Gabapentin for Postoperative Pain Control and Opioid Reduction in Scrotal Surgery: A Randomized Controlled Clinical Trial.

PURPOSE: To assess the safety and efficacy of gabapentin in reducing postoperative pain among patients undergoing scrotal surgery for male infertility by conducting a randomized, double-blind, placebo-controlled trial. MATERIALS AND METHODS: In this randomized, double-blind, placebo-controlled trial, healthy men undergoing scrotal surgery with a single surgeon were randomized to receive either (1) gabapentin 600 mg given 2 hours preoperatively and 300 mg taken 3 times a day postoperatively for 3 days, or (2) inactive placebo. The primary outcome measure was difference in postoperative pain scores. Secondary outcomes included differences in opioid usage, patient satisfaction, and adverse events. RESULTS: Of 97 patients screened, 74 enrolled and underwent randomization. Of these, 4 men were lost to follow-up, and 70 were included in the final analysis (35 gabapentin, 35 placebo). Both differences in initial postoperative mean pain score (-1.14, 95% CI -2.21 to -0.08, P = .035) and final mean pain score differences (-1.27, 95% CI -2.23 to -0.32, P = .0097) indicated lower gabapentin pain compared to placebo. There were no statistically significant differences in opioid usage, patient satisfaction, or adverse events. CONCLUSIONS: These data suggest that perioperative gabapentin results in a statistically and clinically significant decrease in pain following scrotal surgery. While there was no evidence of an impact on opioid usage or patient satisfaction, given the low risk of adverse events, it may be considered as part of a multimodal pain management strategy.

Gabapentin attenuates cardiac remodeling after myocardial infarction by inhibiting M1 macrophage polarization through the peroxisome proliferator-activated receptor-γ pathway.

OBJECTIVES: Inflammation regulates ventricular remodeling after myocardial infarction (MI), and gabapentin exerts anti-inflammatory effects. We investigated the anti-inflammatory role and mechanism of gabapentin after MI. METHODS: Rats were divided into the sham group (n = 12), MI group (n = 20), and MI + gabapentin group (n = 16). MI was induced by left coronary artery ligation. The effects of gabapentin on THP-1-derived macrophages were examined in vitro. RESULTS: In vivo, 1 week after MI, gabapentin significantly reduced inducible nitric oxide synthase (iNOS; M1 macrophage marker) expression and decreased pro-inflammatory factors (tumor necrosis factor [TNF]-α and interleukin [IL]-1ß). Gabapentin upregulated the M2 macrophage marker arginase-1, as well as CD163 expression, and increased the expression of anti-inflammatory factors, including chitinase-like 3, IL-10, and transforming growth factor-ß. Four weeks after MI, cardiac function, infarct size, and cardiac fibrosis improved after gabapentin treatment. Gabapentin inhibited sympathetic nerve activity and decreased ventricular electrical instability in rats after MI. Tyrosine hydroxylase and growth-associated protein 43 were suppressed after gabapentin treatment. Gabapentin downregulated nerve growth factor (NGF) and reduced pro-inflammatory factors (iNOS, TNF-α, and IL-1ß). In vitro, gabapentin reduced NGF, iNOS, TNF-α, and IL-1ß expression in lipopolysaccharide-stimulated macrophages. Mechanistic studies revealed that the peroxisome proliferator-activated receptor-γ antagonist GW9662 attenuated the effects of gabapentin. Moreover, gabapentin reduced α2δ1 expression in the macrophage plasma membrane and reduced the calcium content of macrophages. CONCLUSION: Gabapentin attenuates cardiac remodeling by inhibiting inflammation via peroxisome proliferator-activated receptor-γ activation and preventing calcium overload.

An experimental model for primary neuropathic corneal pain induced by long ciliary nerve ligation in rats.

ABSTRACT: Neuropathic corneal pain (NCP) is a new and ill-defined disease characterized by pain, discomfort, aching, burning sensation, irritation, dryness, and grittiness. However, the mechanism underlying NCP remain unclear. Here, we reported a novel rat model of primary NCP induced by long ciliary nerve (LCN) ligation. After sustained LCN ligation, the rats developed increased corneal mechanical and chemical sensitivity, spontaneous blinking, and photophobia, which were ameliorated by intraperitoneal injection of morphine or gabapentin. However, neither tear reduction nor corneal injury was observed in LCN-ligated rats. Furthermore, after LCN ligation, the rats displayed a significant reduction in corneal nerve density, as well as increased tortuosity and beading nerve ending. Long ciliary nerve ligation also notably elevated corneal responsiveness under resting or menthol-stimulated conditions. At a cellular level, we observed that LCN ligation increased calcitonin gene-related peptide (neuropeptide)-positive cells in the trigeminal ganglion (TG). At a molecular level, upregulated mRNA levels of ion channels Piezo2, TRPM8, and TRPV1, as well as inflammatory factors TNF-α, IL-1ß, and IL-6, were also detected in the TG after LCN ligation. Meanwhile, consecutive oral gabapentin attenuated LCN ligation-induced corneal hyperalgesia and increased levels of ion channels and inflammation factors in TG. This study provides a reliable primary NCP model induced by LCN ligation in rats using a simple, minimally invasive surgery technique, which may help shed light on the underlying cellular and molecular bases of NCP and aid in developing a new treatment for the disease.

