spinally projecting PVN were conducted in perfused brain slices to measure presynaptic and postsynaptic NMDAR activity. Radio-telemetry was implanted in rodents to continuously record arterial blood pressure in conscious states. RESULTS: Prolonged treatment with FK506 in rats significantly increased protein levels of α2δ-1, GluN1, and the α2δ-1-GluN1 complex in PVN synaptosomes. These effects were blocked by inhibiting α2δ-1 with gabapentin or interrupting the α2δ-1-NMDAR interaction with an α2δ-1 C-terminus peptide. Treatment with FK506 potentiated the activity of presynaptic and postsynaptic NMDARs in spinally projecting PVN neurons; such effects were abolished by gabapentin, Cacna2d1 knockout, or α2δ-1 C-terminus peptide. Furthermore, microinjection of α2δ-1 C-terminus peptide into the PVN diminished renal sympathetic nerve discharges and arterial blood pressure that had been increased by FK506 treatment. Remarkably, concurrent administration of gabapentin prevented the development of FK506-induced hypertension in rats. Additionally, FK506 treatment induced sustained hypertension in wild-type mice but not in Cacna2d1 knockout mice. CONCLUSIONS: α2δ-1 is essential for calcineurin inhibitor-induced increases in synaptic NMDAR activity in PVN presympathetic neurons and sympathetic outflow. Thus, α2δ-1 and α2δ-1-bound NMDARs represent new targets for treating calcineurin inhibitor-induced hypertension. Gabapentinoids (gabapentin and pregabalin) could be repurposed for treating calcineurin inhibitor-induced neurogenic hypertension.

Ameliorative effect of nano-pregabalin in gastrocnemius muscle of gamma irradiated rats with an experimental model of fibromyalgia: Crosstalk of Sirt3, IL-1ß and PARP1 pathways.

BACKGROUND: Fibromyalgia (FM) is a complex syndrome with somatic symptoms connected to the operational state of muscles. Although radiotherapy is a cornerstone in cancer treatment, it is implicated in the aggravation of FM. Lately, formulation of medicines in nano-forms become of great prominence due to their prospective applications in medicine. So, this study aimed to assess possible therapeutic benefits of formulating pregabalin in a nono-form (N-PG) for managing FM during exposure to gamma radiation. METHODS: Gamma rays administered in fractionated doses (2 Gy/day) to male rats after one hour of s.c. injection of reserpine (1 mL/kg per day) to induce FM, then treated with single daily dose of (30 mg/kg, p.o.) PG or N-PG for ten successive days. Rats were subjected to behavioral tests, then sacrificed to obtain serum and gastrocnemius muscles. RESULTS: N-PG significantly antagonized reserpine-induced FM as proved by; the immobility and performance times in forced swim and rotarod performance tests, respectively were restored near to the normal time, serum IL-8 and MCP-1 chemokines were nearby the normal levels, mitigated oxidative stress through increasing total thiol, Sirt3, CAT enzyme and decreasing COX-1, inhibition of inflammation via IL-1ß and MIF significant reduction, it possessed anti-apoptotic effect verified by decreasing PARP-1 and increasing Bcl-XL, gastrocnemius muscles had minimal fibrosis levels as seen after Masson trichrome staining. Histopathological results were coincidence with biochemical inspection. CONCLUSION: This study identifies N-PG as a novel drug that could be of a value in the management of FM particularly in cancer patients undergoing radiotherapy.

Influence of the calcium voltage-gated channel auxiliary subunit (CACNA2D1) absence on intraocular pressure in mice.

