Gabapentin toxicity in renal failure: the importance of dose adjustment

Gabapentin and pregabalin exposures reported to United States poison centers, 2012-2022

BACKGROUND

Gabapentin and pregabalin were originally introduced as anticonvulsant medications but are now also prescribed on- and off-label for multiple medical disorders, especially for pain management. The national opioid crisis has led to increased use of non-opioid pain medications, including gabapentinoids, which has been associated with changing patterns of adverse events associated with these medications. This study investigated the characteristics and trends of gabapentin and pregabalin exposures reported to US poison centers from 2012 to 2022.

METHODS

National Poison Data System data involving gabapentin and pregabalin exposures for 2012 to 2022 were analyzed.

RESULTS

There were 124,161 exposures involving gabapentin and pregabalin as the primary substance reported to US poison centers during the study period. Most exposures involved gabapentin (85.9%), females (59.4%), single-substance exposures (62.9%), or occurred at a residence (97.2%). Suspected suicides accounted for 45.2% of exposures. Most exposures were associated with a minor effect (27.4%) or no effect (34.0%), while 22.1% experienced a serious medical outcome, including 96 fatalities. The rate of gabapentin and pregabalin exposures per one million US population increased by 236.1% from 22.7 in 2012 to 76.5 in 2019 (P < 0.001), followed by a non-significant decrease to 68.5 in 2022 (P = 0.068).

CONCLUSIONS

The rate of gabapentin and pregabalin exposures reported to US poison centers increased by more than 230% from 2012 to 2019 before plateauing from 2019 to 2022. The observed rate trend was driven primarily by gabapentin exposures and by cases associated with suspected suicide. Although most exposures were associated with a minor or no effect, 22% of individuals experienced a serious medical outcome, including 96 fatalities. These findings contribute to the discussion of rescheduling gabapentin as a federally controlled substance, which is the current status of pregabalin. Prevention of suicide associated with gabapentin and pregabalin merits special attention.

Best Practices in Caring for Seriously Ill Patients

Palliative care (PC) is the art and science of providing goal-concordant care, skillfully managing complex and refractory pain and nonpain symptoms, mitigating suffering, and augmenting quality of life for seriously ill patients throughout the course of the illness trajectory. The primary team should provide generalist PC for all seriously ill patients and know when to refer patients to specialist PC. Specialty-level PC services should be reserved for complex problems beyond the scope of primary PC. This article reviews principles and best practices to support patient-centered PC.

Effects of Gabapentin on the Treatment of Behavioral Disorders in Dogs: A Retrospective Evaluation

The use of gabapentin in treating dogs with behavioral disorders is not well described. To characterize behavioral effects of gabapentin, this study surveyed 50 owners whose dogs were prescribed gabapentin at a veterinary behavior-focused practice over a five-year period. Most owners (72%) reported that gabapentin was moderately or very effective at improving their dog's behavior. The majority of owners reported at least one side effect (70%), with sedation being the most common. Sedation was more likely to be seen at doses higher than 30 mg/kg. Specific dose ranges (mg/kg) did not correlate with any other reports of side effects nor effectiveness. Dogs with a diagnosis of conflict-related aggression were more likely to have owners report that gabapentin was effective at improving behavior compared to dogs with other behavioral diagnoses (p = 0.04), while dogs diagnosed with aggression secondary to high arousal were less likely to have owners report that gabapentin was effective (p = 0.01). Overall, reports of effect varied widely and, with the exception of sedation, did not correlate with specific mg/kg dose ranges. Results suggest that some dogs may be more sensitive or resistant to adverse and/or therapeutic effects than others and multiple dosage trials may be needed before finding the best fit.

Gabapentin-Induced Myoclonus in a Patient With Chronic Kidney Disease

Gabapentin contains a cyclohexyl group and is a form of gamma-aminobutyric acid (GABA). Despite its name, gabapentin does not affect the inhibitory neurotransmitter GABA or its receptors. Instead, it acts as a ligand, binding strongly to the α2δ (Ca) channel subunit and interfering with its regulatory function and the release of excitatory neurotransmitters. Gabapentin is approved by the FDA for treating seizure disorders and neuropathic pain, except for trigeminal neuralgia. However, it is frequently used off-label to treat other pain conditions and psychological disorders, such as anxiety. Unlike other drugs, gabapentin is not metabolized in the liver and is solely excreted by the kidneys. Therefore, it is crucial to adjust the dosage in patients with renal insufficiency to avoid severe adverse effects. In this case report, we present a patient with chronic renal impairment who experienced devastating myoclonic jerky movements shortly after increasing his gabapentin dose.