Characterizing Opioid Prescribing Trends of Medical Oncologists From 2013 to 2019: Analysis From the Centers for Medicare & Medicaid Services Medicare Part D Prescribers Database.

PURPOSE: Opioid prescribing trends in medical oncology are poorly defined past 2017, the year after the CDC updated opioid prescription guidelines in noncancer settings. We aim to characterize pain management by medical oncologists by analyzing opioid and gabapentin prescribing trends from 2013 to 2019, identify physician-related factors associated with prescribing patterns, and assess whether CDC guidelines for nononcologic settings changed prescribing patterns. METHODS: The Centers for Medicare & Medicaid Services (CMS) Medicare Part D Prescribers-by Provider, CMS Medicare Part D Prescribers-by Provider and Drug, and CMS Medicare Physician National Downloadable files from 2013 to 2019 were merged by National Provider Identification. The database included physicians' sex, years of practice, regions, and practice settings. Multivariable binary logistic regression identified significant predictors of total opioid, long-acting opioid, and gabapentin prescriptions. RESULTS: Binary logistic regression modeling revealed no significant difference in mean daily total opioid prescriptions from 2013 to 2017. Daily opioid prescriptions by medical oncologists decreased significantly after 2017 (P < .001). Increased opioid prescribing was associated with physician male sex (P < .001), practicing over 10 years (P < .001), and practice in nonurban areas (P < .001). Opioid prescribing was greatest in the South and Midwest United States (P < .001). The same patterns were observed with total long-acting opioid prescriptions, whereas gabapentin prescribing increased from 2013 to 2019 (P < .001). CONCLUSION: Opioid prescriptions by medical oncologists decreased significantly from 2013 to 2019, but this decrease was most substantial from 2017 to 2019. These results may imply that the 2016 CDC guidelines influenced medical oncologists, particularly more junior physicians in urban settings, to manage chronic cancer pain with alternative therapies.

Can gabapentinoids decrease perioperative opioid requirements in orthopaedic trauma patients? A single-centre retrospective analysis.

INTRODUCTION: Perioperative pain control in patients with orthopaedic trauma/extremity fractures has gained a lot of attraction from the scientific community in the last two decades. In addition to multimodal analgesia, the use of non-opioid drugs like gabapentinoids for pain relief is gradually finding its place in several orthopaedic subspecialties like spinal surgery, arthroplasty, and arthroscopic procedures. We envisage investigating the effectiveness of gabapentin in perioperative pain control in patients with extremity fractures undergoing surgical fixation. METHODOLOGY: This was a retrospective comparative study conducted between January 2020 and January 2022. Patients with isolated fractures of the extremity involving long bones who were treated at our trauma centre, during the study period were divided into two groups based on the analgesics they received. Patients who received gabapentin and paracetamol were placed in group GP and those who received only paracetamol were assigned group NGP. Gabapentin was given in a single dose of 300 mg 4 h before surgery. Postoperatively, they were given 300 mg 12 hourly for 2 days. All patients in our trauma centre are usually managed with parenteral paracetamol administration pre and postoperatively. VAS score was calculated postoperatively at 2, 6, 12, 24 and 48 h. Patients requiring additional analgesics for pain relief were administered intravenous tramadol or a buprenorphine patch was applied. Patients in both groups were compared in terms of pain control, the additional requirement of opioid analgesics, and any adverse event related to medications. RESULTS: One hundred and nineteen patients were enrolled in the study. Out of 65 patients in the NGP group (non-gabapentin group), 74% of patients received additional opioid analgesics apart from paracetamol. Out of the 54 patients in the GP group (gabapentin group), only 41% required additional opioid analgesia for pain control. There was a significant difference in opioid consumption between the two groups (p < 0.01). VAS scores were not significantly different between the two groups at 2, 4, 6, 12, 24 and 48 h. Gender and fracture morphology did not affect opioid intake in the GP group. However, in the non-gabapentin group, there was a significant difference in opioid requirement in patients with intraarticular fractures (p < 0.01). CONCLUSION: Analgesic requirements vary from patient to patient depending on the injury's severity and surgery duration. However, there are no strict guidelines for pain relief in limb trauma surgeries which often leads to overuse and opioid-related complications or underuse and chronic pain. Gabapentinoids can supplement the analgesic effect of paracetamol in trauma patients during the perioperative period, decreasing the need for opioids.

