Gabapentin modifies extracellular opioid peptide content in amygdala: a microdialysis study

Gabapentin is Associated With Decreased Postoperative Opioid Use and Length of Stay After Appendectomy in Children With Perforated Appendicitis: A Propensity Score-Matched Analysis

BACKGROUND

Gabapentin is increasingly used as an off-label, opioid-sparing pain medication in children. We investigated perioperative gabapentin administration and postoperative opioid use in children who underwent appendectomy for perforated appendicitis.

METHODS

A retrospective cohort study of healthy children ages 2-18 years undergoing appendectomy for perforated appendicitis from 2014 to 2019 was performed using the Pediatric Health Information System®. Propensity score matched (PSM) analysis was conducted with 1:1 matching based on patient and hospital characteristics. Multivariable linear regression analysis was used to evaluate an association between gabapentin, postoperative opioid use, and postoperative length of stay.

RESULTS

Of 29,467 children with perforated appendicitis who underwent appendectomy, 236 (0.8%) received gabapentin. In 2014, <10 children received gabapentin, but by 2019, 110 children received gabapentin. On univariate analysis of the PSM cohort, children receiving gabapentin had decreased total postoperative opiate use (2.3 SD ± 2.3 versus 3.0 SD ± 2.5 days, p < 0.001). On adjusted analysis, children receiving gabapentin had 0.65 fewer days of postoperative total opioid use (95% CI: -1.09, -0.21) and spent 0.69 fewer days in the hospital after surgery (95% CI: -1.30, -0.08).

CONCLUSION

While overall use is infrequent, gabapentin is increasingly administered to children with perforated appendicitis who undergo an appendectomy and is associated with decreased postoperative opioid use and reduced postoperative length of stay. Multimodal pain management strategies incorporating gabapentin may reduce postoperative opioid consumption, but further studies of drug safety are needed for this off-label use in children undergoing surgery.

LEVEL OF EVIDENCE

III.

An Atypical Withdrawal Syndrome in Neonates Prenatally Exposed to Gabapentin and Opioids

We report a retrospective case series of 19 infants exposed to both opioids and gabapentin prenatally. We describe a unique behavioral phenotype in 15 of these infants and report a treatment strategy.

Abuse of Gabapentin is Associated with Opioid Addiction

The objective of this study was to evaluate the extent of gabapentin misuse in a dually diagnosed correctional population, and to evaluate if this abuse is specific to the presence of an opioid use disorder (OUD). Two-hundred and fifty former inmates, living in a correctional community center, who were referred for a psychiatric evaluation, were asked, through a brief written questionnaire, whether or not they used the following drugs for non-medical use in the past: opiates, gabapentin, buproprion, quetiapine, and fluoxetine. The average age of this population was 37.2 ± 12.1 years (n = 250). Sixty-four percent were male, 72 % were white, 27 % were black, and 1 % was Hispanic. All patients had substance use disorders, the large majority (72 %) to more than one substance. Fifty-eight percent had an opioid use disorder, again mostly in combination with other drugs and/or alcohol. Depressive disorders and attention deficit hyperactivity disorder were the most common psychiatric conditions. Sixty-two percent of patients reported prescription drug misuse of any kind. As expected, a high percent (55 %) reported opiate misuse. No patient reported fluoxetine misuse. Sixteen percent reported having misused gabapentin in the past. Of patients with an opioid use disorder (OUD: n = 145), 26 % endorsed gabapentin abuse while only 4 % of patients without an OUD (n = 105) endorsed the non-medical use of gabapentin. This difference was highly statistically significant (Chi square χ² = 21.6, p < 0.0001). A growing concern about gabapentin misuse was supported in this study: 26 percent of opiate addicted patients reported illegally obtaining, overusing, or malingering problems to obtain gabapentin. This study highlights the fact that gabapentin abuse appears specific to an opioid addicted population.

Gabapentin for Perioperative Analgesia in Otorhinolaryngology-Head and Neck Surgery: Systematic Review

OBJECTIVE

Recent research has investigated the role of gabapentin in perioperative pain relief in otorhinolaryngology-head and neck surgery. This review aims to identify whether sufficient evidence exists for the routine use of gabapentin in the perioperative setting.

DATA SOURCES

MEDLINE, Cochrane CENTRAL, EMBASE, and Google Scholar.

