Benzodiazepines and their antagonists interfere with opioid-dependent stress-induced analgesia

The Perioperative Use of Benzodiazepines for Major Orthopedic Surgery in the United States

BACKGROUND

Despite numerous indications for perioperative benzodiazepine use, associated risks may be exacerbated in elderly and comorbid patients. In the absence of national utilization data, we aimed to describe utilization patterns using national claims data from total hip/knee arthroplasty patients (THA/TKA), an increasingly older and vulnerable surgical population.

METHODS

We included data on 1,863,996 TKAs and 985,471 THAs (Premier Healthcare claims data, 2006-2019). Benzodiazepine utilization (stratified by long- and short-acting agents) was assessed by patient- and health care characteristics, and analgesic regimens. Given the large sample size, standardized differences instead of P values were utilized to signify meaningful differences between groups (defined by value >0.1).

RESULTS

Among 1,863,996 TKA and 985,471 THA patients, the utilization rate of benzodiazepines was 80.5% and 76.1%, respectively. In TKA, 72.6% received short-acting benzodiazepines, while 7.9% received long-acting benzodiazepines, utilization rates 68.4% and 7.7% in THA, respectively. Benzodiazepine use was particularly more frequent among younger patients (median age [interquartile range {IQR}]: 66 [60-73]/64 [57-71] among short/long-acting compared to 69 [61-76] among nonusers), White patients (80.6%/85.4% short/long-acting versus 75.7% among nonusers), commercial insurance (36.5%/34.0% short/long-acting versus 29.1% among nonusers), patients receiving neuraxial anesthesia (56.9%/56.5% short/long-acting versus 51.5% among nonusers), small- and medium-sized (≤500 beds) hospitals (68.5% in nonusers, and 74% and 76.7% in short- and long-acting benzodiazepines), and those in the Midwest (24.6%/25.4% short/long-acting versus 16% among nonusers) in TKA; all standardized differences ≥0.1. Similar patterns were observed in THA except for race and comorbidity burden. Notably, among patients with benzodiazepine use, in-hospital postoperative opioid administration (measured in oral morphine equivalents [OMEs]) was substantially higher. This was even more pronounced in patients who received long-acting agents (median OME with no benzodiazepines utilization 192 [IQR, 83-345] vs 256 [IQR, 153-431] with short-acting, and 329 [IQR, 195-540] with long-acting benzodiazepine administration). Benzodiazepine use was also more frequent in patients receiving multimodal analgesia (concurrently 2 or more analgesic modes) and regional anesthesia. Trend analysis showed a persistent high utilization rate of benzodiazepines over the last 14 years.

CONCLUSIONS

Based on a representative sample, 4 of 5 patients undergoing major orthopedic surgery in the United States receive benzodiazepines perioperatively, despite concerns for delirium and delayed postoperative neurocognitive recovery. Notably, benzodiazepine utilization was coupled with substantially increased opioid use, which may project implications for perioperative pain management.

ANTI-INFLAMMATORY EFFECTS OF PROPOXAZEPAM ON DIFFERENT MODELS OF INFLAMMATION

Background. Propoxazepam, 7-bromo-5-(2-chlorophenyl)-3-propoxy-1H-benzo[e][1,4]diazepin-2(3H)-one, is a promising analgesic and anticonvulsant and is on preclinical trial. Objective. The aim of the research was to study the anti-inflammatory and analgesic action of Propoxazepam. Methods. The anti-inflammatory action was evaluated by carrageenan induced rat paw edema, formalin-induced paw licking response in mice and bradykinin-induced pain response in rat models. Results. It was established for the first time that the administration of Propoxazepam caused a significant anti-inflammatory activity when tested in different in vivo chemical experimental models of induced inflammation, i.e. carrageenan-, bradykinin- and formalin-induced inflammation tests. Conclusions. Propoxazepam significantly reduced acute and sub-acute inflammation and proved its efficacy and similar to anti-inflammatory action.