The etiology of elevated intraocular pressure (IOP), a major risk factor for glaucoma (optic nerve atrophy), is poorly understood despite continued efforts. Although the gene variant of CACNA2D1 (encoding α2δ1), a calcium voltage-gated channel auxiliary subunit, has been reported to be associated with primary open-angle glaucoma, and the pharmacological mitigation of α2δ1 activity by pregabalin lowers IOP, the cellular basis for α2δ1 role in the modulation of IOP remains unclear. Our recent findings reveled readily detectable levels of α2δ1 and its ligand thrombospondin in the cytoskeletome fraction of human trabecular meshwork (TM) cells. To understand the direct role of α2δ1 in the modulation of IOP, we evaluated α2δ1 null mice for changes in IOP and found a moderate (∼10%) but significant decrease in IOP compared to littermate wild type control mice. Additionally, to gain cellular insights into α2δ1 antagonist (pregabalin) induced IOP changes, we assessed pregabalin's effects on human TM cell actin cytoskeletal organization and cell adhesive interactions in comparison with a Rho kinase inhibitor (Y27632), a known ocular hypotensive agent. Unlike Y27632, pregabalin did not have overt effects on cell morphology, actin cytoskeletal organization, or cell adhesion in human TM cells. These results reveal a modest but significant decrease in IOP in α2δ1 deficient mice, and this response appears to be not associated with the contractile and cell adhesive characteristics of TM cells based on the findings of pregabalin effects on isolated TM cells. Therefore, the mechanism by which pregabalin lowers IOP remains elusive.

Edema related to treatment with psychotropic drugs.

Edema as an adverse drug reaction is a commonly underestimated yet potentially debilitating condition. This study analyzes the incidence of severe psychotropic drug-induced edema (e.g., edema affecting the face, legs, or multiple body parts and lasting for more than 1 week, or in any case necessitating subsequent diuretic use) among psychiatric inpatients. The cases under examination are derived from an observational pharmacovigilance program conducted in German-speaking countries ("Arzneimittelsicherheit in der Psychiatrie", AMSP) from 1993 to 2016. Among the 462,661 inpatients monitored, severe edema was reported in 231 cases, resulting in an incidence of 0.05%. Edema occurred more frequently in women (80% of all cases) and older patients (mean age 51.8 years). Pregabalin had the highest incidence of severe edema, affecting 1.46‰ of patients treated with pregabalin, followed by mirtazapine (0.8‰). The majority of edema cases showed a positive response to appropriate countermeasures, such as dose reduction and drug discontinuation, and resolved by the end of the observation period. While most instances of drug-induced edema are reversible, they can have a significant impact on patient well-being and potentially result in decreased treatment adherence. It is, therefore, crucial to remain vigilant regarding risk-increasing circumstances during treatment with psychotropic drugs.

In vitro models for neuropathic pain phenotypic screening in brain therapeutics.

The discovery of brain therapeutics faces a significant challenge due to the low translatability of preclinical results into clinical success. To address this gap, several efforts have been made to obtain more translatable neuronal models for phenotypic screening. These models allow the selection of active compounds without predetermined knowledge of drug targets. In this review, we present an overview of various existing models within the field, examining their strengths and limitations, particularly in the context of neuropathic pain research. We illustrate the usefulness of these models through a comparative review in three crucial areas: i) the development of novel phenotypic screening strategies specifically for neuropathic pain, ii) the validation of the models for both primary and secondary screening assays, and iii) the use of the models in target deconvolution processes.

Gabapentinoids in Ireland 2010 to 2020: An observational study of trends in gabapentinoid prescribing, law enforcement drug seizures and postmortem toxicology.