Effects of Gabapentin on Postoperative Pain and Opioid Consumption Following Laparoscopic Cholecystectomy: A Systematic Review and Meta-analysis.

PURPOSE: Examine the efficacy of gabapentin on postoperative pain scores and opioid consumption in laparoscopic cholecystectomy. DESIGN: Systematic review and meta-analysis. METHODS: PubMed, EBSCO, CINAHL, the Cochrane Central Register of Controlled Trials, Google Scholar, and gray literature was used to search the literature. Only randomized controlled trials were included. Outcomes were reported using the risk ratio and mean difference (MD). Risk of bias and the grades of recommendation, assessment, development, and evaluation (GRADE) system was used to the assessed quality of evidence. FINDINGS: Nineteen trials involving 2,068 patients were analyzed. Compared to placebo, gabapentin reduced the cumulative pain scores in the first 24 hours after surgery (MD, -1.19; 95% CI, -1.39-0.99; P < .00011), opioid consumption (MD, -3.51; 95% CI, -4.67 to -2.35; P < .00001), and the incidence of postoperative nausea and vomiting (risk ratio, 0.64; 95% CI, 0.52-0.78; P < .00001) with prolonged time to first analgesic rescue (MD, 210.9; 95% CI, 76.90-344.91; P = .002). However, gabapentin has little to no effect on the incidence of sedation, somnolence, and respiratory depression. CONCLUSIONS: Gabapentin can be added as part of the multimodal pain management for patients undergoing laparoscopic cholecystectomy. Extrapolation of these findings to clinical settings must take into consideration the limitations identified in this review.

Gabapentin for Pain in Pediatric Palliative Care.

OBJECTIVE: Gabapentin is commonly used to treat pain in children receiving pediatric palliative care. This study describes the real-world use of gabapentin and the associated benefits and adverse effects/events (AEs). METHODS: A prospective, multicenter cohort of standardized data collection after a clinical decision was made to use gabapentin for managing neuropathic or nociplastic pain in children attended on by a pediatric palliative care service. It was conducted across 11 sites in seven countries including hospital, inpatient, and outpatient services. Clinical outcomes were graded using pain scales validated for age and cognitive ability and the National Cancer Institute Common Terminology Criteria for Adverse Events (NCICTCAE) at baseline, 14 days, 28 days, six weeks and 12 weeks after initiation of gabapentin. Ad-hoc safety reporting continued throughout the study. RESULTS: Data were collected from 127 children with a median age of 4.7 years (IQR 0.1-17.9); 61% had a neurological disorder, 21% advanced cancer and the cohort had a high level of disability (Lansky/Karnofsky performance score 37.1). Gabapentin was prescribed at standard pediatric doses. On average, 76% of children had a reduction in pain and 42% experienced a potential AE. The mean pain score decreased from 6.0 (SD 2.6) at baseline to 3.3 (SD 2.4) at 14 days and 1.8 (SD 1.8) after 12-weeks of gabapentin therapy. Ten percent had increased pain at each time point. AEs did not increase when individual changes over time were accounted for except for somnolence (7%). Serious AEs attributable to gabapentin were possible or probable in 3% of children. CONCLUSIONS: Gabapentin prescribed at standard doses for advanced cancer and severe neurological injury in children under a pediatric palliative care service was associated with generally improved pain intensity at previously described levels of adverse effects.

Eliminating the benzos: A benzodiazepine-sparing approach to preventing and treating alcohol withdrawal syndrome.