REVIEW METHODS

A comprehensive systematic search was performed with keywords for articles up to November 2015. The systematic review included all randomized, placebo-, and active-controlled trials investigating the role of perioperative gabapentin for pain in otorhinolaryngology-head and neck surgery. The studies were assessed for risk of bias and selected and reviewed by the main author. Selected trials were required to have data in the form of pain intensity scores, analgesic consumption, adverse effects, or return to normal function.

RESULTS

A total of 14 randomized controlled trials were included, of which 4 had an active control. The placebo-controlled trials included 4 for tonsillectomy, 3 for rhinology, and 3 for thyroidectomy. These studies were not suitable for meta-analysis. Trial quality involving gabapentin in tonsillectomy surgery is variable. The higher-quality studies reported significantly reduced analgesic consumption in the gabapentin groups, with the effect on pain scores less clear. There was a significant benefit, within the first 24 hours, in pain and analgesic consumption as compared with placebo favoring the gabapentin groups following rhinologic and thyroid surgery.

CONCLUSION

Overall, gabapentin appears to have a significant beneficial effect on perioperative pain relief and analgesic consumption in otorhinolaryngology-head and neck surgery procedures within the first 24 hours.

Gabapentin in the treatment of neuropathic pain

This paper reviews the pharmacology and clinical effectiveness of gabapentin in the treatment of neuropathic pain. Gabapentin has antihyperalgesic and antiallodynic properties but does not have significant actions as an anti-nociceptive agent. Its mechanisms of action appear to be a complex synergy between increased GABA synthesis, non-NMDA receptor antagonism and binding to the alpha2delta subunit of voltage dependent calcium channels. The latter action inhibits the release of excitatory neurotransmitters. Clinically, several large randomized controlled trials have demonstrated its effectiveness in the treatment of a variety of neuropathic pain syndromes. Patients with neuropathic pain can expect a mean reduction in pain score of 2.05 points on an 11 point numerical rating scale compared with a reduction of 0.94 points if they had taken the placebo. Around 30% of patients can expect to achieve more than 50% pain relief and a similar number will also experience minor adverse events; the most common of which are somnolence and dizziness. In patients with neuropathic pain due to cancer, higher response rates might be observed with gabapentin when administered with opioids because of a synergistic interaction.

A microdialysis study of the novel antiepileptic drug levetiracetam: extracellular pharmacokinetics and effect on taurine in rat brain

Using a rat model which allows serial blood sampling and concurrent brain microdialysis sampling, we have investigated the temporal kinetic inter-relationship of levetiracetam in serum and brain extracellular fluid (frontal cortex and hippocampus) following systemic administration of levetiracetam, a new antiepileptic drug. Concurrent extracellular amino acid concentrations were also determined. After administration (40 or 80 mg kg(-1)), levetiracetam rapidly appeared in both serum (T(max), 0.4 - 0.7 h) and extracellular fluid (T(max), 2.0 - 2.5 h) and concentrations rose linearly and dose-dependently, suggesting that transport across the blood-brain barrier is rapid and not rate-limiting. The serum free fraction (free/total serum concentration ratio; mean+/-s.e.mean range 0.93 - 1.05) was independent of concentration and confirms that levetiracetam is not bound to blood proteins. The kinetic profiles for the hippocampus and frontal cortex were indistinguishable suggesting that levetiracetam distribution in the brain is not brain region specific. However, t(1/2) values were significantly larger than those for serum (mean range, 3.0 - 3.3 h vs 2.1 - 2.3 h) and concentrations did not attain equilibrium with respect to serum. Levetiracetam (80 mg kg(-1)) was associated with a significant reduction in taurine in the hippocampus and frontal cortex. Other amino acids were unaffected by levetiracetam. Levetiracetam readily and rapidly enters the brain without regional specificity. Its prolonged efflux from and slow equilibration within the brain may explain, in part, its long duration of action. The concurrent changes in taurine may contribute to its mechanism of action.

Endogenous opiates: 1999

This paper is the twenty-second installment of the annual review of research concerning the opiate system. It summarizes papers published during 1999 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; learning, memory, and reward; eating and drinking; alcohol and other drugs of abuse; sexual activity, pregnancy, and development; mental illness and mood; seizures and other neurologic disorders; electrical-related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregulation; and immunologic responses.