AIMS: We explored trends in gabapentinoid prescribing, drug seizures and postmortem toxicology using a national pharmacy claims database, law enforcement drug seizures data and a population-based postmortem toxicology database. METHODS: Gabapentinoid prescribing rates per 100 000 eligible population (2010-2020), annual number of drug seizures involving gabapentinoids (2012-2020) and gabapentinoid detection (positive) rates per 100 postmortem toxicology case (2013-2020) were calculated. Negative binomial regression models were used to evaluate longitudinal trends for gabapentin and pregabalin separately. RESULTS: Gabapentin (adjusted rate ratio [RR] 1.06, 95% confidence interval [CI] 1.05-1.06, P < .001) and pregabalin (adjusted RR 1.08, 95% CI 1.08-1.09, P < .001) prescribing increased annually, with higher rates of pregabalin (vs. gabapentin) observed every year. Drug seizures involving pregabalin also increased over time (RR 1.54 95% CI 1.25-1.90, P < .0001). Of the 26 317 postmortem toxicology cases, 0.92% tested positive for gabapentin, and 6.37% for pregabalin. Detection rates increased for both gabapentin (RR 1.28, 95% CI 1.11-1.48, P < .001) and pregabalin (RR 1.13, 95% CI 1.11-1.48, P < .001) between 2013 and 2020. A total of 1901 cases (7.2%) tested positive for heroin/methadone; this sub-group had a higher detection rate for pregabalin (n = 528, 27.8%) and gabapentin (n = 41, 2.2%) over the study period, with a high burden of codetections for pregabalin with benzodiazepines (peaking at 37.3% in 2018), and pregabalin with prescription opioids (peaking at 28.9% in 2020). CONCLUSION: This study raises concerns regarding the wide availability of pregabalin in Ireland, including a growing illicit supply, and the potential for serious harm arising from poly drug use involving pregabalin among people who use heroin or methadone.

History of Preoperative Use of Gabapentin Before Lower Extremity Bypass Predisposes Patients to a High Risk of Opioid Use and Dependence in a Dose-dependent Manner.

INTRODUCTION: This study assesses the association of preoperative use of gabapentinoids (GBPs) with postoperative risk of opioid-related disorders in peripheral artery disease patients undergoing lower extremity bypass operation. METHODS: This is a retrospective propensity score-matched analysis of patients undergoing peripheral artery bypass in TriNetX, a multicenter national database. Two study groups were constituted based on the preoperative history of prescribed GBPs. Primary outcomes were opioid-related disorders and mortality. The outcomes were reported at two-time endpoints that is, at 1 and 5 y. RESULTS: This study population included a total of 23,706 patients. After propensity score-matched analysis, each group contained 5130 patients. The primary outcomes showed a significant increase in postoperative opioid-related disorders at the 1 and 5-y time points between GBPs and no GBPs groups: 1-y outcome (2.0% versus 1.1%; adj. P = 0.007) and 5-y outcome (4.5% versus 3.5%; adj. P = 0.035). Logistic regression analysis revealed an increase in the 1-y (adjusted odds ratio= 1.664; 95% CI [1.217, 2.273], P = 0.001) and 5-y (OR = 1.353; 95% CI [1.107, 1.653], P = 0.003) odds of opioid-related disorders in patients on GBPs. A secondary analysis showed a significant dose-dependent increase in the associated risk of 5-y opioid-related disorders in patients with a history of prescribed gabapentin. CONCLUSIONS: In patients undergoing lower extremity bypass with a history of gabapentin use, there is an associated increased long-term risk of opioid-related disorders in a dose-dependent fashion. Overall, this study highlights weighing risks and benefits of prescribing GBPs for pain control versus their long-term associated risk of opioid-related disorders among other adverse outcomes.

Pregabalin Does Not Increase Risk of Heart Failure Exacerbation in Patients With Pre-existing Heart Failure.

BACKGROUND: Through actions of calcium channel trafficking inhibition and sodium/water retention, pregabalin may increase the risk of acute heart failure (AHF). OBJECTIVE: The objective of this study was to determine the prevalence of heart failure (HF) acute exacerbations, measured by a composite of emergency department (ED) visits, per-patient per-year (PPPY) hospitalizations, time-to first ED admission, and time-to hospitalizations in pre-existing HF patients taking pregabalin compared with those who were pregabalin-naive. METHODS: A retrospective cohort study of pregabalin users with HF were propensity score-matched to pregabalin-naïve patients with HF to evaluate the composite of ED admissions or PPPY hospitalizations, time-to first ED admission, and time-to hospitalizations during the 365 days post-index. Doubly robust generalized linear regression and Cox-proportional hazard regression modeling were undertaken for analysis of differences between groups. RESULTS: The matched cohort of 385 pregabalin users and 3460 pregabalin nonusers were principally middle-aged, equally gender distributed, and primary Caucasian. Most patients were on guideline-directed HF medical therapy. The estimated cumulative incidence of the primary outcome was a hazard ratio of 1.099 (95% CI: 0.789-1.530; P = 0.58). CONCLUSION AND RELEVANCE: This large, single-center, cohort study shows pregabalin is not associated with an increased risk of AHF events in patients with pre-existing HF.