Changes in anxiety levels are followed by changes in behavioral strategy in mice subjected to stress and in the extent of stress-induced analgesia

The experiments reported here demonstrated that corasol increased the extent of analgesia induced by stress and decreased the duration of immobility in mice in a forced swimming test in cold water. Administration of diazepam led to the opposite changes and counteracted the actions of the anxiogen. The effects of the anxiolytic were more apparent in NMRI than mongrel mice, while in mongrel mice the effects of the anxiogen were more marked. Changes in measures following administration of agents were reciprocal in nature. These results lead to the conclusion that that these changes are determined by the level of anxiety, and that the strain differences between mongrel and NMRI mice are also linked with this factor.

Cholecystokinin and endogenous opioid peptides: interactive influence on pain, cognition, and emotion

It is well documented that stressful life experiences contribute to the etiology of human mood disorders. Cholecystokinin (CCK) is a neuropeptide found in high concentrations throughout the central nervous system, where it is involved in numerous physiological functions. A role for CCK in the induction and persistence of anxiety and major depression appears to be conspicuous. While increased CCK has been associated with motivational loss, anxiety and panic attacks, an increase in mesocorticolimbic opioid availability has been associated with coping and mood elevation. The close neuroanatomical distribution of CCK with opioid peptides in the limbic system suggests that there may be an opioid-CCK link in the modulation and expression of anxiety or stressor-related behaviors. In effect, while CCK induces relatively protracted behavioral disturbances in both animal and human subjects following stressor applications, opioid receptor activation may change the course of psychopathology. The antagonistic interaction of CCK and opioid peptides is evident in psychological disturbances as well as stress-induced analgesia. There appears to be an intricate balance between the memory-enhancing and anxiety-provoking effects of CCK on one hand, and the amnesic and anxiolytic effects of opioid peptides on the other hand. Potential anxiogenic and mnemonic influences of site-specific mesocorticolimbic CCK and opioid peptide availability, the relative contributions of specific CCK and opioid receptors, as well as the time course underlying neuronal substrates of long-term behavioral disturbances as a result of stressor manipulations, are discussed.

Effect of pre-operative anxiolysis on postoperative pain response in patients undergoing total abdominal hysterectomy

In a double blind, placebo-controlled trial, we have assessed the effects of pre-operative anxiolysis on postoperative pain scores in 112 ASA I-II women, aged 18-65 years, scheduled to undergo total abdominal hysterectomy. Subjects were randomly allocated to receive either oral diazepam 10 mg (n=56) or placebo (n=56) pre-operatively. Postoperative anxiety, pain scores, analgesic consumption, and sedation were evaluated at several time points during the first 24 h following surgery. Postoperative pain scores were found to be significantly higher in the diazepam group. Trait and state anxiety showed a significant effect on pain scores, independent of the treatment group. No difference was found between the groups in morphine consumption, but there was a significant reduction in morphine consumption with time.

Flumazenil potentiation of postoperative morphine analgesia

OBJECTIVE

The goal of this study was to test the effect of concomitant administration of flumazenil (FL) and morphine (MO) on immediate postoperative analgesia and the MO requirement to control pain in human beings.

DESIGN AND INTERVENTIONS

Thirty-six patients undergoing inguinal hernioplasty under lidocaine epidural anesthesia were enrolled in this double-blind, randomized, controlled study. On the first complaint of pain, either MO (2 mg) only or MO (2 mg) plus FL (0.2 mg) was administered. Additional doses of the same medications administered via a patient-controlled analgesia device with a 10-minute lockout period were available thereafter. The study continued for 2 hours after the loading doses of the medications were administered, with an additional 2-hour period of observation.

RESULTS

Thirty-two patients completed the study. Both groups reached a similar satisfactory equianalgesic state (2 in a 0-10 visual analogue scale). The MO plus FL group consumed 9.5 +/- 1.1 mg of MO versus 14.1 +/- 1.1 mg of MO (p < 0.001) in the MO only group. The MO plus FL patients were subjectively (visual analogue scale) more comfortable and less sedated than the MO patients. "Fine" coordination (using an electronic maze) and "coarse" coordination (measured by transferring a pen from one hand to another as rapidly as possible with both arms placed inside an 80-cm metal frame) in the MO group were worse than in the MO plus FL group. End-tidal CO2 increased and blood pressure decreased in the MO group. There were few and insignificant side effects in the MO group. None of these patients required an MO antagonist, and recovery was prolonged in none.