BACKGROUND: Alcohol withdrawal syndrome (AWS) represents significant cost to the hospitalized trauma population from a clinical and financial perspective. Historically, AWS has been managed with benzodiazepines. Despite their efficacy, benzodiazepines carry a heavy adverse effect profile. Recently, benzodiazepine-sparing protocols for the prophylaxis and treatment of AWS have been used in medical patient populations. Most existing benzodiazepine-sparing protocols use phenobarbital, while ours primarily uses gabapentin and clonidine, and no such protocol has been developed and examined for safety and efficacy specifically within a trauma population. METHODS: In December of 2019, we implemented our benzodiazepine-sparing protocol for trauma patients identified at risk for alcohol withdrawal on admission. Trauma patients at risk for AWS admitted to an academic Level 1 trauma center before (conventional) and after (benzodiazepine-sparing [BS]) protocol implementation were compared. Outcomes examined include morphine milligram equivalent dosing rates and lorazepam equivalent dosing rates as well as the Clinical Institute Withdrawal Assessment for Alcohol, revised (CIWA-Ar) scores, hospital length of stay, intensive care unit length of stay, and ventilator days. RESULTS: A total of 387 conventional and 134 benzodiazepine sparing patients were compared. Injury Severity Score (13 vs. 16, p = 0.10) and admission alcohol levels (99 vs. 149, p = 0.06) were similar. Patients in the BS pathway had a lower maximum daily CIWA-Ar (2.7 vs. 1.5, p = 0.04). While mean morphine milligram equivalent per day was not different between groups (31.5 vs. 33.6, p = 0.49), mean lorazepam equivalents per day was significantly lower in the BS group (1.1 vs. 0.2, p < 0.01). Length of stay and vent days were not different between the groups. CONCLUSION: Implementation of a benzodiazepine-sparing pathway that uses primarily clonidine and gabapentin to prevent and treat alcohol withdrawal syndrome in trauma patients is safe, reduces the daily maximum CIWA-Ar, and significantly decreases the need for benzodiazepines. Future studies will focus on outcomes affected by avoiding AWS and benzodiazepines in the trauma population. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

The impact of novel inflammation-preserving treatment towards lumbar disc herniation resorption in symptomatic patients: a prospective, multi-imaging and clinical outcomes study.

PURPOSE: We performed a prospective one-year multi-imaging study to assess the clinical outcomes and rate of disc resorption in acute lumbar disc herniation (LDH) patients undergoing inflammation-preserving treatment (i.e. no NSAIDS, steroids). METHODS: All patients received gabapentin to relieve leg pain, 12 sessions of acupuncture. Repeat MRI was performed, every 3 months, after 12 sessions of treatment continued for those without 40% reduction in herniated disc sagittal area. Disc herniations sizes were measured on sagittal T2W MRI sequences, pre-treatment and at post-treatment intervals. Patients were stratified to fast, medium, slow, and prolonged recovery groups in relation to symptom resolution and disc resorption. RESULTS: Ninety patients (51% females; mean age: 48.6 years) were assessed. Mean size of disc herniation was 119.54 ± 54.34 mm2, and the mean VAS-Leg score was 6.12 ± 1.13 at initial presentation. A total of 19 patients (21.1%) improved at the time of the repeat MRI (i.e. within first 3 months post-treatment). 100% of all patient had LDH resorption within one year (mean: 4.4. months). There was no significant difference at baseline LDH between fast, medium, slow, and prolonged resorption groups. Initial LDH size was weakly associated with degree of leg pain at baseline and initial gabapentin levels. Surgery was avoided in all cases. CONCLUSION: This is the first study to note inflammation-preserving treatment, without conventional anti-inflammatory and steroid medications, as safe and effective for patients with an acute LDH. Rate of disc resorption (100%) was higher than comparative recent meta-analysis findings (66.7%) and no patient underwent surgery.

Gabapentin and postoperative pain and opioid consumption: A double-blind randomized controlled trial of perioperative pain management for sinus surgery.

BACKGROUND: The link between post-operative narcotic prescription and opioid misuse has spurred a nationwide effort to reduce perioperative opioid use. Previous work has suggested that perioperative gabapentin may reduce post-operative pain and opioid consumption across different procedures, although the optimal regimen remains to be defined. METHODS: Chronic rhinosinusitis (CRS) patients undergoing functional endoscopic sinus surgery (FESS) with or without septoplasty were randomized to receive a 7-day pre- and post-operative course of placebo or gabapentin, starting at 300 mg daily and titrated to 300 mg three times daily, in a double-blind fashion. Primary endpoint was pain level using a validated visual analog scale (VAS). Secondary endpoints included post-operative opioid consumption and side effects, as well as modified Lund-Kennedy endoscopy, Lund-Mackay, and SNOT-22 scores. RESULTS: Analysis of 35 patients (20 gabapentin, 15 control) showed no significant difference in mean postoperative VAS (p = 0.18) or postoperative opioid consumption between the placebo and gabapentin groups (2.3 and 4.8 oxycodone tablets respectively, p = 0.18). 15 of 35 patients did not require any post-operative oxycodone tablets, and only two patients required more than six tablets. CONCLUSION: Preliminary results show no significant change in pain after FESS with or without septoplasty in patients taking 7-day pre- and post-operative gabapentin versus placebo. Results also showed no significant difference in opioid consumption between the treatment and placebo groups. Post-operative pain scores and opioid requirements are both quite low following FESS. Many patients do not need opioids at all, suggesting that routine initial post-operative opioid prescriptions can be limited accordingly.

[Efficacy and safety of pulsed radiofrequency combined with gabapentin in the treatment of acute herpetic neuralgia].