Enhancing the imidase activity of BpIH toward 3-isobutyl glutarimide via semi-rational design.

(R)-3-Isobutylglutarate monoamide (R-IBM) is a key intermediate in the synthesis of the analgesic drug pregabalin. Recently, the imidase BpIH derived from Burkholderia phytofirmans was identified as a promising catalyst for the industrial production of R-IBM. Notably, this catalyst has the distinct advantage of achieving a 100% theoretical yield from 3-isobutyl glutarimide (IBI). In this study, homology modeling and structure alignment techniques were used to determine the substrate binding pocket of BpIH. Semi-rational design was used to analyze the amino acid residue conservation in the binding pocket region of BpIH. Interestingly, mutations of several low-conserved amino acid located 6-9 Å from the substrate significantly enhanced the catalytic activity of BpIH. Among them, the triple mutant Y37FH133NS226I (YHS-I) showed approximately a fivefold increase in enzyme activity and a significantly improved catalytic efficiency (kcat/Km). Under the same reaction time and conditions, YHS-I successfully converted IBI into R-IBM with a conversion rate of 88.87%, with an enantiomeric excess (ee) of the product exceeding 99.9%. In comparison, wild-type BpIH had a conversion rate of only 38.15%. Molecular dynamics and docking results indicated that YHS-I had higher rigidity around the mutation sites. The synergistic substitutions of Y37F, H133N, and S226I altered the interaction network within the mutation site, enhancing the protein's affinity for the substrate and improving catalytic efficiency. KEY POINTS: • 100% theoretical yield of R-IBM by BpIH compared with 50% by resolution • Semi-rational design of BpIH based on conservativity with homologous enzymes • Mutant with enzyme activity of sixfold and product ee value of 99.9.

The Effect of Pregabalin on Microglia Differentiation in Rat with Neuropathic pain: A Preliminary Study.

This study investigated the effects of pregabalin on microglial differentiation in rats with neuropathic pain (NP) induced by sciatic nerve ligation and transection. After confirming NP, the rats were randomly allocated to either a pregabalin or control group. The pregabalin group received intraperitoneal injections of 10 mg/kg pregabalin, while the control group received an equivalent volume of normal saline following surgery. On postoperative day 28, neuronal damage, microglial activity, and microglial differentiation were assessed. The pregabalin group exhibited significantly less neuronal damage compared to the control group, along with a significant decrease in activated microglial expression in both the brain and spinal cord. Pregabalin treatment also significantly altered the microglial phenotype expression, with a decrease in the M1 phenotype percentage and an increase in the M2 phenotype percentage in both the brain (M1 phenotype: 43.52 ± 12.16% and 18.00 ± 8.57% in the control and pregabalin groups, respectively; difference: 27.26 [15.18-42.10], p = 0.002; M2 phenotype: 16.88 ± 6.47% and 39.63 ± 5.82% in the control and pregabalin groups, respectively; difference 22.04 [17.17-32.70], p < 0.001) and the spinal cord ipsilateral to nerve injury (M1 phenotype: 44.35 ± 12.12% and 13.78 ± 5.39% in the control and pregabalin groups, respectively; difference 30.46 [21.73-44.45], p < 0.001; M2 phenotype: 7.64 ± 3.91% and 33.66 ± 7.95% in the control and pregabalin groups, respectively; difference 27.41 [21.21-36.30], p < 0.001). Overall, pregabalin treatment significantly decreased the microglial M1 phenotype while increasing the microglial M2 phenotype in NP rats.