CONCLUSIONS

Flumazenil afforded lower MO consumption during the immediate postoperative period. Cognitive, hemodynamic, and respiratory functions were better after MO plus FL than after MO alone.

No interactive effects of naltrexone and benzodiazepines on pain during phobic fear

Animal research has shown that anxiety may inhibit pain through the release of endogenous opioids. On the other hand, anxiety is often believed to exacerbate pain in clinical situations, and anxiety reduction has been shown to attenuate the affective component of pain. In the present study phobic anxiety was induced by confronting forty-eight spider phobic subjects with a spider, after which they received two mildly painful electrical stimuli at two different current levels. The benzodiazepine alprazolam (1 mg) was administered to investigate the influence on pain of a reduction in anxiety, while the role of endogenous opioids was studied by administering the opioid antagonist naltrexone (50 mg). Alprazolam resulted in lower anxiety and pain ratings during pain stimulation, supporting the idea that (presumably pain-related) anxiety may increase the experience of pain. Naltrexone did not influence pain and anxiety ratings, nor was there a significant interaction between the two pharmacological manipulations. These findings confirm previous evidence that phobic fear does not necessarily induce an endogenous opioid-mediated analgesia.

On mouse pups and their lactating dams: behavioral consequences of early exposure to oxazepam and interacting factors

Behavioral analysis in animal models appears to be a valuable and sensitive tool for detecting subtle alterations in CNS function, which can be produced by early exposure to small perturbations of sensory experience, hormonal milieu, or exposure to psychotropic agents devoid of major teratogenic potential. Concerning anxiolytics, the more recent work in mice, which is here summarized, was carried out by putting the emphasis on changes in naturally occurring species-typical social responses as a function of early exposure to benzodiazepines. For adult females, on the behavior expressed during the early postpartum period, whereas for infant subjects, on the ontogenetic stage of the establishment of social bonding. Critical issues such as the choice of fostering procedure and rearing conditions are also addressed. Evidences of relationships between changes in social milieu taking place during early rearing-i.e., when dramatic transitions in the neurochemical target system occur- and the adult behavioral response to challenges with BDZ agents are presented. These data strengthen the notion that the modes of reaction of adult animals to the joint influence of physiological and environmental (stimulus) variables are under the influence of events in early ontogenesis. Therefore, a better understanding of the mechanisms-as unveiled by an appropriate use of drug tools-that mediate such a plasticity might have considerable psychobiological and clinical-therapeutical relevance.

Effect of chronic maternal diazepam treatment on the development of stress-induced antinociception in young rats

The use and abuse of benzodiazepines is widespread and we have begun to address whether maternal exposure to these drugs influences the development of opioid systems. We have studied the effect of maternal diazepam treatment on stress-induced antinociception in the neonatal offspring. Diazepam (1 or 10 mg/kg) was administered twice daily to mothers from conception. Pre- and postweanling rat pups were assessed for opioid-mediated stress-induced antinociception by 3-min swimming and measuring nociception using the tail immersion test. In preweanling rats there was stress-induced antinociception in both vehicle- and diazepam-treated animals but in diazepam-treated groups (1 and 10 mg/kg) this was insensitive to reversal by the opioid antagonist naloxone, suggesting that nonopioid systems are operating this response. In postweanling rats a similar insensitivity to naloxone was observed in 1 mg/kg diazepam-treated groups; with 10 mg/kg diazepam there was no significant antinociception. The results suggest that maternal diazepam treatment interferes with the development of stress-mediated responses and that part of this toxicity is due to actions on opioid systems in the CNS.

Pentobarbital, diazepam, and ethanol abolish the interphase diminution of pain in the formalin test: evidence for pain modulation by GABAA receptors

There are two phases to the behavioral response to injection of formalin. After an initial vigorous response, a period of reduced pain occurs 10 to 15 min after formalin, followed by reemergence of pain-related behaviors. These phases are believed to represent acute chemical stimulation of afferent neurons followed by injury-related inflammatory pain. Pentobarbital (10, 15, or 25 mg/kg), diazepam (0.5, 1.5, or 5.0 mg/kg), or ethanol (0.5, 1.0, or 1.5 g/kg) attenuated the diminution of pain between the two phases, so that pain was continuous throughout 60 min of testing, but had no effect on pain scores during the peaks of either phase. The effects of pentobarbital and diazepam were blocked by picrotoxin (2.5 mg/kg), which itself had no effect. Ro 15-1788 also blocked the effect of diazepam. Picrotoxin did not effectively antagonize the effect of ethanol. A high dose of picrotoxin (5.0 mg/kg) caused seizures in some rats and also eliminated the interphase depression of pain. The results suggest that the biphasic time course of formalin pain is produced by a central antinociceptive mechanism that is inhibited by GABAA receptors.