Objective: To explore the clinical efficacy and safety of pulsed radiofrequency (PRF) combined with gabapentin in the treatment of acute herpetic neuralgia (AHN). Methods: A total of 123 AHN patients were retrospectively selected in Henan Provincial People's Hospital from November 2019 to July 2022, who were divided into two groups based on treatment methods: control group (treated with gabapentin, n=61) and study group (treated with gabapentin and PRF, n=62). The visual analog scale (VAS) was utilized for pain severity assessment and the self-rating scale for sleep (SRSS) was utilized for sleep quality evaluation. The differences in serum levels of interleukin (IL)-10, chemokine ligand 10 (CXCL-10), prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), IL-2 and IL-6 before and after treatment were compared between the two groups. The overall treatment effectiveness and the occurrence rates of postherpetic neuralgia and adverse reactions were evaluated in both groups. Results: Among the study group patients, 28 were male and 34 were female, and the age was (62.8±8.5) years. Among the control group patients, 35 were male and 26 were female, and the age was (64.0±7.8) years. The VAS scores of the study group before and after treatment were 7.96±1.33 and 1.52±0.60, respectively, while the control group were 7.68±1.52 and 2.70±0.64. The SRSS scores before and after treatment in the study group were 31.74±5.90 and 12.06±2.81, respectively, while those in the control group were 33.10±5.54 and 14.14±2.96, respectively. Before treatment, there were no statistically differences of the VAS scores and SRSS scores in both groups (all P>0.05). After treatment, the VAS scores and SRSS scores in both groups decreased compared with before treatment (all P<0.05), the study group's VAS scores and SRSS scores were lower than those in the control group (all P<0.05). Before treatment, there were no statistically differences of the serum levels of IL-10, CXCL-10, PGE2, COX-2, IL-2 and IL-6 in both groups (all P>0.05). After treatment, the serum levels of IL-10, CXCL-10, PGE2, COX-2 and IL-6 in both groups decreased compared with before treatment, while the IL-2 level increased. Additionally, the study group had lower serum levels of IL-10, PGE2, COX-2 and IL-6 compared with the control group (all P<0.05). After treatment, the study group had 35 cases of cure, 26 cases of effectiveness, and 1 case of ineffectiveness, while the control group had 22 cases of cure, 31 cases of effectiveness, and 8 cases of ineffectiveness. The overall treatment efficacy of the study group was better than that of the control group (P=0.012). The incidence of postherpetic neuralgia in the study group after treatment was 16.1% (10/62), which was lower than that in the control group, which was 37.7% (23/61) (P<0.05). There were no statistically differences of the occurrence rates of adverse reactions in both groups (all P>0.05). Conclusion: Combining PRF with gabapentin for the treatment of AHN demonstrates better overall efficacy and safety, which can more effectively alleviate pain, improve sleep, and reduce inflammatory cytokine levels.

[Metformin alleviates pathologic pain in mice with radiation dermatitis by inhibiting p38MAPK/NF-κB signaling pathway].

OBJECTIVE: To observe the therapeutic effect of metformin on pathological pain in mice with radiation dermatitis and explore the underlying mechanism. METHODS: Thirty-two male adult ICR mice were randomized into normal control group, radiation dermatitis model group, metformin treatment (200 mg/kg) group and gabapentin (100 mg/kg) group (n=8).In the latter two groups, metformin treatment was administered after modeling via intraperitoneal injection and gabapentin by gavage on a daily basis for 16 days; the mice in the control group and model group received intraperitoneal injection of normal saline.After the last administration, radiation dermatitis was graded in each group.Mechanical withdraw threshold (MWT) and thermal withdrawal latency (TWL) of the mice were tested one day before and at 1, 4, 8, 12 and 16 days after modeling.Western blotting was used to measure the protein expression levels of p38MAPK, p-p38MAPK, NF-κB p65 and p-NF-κB p65 in the L4-L6 spinal cord, and the concentrations of IL-1ß, IL-6 and TNF-α in the spinal cord tissue were determined with ELISA. RESULTS: Compared with those in the control group, the mice in the other 3 groups showed obvious symptoms of radiation dermatitis after modeling (P<0.05), which were significantly alleviated by treatment with metformin (P<0.05).The mice in the model group exhibited significant decreases in MWT and TWL (P<0.05), which were improved by treatment with metformin and gabapentin (P<0.05).Compared with those in the model group, the levels of p-p38MAPK, p-NF-κB p65, IL-1ß, IL-6 and TNF-α in the spinal cord were significantly decreased in the mice after metformin treatment (P<0.05). CONCLUSION: Metformin can significantly ameliorate pathological pain symptoms in mice with radiation dermatitis possibly by inhibiting the activation of p38MAPK/NF-κB signaling pathway.