Neuropsychiatric Effects Associated with Opioid-Based Management for Palliative Care Patients.

PURPOSE OF REVIEW: The abundance of opioids administered in the palliative care setting that was once considered a standard of care is at present necessitating that providers evaluate patients for unintentional and deleterious symptomology related to aberrant opioid use and addiction. Polypharmacy with opioids is dynamic in affecting patients neurologically, and increased amounts of prescriptions have had inimical effects, not only for the individual, but also for their families and healthcare providers. The purpose of this review is to widen the perspective of opioid consequences and bring awareness to the numerous neuropsychiatric effects associated with the most commonly prescribed opioids for patients receiving palliative care. RECENT FINDINGS: Numerous clinical and research studies have found evidence in support for increased incidence of opioid usage and abuse as well as undesirable neurological outcomes. The most common and concerning effects of opioid usage in this setting are delirium and problematic drug-related behavioral changes such as deceitful behavior towards family and physicians, anger outbursts, overtaking of medications, and early prescription refill requests. Other neuropsychiatric effects detailed by recent studies include drug-seeking behavior, tolerance, dependence, addictive disorder, anxiety, substance use disorder, emotional distress, continuation of opioids to avoid opioid withdrawal syndrome, depression, and suicidal ideation. Opioid usage has detrimental and confounding effects that have been overlooked for many years by palliative care providers and patients receiving palliative care. It is necessary, even lifesaving, to be cognizant of potential neuropsychiatric effects that opioids can have on an individual, especially for those under palliative care. By having an increased understanding and awareness of potential opioid neuropsychiatric effects, patient quality of life can be improved, healthcare system costs can be decreased, and patient outcomes can be met and exceeded.

Diabetic Neuropathy: A Guide to Pain Management.

PURPOSE OF REVIEW: Diabetic neuropathy is a common complication of diabetes mellitus (DM) and can affect up to 50% of DM patients during their lifetime. Patients typically present with numbness, tingling, pain, and loss of sensation in the extremities. Since there is no treatment targeting the underlying mechanism of neuropathy, strategies focus on preventative care and pain management. RECENT FINDINGS: Up to 69% of patients with diabetic neuropathy receive pharmacological treatment for neuropathic pain. The United States Food and Drug Administration (FDA) confirmed four drugs for painful diabetic neuropathy (PDN): pregabalin, duloxetine, tapentadol, and the 8% capsaicin patch. Nonpharmacological treatments such as spinal cord stimulation (SCS) and transcutaneous electrical nerve stimulation (TENS) both show promise in reducing pain in DM patients. Despite the high burden associated with PDN, effective management remains challenging. This update covers the background and management of diabetic neuropathy, including its epidemiology, pathogenesis, preventative care, and current therapeutic strategies.

Gabapentinoid prescribing patterns and predictors utilizing neural networks: An analysis across emergency departments Nationwide between 2012 and 2021.