A novel functional role for the classic CNS neurotransmitters, GABA, glycine, and glutamate, in the kidney: potent and opposing regulators of the renal vasculature

The presence of a renal GABA/glutamate system has previously been described; however, its functional significance in the kidney remains undefined. We hypothesized, given its extensive presence in the kidney, that activation of this GABA/glutamate system would elicit a vasoactive response from the renal microvessels. The functional data here demonstrate, for the first time, that activation of endogenous GABA and glutamate receptors in the kidney significantly alters microvessel diameter with important implications for influencing renal blood flow. Renal blood flow is regulated in both the renal cortical and medullary microcirculatory beds via diverse signaling pathways. GABA- and glutamate-mediated effects on renal capillaries are strikingly similar to those central to the regulation of central nervous system capillaries, that is, exposing renal tissue to physiological concentrations of GABA, glutamate, and glycine led to alterations in the way that contractile cells, pericytes, and smooth muscle cells, regulate microvessel diameter in the kidney. Since dysregulated renal blood flow is linked to chronic renal disease, alterations in the renal GABA/glutamate system, possibly through prescription drugs, could significantly impact long-term kidney function.NEW & NOTEWORTHY Functional data here offer novel insight into the vasoactive activity of the renal GABA/glutamate system. These data show that activation of endogenous GABA and glutamate receptors in the kidney significantly alters microvessel diameter. Furthermore, the results show that these antiepileptic drugs are as potentially challenging to the kidney as nonsteroidal anti-inflammatory drugs.

Acute kidney injury-associated delirium: a review of clinical and pathophysiological mechanisms

Acute kidney injury is a known clinical risk factor for delirium, an acute cognitive dysfunction that is commonly encountered in the critically ill population. In this comprehensive review of clinical and basic research studies, we detail the epidemiology, clinical implications, pathogenesis, and management strategies of patients with acute kidney injury-associated delirium. Specifically addressed are the pathological roles of endogenous toxin or drug accumulation, acute kidney injury-mediated neuroinflammation, and acute kidney injury-associated volume overload as discrete potential biological mechanisms of the condition. The optimization of clinical contributors and normalization of renal function are reviewed as pragmatic management strategies in addition to potential and emerging therapeutic approaches.

Extracorporeal Treatment for Gabapentin and Pregabalin Poisoning: Systematic Review and Recommendations From the EXTRIP Workgroup

Toxicity from gabapentin and pregabalin overdose is commonly encountered. Treatment is supportive, and the use of extracorporeal treatments (ECTRs) is controversial. The EXTRIP workgroup conducted systematic reviews of the literature and summarized findings following published methods. Thirty-three articles (30 patient reports and 3 pharmacokinetic studies) met the inclusion criteria. High gabapentinoid extracorporeal clearance (>150mL/min) and short elimination half-life (<5 hours) were reported with hemodialysis. The workgroup assessed gabapentin and pregabalin as "dialyzable" for patients with decreased kidney function (quality of the evidence grade as A and B, respectively). Limited clinical data were available (24 patients with gabapentin toxicity and 7 with pregabalin toxicity received ECTR). Severe toxicity, mortality, and sequelae were rare in cases receiving ECTR and in historical controls receiving standard care alone. No clear clinical benefit from ECTR could be identified although major knowledge gaps were acknowledged, as well as costs and harms of ECTR. The EXTRIP workgroup suggests against performing ECTR in addition to standard care rather than standard care alone (weak recommendation, very low quality of evidence) for gabapentinoid poisoning in patients with normal kidney function. If decreased kidney function and coma requiring mechanical ventilation are present, the workgroup suggests performing ECTR in addition to standard care (weak recommendation, very low quality of evidence).

Machine Learning for Identifying Medication-Associated Acute Kidney Injury

One of the prominent problems in clinical medicine is medication-induced acute kidney injury (AKI). Avoiding this problem can prevent patient harm and reduce healthcare expenditures. Several researches have been conducted to identify AKI-associated medications using statistical, data mining, and machine learning techniques. However, these studies are limited to assessing the impact of known nephrotoxic medications and do not comprehensively explore the relationship between medication combinations and AKI. In this paper, we present a population-based retrospective cohort study that employs automated data analysis techniques to identify medications and medication combinations that are associated with a higher risk of AKI. By integrating multivariable logistic regression, frequent itemset mining, and stratified analysis, this study is designed to explore the complex relationships between medications and AKI in such a way that has never been attempted before. Through an analysis of prescription records of one million older patients stored in the healthcare administrative dataset at ICES (an independent, non-profit, world-leading research organization that uses population-based health and social data to produce knowledge on a broad range of healthcare issues), we identified 55 AKI-associated medications among 595 distinct medications and 78 AKI-associated medication combinations among 7748 frequent medication combinations. In addition, through a stratified analysis, we identified 37 cases where a particular medication was associated with increasing the risk of AKI when used with another medication. We have shown that our results are consistent with previous studies through consultation with a nephrologist and an electronic literature search. This research demonstrates how automated analysis techniques can be used to accomplish data-driven tasks using massive clinical datasets.