Effects of Gabapentin on Emergence Delirium in Pediatric Tonsillectomy/Adenoidectomy Patients: A Post-Hoc Analysis.

Emergence delirium (ED) is a significant source of both short- and long-term negative effects in the postoperative pediatric population, most notably following otolaryngology surgeries with an occurrence rate of 17.9%. Gabapentin, a gamma aminobutyric acid agonist, has been used for enhanced recovery in adult patients and for the purpose of decreasing ED in some pediatric patients undergoing strabismus surgery. This secondary analysis examined the effects of preoperative administration of gabapentin on the reduction of postoperative ED in pediatric patients between the ages of 3-18 undergoing elective tonsillectomy and adenoidectomy. The parent study randomized subjects to receive preoperative gabapentin vs placebo. Our chart review encompassed both objective and subjective measures to identify the incidence of ED. While we found no statistical significance between the treatment and control groups, there was a clinically significant reduction of ED behaviors in the gabapentin group. The limitations included nonstandardized intraoperative medication administration, small sample size, and the lack of a validated tool for documenting behaviors associated with ED in the immediate postoperative period. Based on the results of this analysis, further investigation is warranted into the potential benefit of gabapentin to reduce the incidence of postoperative ED in the pediatric patient.

Efficacy of Gabapentin For Post-COVID-19 Olfactory Dysfunction: The GRACE Randomized Clinical Trial.

Importance: The COVID-19 pandemic affected millions of people and has become a dominant etiology of olfactory dysfunction (OD). No interventions with definitive clinical utility exist. Gabapentin represents a potential therapy for COVID-19-induced OD. Objective: To evaluate the efficacy of oral gabapentin on olfactory function and olfaction-related quality of life in patients with COVID-19-induced OD. Design, Setting, and Participants: This pilot double-blinded, placebo-controlled randomized clinical trial (RCT) was conducted at Washington University School of Medicine in St Louis from January 7, 2022, to February 3, 2023. Adults with at least 3 months of OD after COVID-19 infection were eligible for inclusion. Participants with a history of other causes of OD or contraindications to gabapentin were excluded. Intervention: Patients were randomized 1:1 to oral gabapentin or placebo. All patients underwent titration to a maximum tolerable dose, which was maintained during an 8-week fixed-dose (FD) phase then tapered off. Participants were monitored for 4 weeks following cessation of study medication. Main Outcomes and Measures: Outcomes were assessed following the 8-week FD phase and 4 weeks after taper completion. The primary outcome measure was the response rate determined by subjective improvement in OD on the Clinical Global Impression of Improvement (CGI-I) after the FD phase. Other subjective and objective measures of olfactory function were also assessed as secondary outcome measures. Results: Sixty-eight participants were enrolled (34 randomized to each arm), a total of 44 participants completed the FD period and 20 (45.4%) reported response to treatment with at least slight improvement in olfaction from baseline. Of those randomized, 51 (75%) were women and 56 were White (82%) with a mean (SD) age of 43 (13.5) years. Baseline demographic features including age, sex, and race and ethnicity were not significantly different between the groups. Of the 18 participants in the gabapentin group, 8 (44%) were responders and of the 26 participants in the placebo group, 12 (46%) reported response to treatment (percent difference, 1.7%; 95% CI, -31.6% to 28.2%). Mixed-model analysis of all secondary outcome measures demonstrated no clinically meaningful or statistically significant difference between the gabapentin and placebo groups throughout the trial. There were no serious adverse events. Conclusions and Relevance: In this randomized clinical trial, gabapentin was not associated with statistically significant or clinically meaningful benefit over placebo and likely is not an efficacious therapy for COVID-19-induced OD. Trial Registration: ClinicalTrials.gov Identifier: NCT05184192.

Different Gabapentin and Pregabalin Dosages for Perioperative Pain Control in Patients Undergoing Spine Surgery: A Systematic Review and Network Meta-Analysis.