BACKGROUND: Gabapentinoids increasingly utilized for neuropathic pain, possibly to curb opioid prescribing. At the same time, data suggest subsequent increases in misuse and overdose of gabapentinoids, often in mixed overdoses. We sought to determine national trends and characteristics of gabapentinoid prescribing, including co-use with opioids, from the emergency department (ED). METHODS: This is a retrospective review of the National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2012 to 2021. Our primary outcome was the trend in ED visits in which gabapentinoids were prescribed at discharge. Secondarily, we identified trends in gabapentinoid and opioid co-prescribing and gabapentin and pregabalin prescribing at ED discharge. We examined demographic data and used descriptive statistics, Shapiro Wilke's test, Pearson's Spearman's rho (SR) or Pearson's correlation coefficient (PC) as applicable. Neural networks were used to identify the most important predictors of opioid utilization during the same visit. RESULTS: Between 2012 and 2021, there were an estimated 7,242,694 (0.53% of all ED visits) visits in which gabapentinoids were prescribed at ED discharge. Prescriptions increased from a total of 138,479 (0.1%) in 2012 to 893,495 (0.63%) in 2021 (PC: 0.85, p < 0.001). Opioids were co-prescribed in 27.2% of all visits in which gabapentinoids were prescribed, with no change over time (PC: -0.47, p = 0.09). Pregabalin prescription increased linearly over time (PC: 0.64, p = 0.02). The most important predictors of opioid administration or co-prescribing were whether an alternative provider (e.g., consult or nurse practitioner) saw the patient (100%), insurance (94.4%), age (75.9%), and region (75.2%). CONCLUSION: Despite an association of misuse and overdose, often associated with opioids, gabapentinoids were increasingly prescribed at ED discharge. While these agents may be safer alternatives to opioids, misuse may be an associated consequence of increased prescribing, which warrants further investigation.

Protective effect of pregabalin on renal and renal endothelial damage in sepsis induced by lipopolysaccharide.

OBJECTIVE: We investigated the protective effects of pregabalin (PRG) on kidney and renal endothelial damage in sepsis induced by Lipopolysaccharide (LPS). MATERIALS AND METHODS: Rats were randomly divided into three groups as control, LPS and LPS+PRG. Saline solution was administered 30 mg/kg orally and 5 mg/kg intraperitoneally (i.p.) to the control group. LPS was applied as 5 mg/kg, i.p. to the LPS group. In the LPS+PRG group, PRG at 30 mg/kg orally and one hour before LPS administration, one hour later 5 mg/kg i.p. LPS was applied. Rats were sacrificed 6 hours after LPS administration. RESULTS: White Blood Cell (WBC), granulocyte, Blood Urea Nitrogen (BUN), creatinine, uric asid, Total Oxidant Status (TOS) and Oxidative Stress Index (OSI) significantly increased (p<0.05); platelets (PLT), activated partial thromboplastin time (aPTT) and Total Antioxidant Status (TAS) significantly decreased in the LPS group compared to the control group (p<0.05). In the LPS+PRG group WBC, granulocyte, BUN, creatinine, uric asid, TOS and OSI significantly decreased (p<0.05); PLT, aPTT and TAS significantly increased compared to the LPS group(p<0.05). Histopathological examinations showed that kidney and renal endothelial damage in the LPS group decreased in the LPS+PRG group. Immunohistochemically IL1-ß, IL-6, IL-10, TNF-α expressions in kidney tissue and Toll-Like Receptors-4 (TLR-4) and NF-κB expressions in the renal endothelial tissue significantly increased in the LPS group compared to the control group and significantly decreased in the LPS+PRG group compared to the LPS group (p<0.001). CONCLUSIONS: Sepsis causes kidney and renal endothelial damage and PRG reduces this damage. Therefore PRG can be used in prophylactic treatment in sepsis, supported by more studies.

In this study, kidney and renal endothelial damage in sepsis was investigated. The effect of pregabalin on kidney and renal endothelial damage in sepsis was evaluated.

Evaluation of the effects of pregabalin and dexamethasone coadministration on preemptive multimodal analgesia and anxiety in third molar surgeries: a triple-blind randomized clinical trial.