The effectiveness of prescription drug monitoring programs at reducing opioid-related harms and consequences: a systematic review

BACKGROUND

In order to address the opioid crisis in North America, many regions have adopted preventative strategies, such as prescription drug monitoring programs (PDMPs). PDMPs aim to increase patient safety by certifying that opioids are prescribed in appropriate quantities. We aimed to synthesize the literature on changes in opioid-related harms and consequences, an important measure of PDMP effectiveness.

METHODS

We completed a systematic review. We conducted a narrative synthesis of opioid-related harms and consequences from PDMP implementation. Outcomes were grouped into categories by theme: opioid dependence, opioid-related care outcomes, opioid-related adverse events, and opioid-related legal and crime outcomes.

RESULTS

We included a total of 22 studies (49 PDMPs) in our review. Two studies reported on illicit and problematic use but found no significant associations with PDMP status. Eight studies examined the association between PDMP status and opioid-related care outcomes, of which two found that treatment admissions for prescriptions opioids were lower in states with PDMP programs (p < 0.05). Of the thirteen studies that reported on opioid-related adverse events, two found significant (p < 0.001 and p < 0.05) but conflicting results with one finding a decrease in opioid-related overdose deaths after PDMP implementation and the other an increase. Lastly, two studies found no statistically significant association between PDMP status and opioid-related legal and crime outcomes (crime rates, identification of potential dealers, and diversion).

CONCLUSION

Our study found limited evidence to support overall associations between PDMPs and reductions in opioid-related consequences. However, this should not detract from the value of PDMPs' larger role of improving opioid prescribing.

Gabapentin dose and the 30-day risk of altered mental status in older adults: A retrospective population-based study

Gabapentin is an effective treatment for chronic neuropathic pain but may cause dizziness, drowsiness, and confusion in some older adults. The goal of this study was to assess the association between gabapentin dosing and adverse outcomes by obtaining estimates of the 30-day risk of hospitalization with altered mental status and mortality in older adults (mean age 76 years) in Ontario, Canada initiated on high dose (>600 mg/day; n = 34,159) compared to low dose (≤600 mg/day; n = 76,025) oral gabapentin in routine outpatient care. A population-based, retrospective cohort study assessing new gabapentin use between 2002 to 2014 was conducted. The primary outcome was 30-day hospitalization with an urgent head computed tomography (CT) scan in the absence of evidence of stroke (a proxy for altered mental status). The secondary outcome was 30-day all-cause mortality. The baseline characteristics measured in the two dose groups were similar. Initiation of a high versus low dose of gabapentin was associated with a higher risk of hospitalization with head CT scan (1.27% vs. 1.06%, absolute risk difference 0.21%, adjusted relative risk 1.29 [95% CI 1.14 to 1.46], number needed to treat 477) but not a statistically significant higher risk of mortality (1.25% vs. 1.16%, absolute risk difference of 0.09%, adjusted relative risk of 1.01 [95% CI 0.89 to 1.14]). Overall, the risk of being hospitalized with altered mental status after initiating gabapentin remains low, but may be reduced through the judicious use of gabapentin, use of the lowest dose to control pain, and vigilance for early signs of altered mental status.

Pain management in critically ill patients: a review of multimodal treatment options

Pain management for critically ill patients provides physicians with the challenge of maximizing patient comfort while avoiding the risks that arise with oversedation. Preventing oversedation has become increasingly important as we better understand the negative impact it has on patients' experiences and outcomes. Current research suggests that oversedation can result in complications such as thromboembolism, pulmonary compromise, immunosuppression and delirium. Fortunately, the analgesic options available for physicians to limit these complications are growing as more treatment modalities are being researched and implemented in the intensive care unit. Our goal is to outline some of the effective and widely utilized tools available to physicians to appropriately and safely manage pain while avoiding oversedation in the critically ill population.

Postoperative pain management in patients with chronic kidney disease

Chronic kidney disease (CKD) is a health care problem with increasing prevalence worldwide. Pain management represents one of the challenges in providing perioperative care for this group of patients. Physicians from different specialties may be involved in pain management of CKD patients, especially in advanced stages. It is important to understand the clinical staging of kidney function in CKD patients as the pharmacotherapeutic pain management strategies change as kidney function becomes progressively impaired. Special emphasis should be placed on dose adjustment of certain analgesics as well as prevention of further deterioration of renal function that could be induced by certain classes of analgesics. Chronic pain is a common finding in CKD patients which may be caused by the primary disease that led to kidney damage or can be a direct result of CKD and hemodialysis. The presence of chronic pain in some of the CKD patients makes postoperative pain management in these patients more challenging. This review focuses on the plans and challenges of postoperative pain management for patient at different stages of CKD undergoing surgical intervention to provide optimum pain control for this patient population. Further clinical studies are required to address the optimal medication regimen for postoperative pain management in the different stages of CKD.