IMPORTANCE: Patients undergoing spine surgery often experience severe pain. The optimal dosage of pregabalin and gabapentin for pain control and safety in these patients has not been well established. OBJECTIVE: To evaluate the associations of pain, opioid consumption, and adverse events with different dosages of pregabalin and gabapentin in patients undergoing spine surgery. DATA SOURCES: PubMed/MEDLINE, Embase, Web of Science, Cochrane library, and Scopus databases were searched for articles until August 7, 2021. STUDY SELECTION: Randomized clinical trials conducted among patients who received pregabalin or gabapentin while undergoing spine surgery were included. DATA EXTRACTION AND SYNTHESIS: Two investigators independently performed data extraction following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) reporting guideline. The network meta-analysis was conducted from August 2022 to February 2023 using a random-effects model. MAIN OUTCOMES AND MEASURES: The primary outcome was pain intensity measured using the Visual Analog Scale (VAS), and secondary outcomes included opioid consumption and adverse events. RESULTS: Twenty-seven randomized clinical trials with 1861 patients (median age, 45.99 years [range, 20.00-70.00 years]; 759 women [40.8%]) were included in the systematic review and network meta-analysis. Compared with placebo, the VAS pain score was lowest with gabapentin 900 mg per day, followed by gabapentin 1200 mg per day, gabapentin 600 mg per day, gabapentin 300 mg per day, pregabalin 300 mg per day, pregabalin 150 mg per day, and pregabalin 75 mg per day. Additionally, gabapentin 900 mg per day was found to be associated with the lowest opioid consumption among all dosages of gabapentin and pregabalin, with a mean difference of -22.07% (95% CI, -33.22% to -10.92%) for the surface under the cumulative ranking curve compared with placebo. There was no statistically significant difference in adverse events (nausea, vomiting, and dizziness) among all treatments. No substantial inconsistency between direct and indirect evidence was detected for all outcomes. CONCLUSIONS AND RELEVANCE: These findings suggest that gabapentin 900 mg per day before spine surgery is associated with the lowest VAS pain score among all dosages. In addition, no differences in adverse events were noted among all treatments.

Effect of gabapentin on ambulatory, direct, systemic arterial blood pressure in apparently healthy cats in the at-home and in-clinic environments.

OBJECTIVES: Situational increases in blood pressure (BP) frequently confound the accurate diagnosis of pathological systemic hypertension in cats. The objective of this study was to investigate the effect of gabapentin on direct, ambulatory systolic arterial BP (SBP) in cats in at-home and in-clinic environments. METHODS: Six adult purpose-bred cats with surgically implanted femoral artery telemetric BP-sensing catheters were administered 100 mg of gabapentin or a placebo orally in two randomized, masked, crossover study phases. In the first, direct BP was measured continuously in undisturbed cats for 24 h before (at-home baseline) and 4 h after administration of study drug. The mean SBP after administration of the drug was compared between treatments. In the second study period, cats were administered gabapentin or placebo 90 mins before transport to a clinic, where direct BP was measured continuously during a simulated veterinary visit that included an indirect BP measurement session. Changes in mean direct SBP relative to the 24-h at-home pre-treatment period were calculated for each of one waiting room and two examination-room periods, and compared between treatments. Concurrent in-clinic direct and indirect SBP measurements were compared within-cat. Data were compared using linear mixed models. RESULTS: Direct SBP data from one cat were excluded due to implant failure. There were no differences in at-home or in-clinic SBP between treatment groups, with large inter-individual variability. Cats in both treatment groups experienced in-clinic increases in direct SBP relative to at-home baseline (range 11-50 and 10-52 mmHg in placebo- and gabapentin-treated cats, respectively). Across all visits, direct SBP was 15.6 mmHg higher than indirect SBP (P <0.001). No effects of treatment on difference between direct and indirect SBP were identified. CONCLUSIONS AND RELEVANCE: Significant effects of gabapentin on direct SBP were not identified, though a type II error is possible. Situational increases cannot be excluded in gabapentin-treated cats with high SBP.

Abuse and addiction in gabapentinoid drug users for neuropathic pain.

OBJECTIVE: Gabapentinoids are gamma-aminobutyric acid analogue agents used in the treatment of neuropathic pain. They are increasingly being abused to achieve euphoric and dissociative effects. This study aimed to determine drug misuse/abuse and related factors in patients who used gabapentinoids for neuropathic pain. PATIENTS AND METHODS: This study included 140 patients over the age of 18. Patients were excluded from the study if they had aphasia, dementia, or diseases that led to aphasia or cooperative and cognitive dysfunction. They were also excluded if they lacked sufficient information about how long or at what dosage they had been using the drug. The Beck Depression Inventory and Beck Anxiety Inventory were used to evaluate depression and anxiety states. The patients' levels of drug abuse were determined according to the definitions provided in the terminology for misuse, abuse, and related events. RESULTS: The mean age of the patients was 56.78 ± 14.45 years, and 52.1% of them were females. While 57.9% of the patients used pregabalin, 42.1% of the patients used gabapentin. For the median (min-max) of the dataset, the pregabalin dose was 300 (50-600) mg/day, and the gabapentin dose was 900 (300-2,400) mg/day. Abuse was present in 17.9% of the patients. Risk factors for gabapentinoid abuse were smoking, alcohol, and antidepressant use, anxiety and depression, living alone, and drug dose and duration of use. CONCLUSIONS: Before prescribing drugs and managing the treatment process in a controlled manner, questioning patients about their risk factors can reduce the rate of abuse.