OBJECTIVE: To evaluate the efficacy of pregabalin and dexamethasone coadministration in preemptive analgesia and anxiety control in lower third molar surgery. MATERIALS AND METHODS: A triple-blind, split-mouth clinical trial conducted with patients divided into two groups: control group, receiving placebo and dexamethasone, and test group, receiving pregabalin and dexamethasone preoperatively. The evaluated variables were pain, measured by the Visual Analog Scale (VAS), anxiety assessed through the State-Trait Anxiety Inventory (STAI) questionnaires, hemodynamic parameters [Blood Pressure (BP), Heart Rate (HR), Oxygen Saturation (SpO2)], and sedation assessed by the Ramsay scale. RESULTS: A total of 31 patients were included. The test group exhibited a significant reduction in pain at 2,4,6,8,12,16,24, and 48 h after surgery and in the consumption of rescue analgesics. Anxiety, evaluated by STAI and VAS, showed a significant decrease in the test group (p < 0.001). Additionally, there was a significant decrease in BP at most of the assessed time points (p < 0.05) and a significant reduction in HR at two different time intervals (p = 0.003 and p = 0.009), indicating a positive effect in the test group. There was no significant difference in SpO2 between the groups. Sedation assessment revealed a significant difference at all time points favoring the test group (p < 0.05). There were no significant postoperative adverse effects. CONCLUSIONS: Pregabalin coadministered with dexamethasone demonstrated significant efficacy in controlling postoperative pain and anxiety, as well as a sedative effect. CLINICAL RELEVANCE: The coadministration of pregabalin with dexamethasone may presents potential advantages in both pain modulation and psychological well-being of individuals undergoing third molar surgeries. TRIAL REGISTRATION: Brazilian Clinical Trials Registry (REBEC), No. RBR-378h6t6.

The effect of oral pregabalin on the minimum alveolar concentration of isoflurane in cats.

OBJECTIVE: To investigate the effect of three different doses of oral pregabalin on minimum alveolar concentration of isoflurane (MACISO) in cats. STUDY DESIGN: Prospective, randomized, placebo-controlled, blinded, crossover trial. ANIMALS: A group of eight healthy adult cats aged 24-48 months. METHODS: Cats were randomly assigned to three oral doses of pregabalin (low dose: 2.5 mg kg-1, medium dose: 5 mg kg-1, high dose: 10 mg kg-1) or placebo 2 hours before MACISO determination, with the multiple treatments administered with a minimum 7 day washout period. Anesthesia was induced and maintained with isoflurane in oxygen until endotracheal intubation was achieved, and maintained with isoflurane with volume-controlled ventilation. MACISO was determined in triplicate using the bracketing technique and tail clamp method 120 minutes after pregabalin or placebo administration. Physiologic variables (including heart rate and blood pressure) recorded during MACISO determination were averaged and compared between the pregabalin and placebo treatments. One-way analysis of variance and the Friedman test were used to assess the difference for normally and non-normally distributed data, respectively. The Tukey test was used as a post hoc analysis. Values of p < 0.05 were considered significant. RESULTS: The MACISO with the medium- and high-dose pregabalin treatments were 1.33 ± 0.21% and 1.23 ± 0.17%, respectively. These were significantly lower than MACISO after placebo treatment (1.62 ± 0.13%; p = 0.014, p < 0.001, respectively), representing a decrease of 18 ± 9% and 24 ± 6%. The mean plasma pregabalin concentration was negatively correlated with MACISO values. Physiologic variables did not differ significantly between treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Doses of 5 or 10 mg kg-1 pregabalin, administered orally 2 hours before determining MACISO, had a significant isoflurane-sparing effect in cats.

Oral self-administration of pregabalin in a mouse model and the resulting drug addiction features.

Prescription drug abuse is an issue that is rapidly growing globally. Pregabalin, an anticonvulsant, analgesic, and anxiolytic medication, is effective in the management of multiple neurological disorders; however, there is increasing concern regarding its widespread illicit use. It has been previously reported in mice that pregabalin can induce conditioned place preference. In this current investigation, the potential of pregabalin to elicit free-choice drinking in a mouse model of drug addiction, and its effect on recognition and withdrawal behaviors after forced abstinence, were studied. Twenty-two male BALB/c mice were randomly divided into three groups (n = 7-8/group); control, pregabalin-30, and pregabalin-60. The study had three phases: habituation (days 1-5) with free water access, free-choice drinking (days 6-13) with pregabalin groups receiving one water and one pregabalin bottle, and forced abstinence (days 14-21) with free water access. On day 13, the first open field test was conducted, followed by the Novel Object Recognition Test. On day 21, the second open field test was performed, followed by the Tail Suspension Test and Forced Swimming Test. Pregabalin elicited voluntary drinking in the higher-dose group, concurrently causing a decline in recognition memory performance in the novel object recognition test. Moreover, pregabalin induced withdrawal behavior after a period of forced abstinence in the forced swimming and tail suspension tests. This is the first report to establish an animal model of free-choice pregabalin drinking that may be used for further molecular studies and targeted therapy for pregabalin addiction.