Myoclonus in renal failure: Two cases of gabapentin toxicity

Gabapentin, an AED approved for the adjunctive treatment of partial seizures with/without secondary generalization and for the treatment of postherpetic neuralgia, is frequently used off-label for the treatment of both psychiatric and pain disorders. Since gabapentin is cleared solely by renal excretion, dosing requires consideration of the patient's renal function. Myoclonic activity may occur as a complication of gabapentin toxicity, especially with acute kidney injury or end-stage renal disease. We report 2 cases of myoclonic activity associated with gabapentin toxicity in the setting of renal disease which resolved with discontinuation of gabapentin and treatment with hemodialysis and peritoneal dialysis. As gabapentin has multiple indications and off-label uses, an understanding of myoclonus, neurotoxicity, and renal dosing is important to clinicians in multiple specialties.

Computerized decision support systems: improving patient safety in nephrology

Incorrect prescription and administration of medications account for a substantial proportion of medical errors in the USA, causing adverse drug events (ADEs) that result in considerable patient morbidity and enormous costs to the health-care system. Patients with chronic kidney disease or acute kidney injury often have impaired drug clearance as well as polypharmacy, and are therefore at increased risk of experiencing ADEs. Studies have demonstrated that recognition of these conditions is not uniform among treating physicians, and prescribed drug doses are often incorrect. Early interventions that ensure appropriate drug dosing in this group of patients have shown encouraging results. Both computerized physician order entry and clinical decision support systems have been shown to reduce the rate of ADEs. Nevertheless, these systems have been implemented at surprisingly few institutions. Economic stimulus and health-care reform legislation present a rare opportunity to refine these systems and understand how they could be implemented more widely. Failure to explore this technology could mean that the opportunity to reduce the morbidity associated with ADEs is missed.

Gabapentin toxicity in patients with chronic kidney disease: a preventable cause of morbidity

BACKGROUND

Gabapentin is frequently used as an analgesic in patients with chronic kidney disease. Although gabapentin is well known for its favorable pharmacokinetics, it is exclusively eliminated renally, and patients with chronic kidney disease are at risk for toxicity. Existing literature on such risk is lacking.

METHODS

We examined the Mayo Clinic Rochester database from 1998 to 2007 in patients with serum gabapentin measurements and known medical outcomes. A total of 729 patients were stratified according to their estimated glomerular filtration rate: group I, 126 individuals with estimated glomerular filtration greater than 90 mL/min/1.72 mm(2) [corrected] ; group II, 594 individuals with estimated glomerular filtration less than 90 mL/min/1.72 mm(2) [corrected] without dialysis; group III, 9 individuals with chronic dialysis.

RESULTS

Patients in groups II and III had higher serum gabapentin levels (8.39+/-0.32 microL/mL and 58.8+/-10.22 microL/mL, respectively) than in group I (5.52+/-0.32 microL/mL, P<.01). Toxicity occurred exclusively in groups II (5.56%) and III (77.8%); toxic manifestations were more severe in group III than in group II. Elderly individuals with multiple comorbidities were overrepresented in those with toxic manifestations. Gabapentin toxicity was suspected initially in only 41.5% of symptomatic cases.

CONCLUSION

Gabapentin toxicity in patients with chronic kidney disease is underrecognized. Patients with chronic kidney disease often receive inappropriately high gabapentin dosage for their kidney function, occasioning overt toxicity; advanced age and comorbidity predispose these patients for toxicity. Heightened awareness of such preventable risk, amid the chronic kidney disease epidemic, would be cost-effective and improve healthcare quality.

Gabapentin-induced rhabdomyolysis in a patient with diabetic neuropathy

Gabapentin (GBP) is a drug which is frequently used in diabetic neuropathy. Common adverse effects of GBP include drowsiness, dizziness, ataxia, somnolence, and fatigue. Rhabdomyolysis is an extremely rare side effect of GBP. In this report we describe a case of GBP-induced rhabdomyolysis in a 63-year-old diabetic woman. She presented with severe muscle pain in her extremities, fatigue, decreased urine output and urine discoloration within 3 weeks after starting treatment with GBP (900 mg/day) for diabetic neuropathy. Laboratory tests revealed extreme elevations of muscle enzymes, increased creatinine and potassium levels. She required hemodialysis as a result of anuria. Investigation confirmed the diagnosis of rhabdomyolysis, and discontinuation of GBP resulted in resolution of clinical and biochemical features of rhabdomyolysis.