Prevalence of opioid and nonopioid pain management therapies among Medicare beneficiaries with musculoskeletal pain conditions from 2016 to 2019.

INTRODUCTION: Pain treatment guidelines prioritize nonopioid therapies over opioid medications to prevent opioid-related harms. We examined trends in receipt and intensity of nonpharmacologic, nonopioid medication, and opioid therapies among Medicare beneficiaries. METHODS: Using a 20% national random sample of Medicare data from 2016 to 2019, we identified fee-for-service beneficiaries with ≥2 diagnoses of back, neck, fibromyalgia, or osteoarthritis/joint pain annually. We excluded beneficiaries with cancer. We calculated annual proportions of beneficiaries who received physical therapy (PT), chiropractic care, gabapentin, and opioids, overall and in demographic, geographic, and clinical subgroups. We estimated the intensity of therapies using the annual number of visitsor prescription fills, prescription days' supply, and opioid dose. RESULTS: During 2016-2019, PT receipt increased (22.8% to 25.5%) and the mean number of visits among recipients of PT went from 12 to 13. Chiropractic receipt (~18%) and mean annual visits (~10) remained unchanged. The prevalence of gabapentin receipt was stable at ~22% and the mean annual number of fills was unchanged though gabapentin days increased slightly. Opioid prescribing decreased (56.7% to 46.5%) and reductions in opioid dose and duration were observed. Opioid receipt was high among beneficiaries who were under 65 years, American Indian/Alaska Native, Black/African American, or had opioid use disorder (OUD), in whom nonpharmacologic therapies were also received the least. CONCLUSION: Utilization of nonopioid therapies lagged opioids among Medicare beneficiaries with musculoskeletal pain, with limited changes from 2016 to 2019. As opioid prescribing declines and alternative pain therapy receipt remains low, there are potential increasing risks of pain going untreated or undertreated and individuals seeking illicit opioids to alleviate their pain.

Opioid-Sparing Pain Control after Rhinoplasty: Updated Review of the Literature.

Rhinoplasty is one of the most performed elective surgeries, and given the opioid crisis, increasing research and studies are focused on successful pain control with multimodality opioid-sparing techniques, such as acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), and gabapentin. Although limiting overuse of opioids is critical, this cannot be at the expense of inadequate pain control, particularly as insufficient pain control can be correlated with patient dissatisfaction and the postoperative experience in elective surgery. There is likely significant opioid overprescription, as patients often report taking less than 50% of their prescribed opioids. Furthermore, excess opioids provide opportunities for misuse and opioid diversion if not disposed of properly. To optimize postoperative pain control and minimize opioid requirements, interventions must occur at the preoperative, intraoperative, and postoperative time points. Preoperative counseling is imperative to set expectations for pain and to screen for predisposing factors for opioid misuse. Intraoperatively, use of local nerve blocks and long-acting analgesia in conjunction with modified surgical techniques can lead to prolonged pain control. Postoperatively, pain should be managed with a multimodal approach, incorporating acetaminophen, NSAIDs, and potentially gabapentin with opioids reserved for rescue analgesia. Rhinoplasty represents a category of short-stay, low/medium pain, and elective procedures highly susceptible to overprescription and consequently, are readily amenable to opioid minimization through standardized perioperative interventions. Recent literature on regimens and interventions to help limit opioids after rhinoplasty are reviewed and discussed here.

Pharmacologic Management of Cancer-Related Pain in Pregnant Patients.

Despite being an essential part of whole-person care, patients with cancer often experience complex and under-treated pain. Managing cancer-related pain in patients who are also pregnant compounds the challenge for adequate pain management, as studies have largely excluded this population. Therapy for pain management should be guided by the cause and mechanism of pain. The objective of this review is to provide clinicians with an understanding of pain experienced by pregnant patients with cancer and medications that may be used to help manage cancer-related pain. Nociceptive pain results from damage to somatic or visceral tissues that may be directly caused by cancer. This type of pain can be managed in pregnant patients using acetaminophen and/or nonsteroidal antiinflammatory drugs as first-line agents. In nociceptive pain not managed by non-opioid analgesics, buprenorphine is recommended for those requiring chronic opioids to help manage their pain. Neuropathic pain that results from damage to the peripheral or central nervous system may also be directly caused by cancer, particularly chemotherapy. In pregnant patients, duloxetine and gabapentin should be considered first. Venlafaxine, pregabalin, tricyclic antidepressants, and sodium channel blockers should be avoided, if possible. Nociplastic pain is not directly caused by cancer but may be caused by ongoing peripheral nociceptive input or a condition that predates the cancer diagnosis. Duloxetine and gabapentin are reasonable agents to consider for treatment of nociceptive pain in pregnant patients. Cyclobenzaprine may also be helpful for nociplastic pain.