Efficacy of gabapentin and pregabalin for treatment of post refractive surgery pain: a systematic review and meta-analysis.

INTRODUCTION: For ophthalmic patients, eye discomfort is a major problem that requires efficient pain treatment techniques. Pregabalin and gabapentin have surfaced as viable treatments for post-refractive surgery pain. To manage pain after refractive surgery, gabapentin and pregabalin were evaluated in this systematic review and meta-analysis. METHODOLOGY: A thorough search of databases including PubMed, Embase, Cochrane Library, and CINAHL was performed until March 2024. Inclusion criteria were randomized controlled trials assessing pregabalin and/or gabapentin's effectiveness in treating pain post-PRK, LASIK, and LASEK surgeries. RESULTS: Six studies met inclusion criteria, comprising a total of 391 patients undergoing various corneal surgeries. The meta-analysis revealed that pregabalin was significantly more effective than placebo in reducing pain on the first and second postoperative days (SMD day 1: -0.32, 95% CI -0.54, -0.09; SMD day 2: -0.55, 95% CI -0.85, -0.25), while gabapentin showed significant pain reduction on the second day only (SMD day 2: -0.42, 95% CI -0.71, -0.13). Combined analysis for both medications showed significant pain reduction on the first- and second-days post-surgery. No significant increase in adverse events was associated with either medication. Publication bias was minimal except for a slight asymmetry noted on day 1 effectiveness. CONCLUSION: Pregabalin and gabapentin are effective in reducing postoperative pain following refractive surgeries, with pregabalin showing a greater effect. Both medications are safe, with no significant increase in adverse events. Further research with standardized methodologies and long-term follow-up is recommended to optimize postoperative pain management in ocular surgeries.

Understanding Long-Stay Gabapentin Use Increases: A National Nursing Home Clinician Survey on Prescribing Intent.

OBJECTIVES: Explore the indications for long-stay gabapentin use and elucidate the factors spurring the rapid increase in gabapentin prescribing in nursing homes (NHs). METHODS: National cross-sectional survey of NH prescribers distributed anonymously using SurveyMonkey. Sampling for convenience was obtained through crowdsourcing, leveraging collaborations with NH clinician organizations. Developed by a multidisciplinary team, pilot data/existing literature informed survey content. RESULTS: A total of 131 surveys completed. Participants: 71% white, 52% female, 71% physicians. Off-label gabapentin prescribing was ubiquitous. Nearly every clinician used gabapentin for neuropathic pain, most for any form of pain. Many clinicians also prescribe gabapentin to moderate psychiatric symptoms and behaviors. Clinicians' prescribing was influenced by opioid, antipsychotic, and anxiolytic reduction policies because gabapentin was perceived as an unmonitored and safer alternative. CONCLUSIONS: Off-label gabapentin increases are closely linked to opioid reduction efforts as more NH clinicians utilize gabapentin as an unmonitored opioid alternative. Our results highlight, however, the less recognized significance of long-stay prescribing for psychiatric symptoms and the similar contribution of psychotropic reduction initiatives, a phenomenon warranting further scrutiny. CLINICAL IMPLICATIONS: Clinicians perceive gabapentin as safer than the drugs it is replacing. Whether this is true remains unclear; the individual- and population-level risks of increased gabapentin use are largely unknown.