Naloxone-induced hypoalgesia: lack of involvement of the GABA-benzodiazepine receptor complex

Previous evidence has demonstrated that repeated daily administration of the opiate receptor antagonist naloxone prior to assessment of pain sensitivity provokes the development of a nonopioid form of hypoalgesia. The present experiments assessed whether the GABA-benzodiazepine receptor complex may be involved in the mediation of this effect. Male Wistar rats were administered 10 mg/kg naloxone prior to hot-plate tests (48.5 degrees C) for pain sensitivity for 8 consecutive days. Control animals were administered saline prior to, and naloxone 2-4 h after, assessment of pain reactivity. Beginning on the fourth or fifth day of this regimen, animals tested under the influence of naloxone displayed longer paw-lick latencies than controls. Preadministration of the GABAA agonist muscimol (1.0-5.0 mg/kg) and GABAA antagonist bicuculline (0.25-1.0 mg/kg) failed to affect paw-lick latencies in naloxone-tested and control rats. The GABAB receptor agonist baclofen (1.0-5.0 mg/kg) and the benzodiazepine receptor agonist diazepam (1.0-5.0 mg/kg) both elevated paw-lick latencies to the same degree in both groups of animals. These results suggest that the GABA-benzodiazepine receptor complex is not involved in the mediation of naloxone-induced hypoalgesia.

Sexual segregation in infancy and bi-directional benzodiazepine effects on hot-plate response and neophobia in adult mice

In the present experiment, the hypothesis that rearing animals in conditions of sexual segregation in infancy (ISS) would affect their adult behavioral reactivity to drug or environmental challenges was tested. Outbred Swiss CD-1 mouse litters were reduced at birth to six pups according to three conditions: MM (all males), MF (sex-balanced composition), and FF (all females). At weaning (day 21), all mice were rehoused in unisexual groups. At adulthood (day 70), animals were challenged either with BDZ agonist chlordiazepoxide (CDP at 2.5- or 5.0-mg/kg dose) or BDZ receptor partial inverse agonist Ro 15-3505 (RO at 3-, 10-, or 30-mg/kg dose) and assessed in sequence for pain reactivity in a hot-plate apparatus (set at 55 +/- 1 degrees C), for locomotor activity in a Varimex apparatus, and finally for neophobia level by measuring the latency to first approach a novel object. As concerns the hot-plate test, lick latency was significantly shortened in MF females receiving CDP (5.0 mg/kg), while RO was either ineffective in MF females or induced a prominent dose-dependent analgesia in FF females. Activity was decreased by CDP (2.5 mg/kg) and enhanced by RO (3.0 mg/kg). For latency to approach a novel object, males as a whole exhibited shorter times than females. Mixed-sex animals of both sexes were less fearful, being also more explorative than their corresponding unisexually reared groups. In particular, MF males receiving either a 5.0-mg/kg CDP dose or a 3.0-mg/kg RO dose explored the object more often than MM males.(ABSTRACT TRUNCATED AT 250 WORDS)

Corticotropin releasing hormone, interleukin-1 alpha, and tumor necrosis factor-alpha share characteristics of stress mediators

Interleukin-1 alpha and tumor necrosis factor-alpha induce an increase in pain thresholds in the rat. We now show that also the corticotropin releasing hormone induces an analgesic effect that, similarly to what is observed with the two cytokines, is not reversible by naloxone. Moreover, we also show that after the administration of interleukin-1 alpha, tumor necrosis factor-alpha, and corticotropin releasing hormone, naloxone becomes analgesic itself. A similar observation was also made in the human and the experimental animal after exposure to stressful conditions. The results obtained suggest that the two cytokines share with corticotropin releasing hormone some characteristics of stress mediators.