Gabapentin-Induced Severe Myopathy

A comprehensive review of the typical and atypical side effects of gabapentin

BACKGROUND

Gabapentin, a widely prescribed medication for various neuropathic pain conditions, has demonstrated efficacy in managing diverse neurological disorders. While conventional side effects are well-documented, a growing body of evidence suggests the existence of atypical side effects, necessitating comprehensive exploration. This paper aims to systematically review and summarize the literature on the atypical side effects of gabapentin, shedding light on manifestations beyond the conventional spectrum.

METHODS

A systematic review was conducted, encompassing peer-reviewed articles published up to the knowledge cutoff date in November 2023. Databases, specifically PubMed, were searched for relevant studies, focusing on atypical side effects such as myoclonus, ataxia, pediatric aggression, respiratory depression, pneumonia, pregnancy complications, sleep interference, encephalopathy, peripheral edema, suicidal ideation, dyskinesia, anorgasmia, and myopathy. Inclusion criteria comprised studies with a focus on gabapentin-related atypical side effects, published in recognized journals and involving human subjects.

RESULTS

The review identified a spectrum of atypical side effects associated with gabapentin use, ranging from neurological manifestations like myoclonus and ataxia to behavioral changes such as pediatric aggression and suicidal ideation. Additionally, respiratory complications, pregnancy-related issues, sleep disturbances, and rare complications like encephalopathy and myopathy were observed. Literature synthesis provided insights into the incidence, clinical presentation, and potential mechanisms underlying these atypical side effects.

CONCLUSION

This comprehensive review highlights the diverse range of atypical side effects associated with gabapentin use, expanding beyond conventional knowledge. Healthcare practitioners must be cognizant of these manifestations, recognizing their potential impact on patient well-being. As clinical decision-making relies on a thorough understanding of a medication's side effect profile, this review contributes to enhancing awareness and fostering informed practices in the prescription and management of gabapentin. Further research is warranted to elucidate the mechanisms and risk factors associated with these atypical side effects, refining our understanding of gabapentin's safety profile.

The pharmacology activities of Angelica keiskei Koidzumi and its efficacy and safety in humans

Chronic exposure to elevated levels of pro-oxidant factors may cause structural failings at the mitochondrial DNA level and alteration of antioxidant enzymes (glutathione peroxidase, catalase, and superoxide dismutase). Oxidative stress is an imbalance between the capacity of endogenous non-enzymatic antioxidants (glutathione, alpha-lipoic acid, uric acid, ferritin, metallothionein, melatonin, and bilirubin) and the occurrence of pro-oxidant factors which may lead to the pathogenesis of various diseases that affects the kidneys, pancreas, central nervous system, and cardiovascular system. Therefore, the utilization of medicinal plants with antioxidant activity, e.g., Angelica keiskei Koidzumi which contains chalcones, is interesting to be explored. Chalcones exhibit direct and indirect antioxidant activity and prevent oxidative stress by decreasing ROS, RNS, and superoxide production. In this review, we discuss the pharmacology activities of A. keiskei Koidzumi and its efficacy in humans. The articles were explored on PubMed and Google Scholar databases and based on the titles and abstracts related to the topic of interest, and 55 articles were selected. Two main chalcones of this plant, 4-hydroxyderricin and xanthoangelol, have been reported for their various pharmacology activities. The efficacy of A. keiskei was confirmed in anti-obesity, hepatoprotective, anti-diabetes mellitus, and increasing plasma antioxidants in patients with metabolic syndrome. A keiskei is safe as proven by only mild or no adverse events reported, thus it is prospective to be further developed as an antioxidant nutraceutical.

Gabapentin for chronic refractory cough: A system review and meta-analysis

Objective

To evaluate the efficacy and safety of gabapentin in the treatment of chronic refractory cough by Meta-Analysis.

Methods

Literatures were retrieved from PubMed, Embase (OvidIP), Cochrane Library, CNKI, VIP, Wanfang Database and China Biomedical Management System and eligible prospective studies were screened. Data were extracted and analyzed by using RevMan 5.4.1 software.

Results

Six articles (2 RCTs and 4 prospective studies) with 536 participants were finally included. Meta-analysis showed that gabapentin was better than placebo in cough-specific quality of life (LCQ score, MD = 4.02, 95%CI [3.26,4,78], Z = 10.34, P < 0.00001), cough severity (VAS score, MD = -29.36, 95% CI (-39.46, -19.26), Z = 5.7, P < 0.00001), cough frequency (MD = -29.87, 95% CI [- 43.84, -15.91], Z = 4.19, P < 0.0001) and therapeutic efficacy (RR = 1.37,95%CI [1.13,1.65], Z = 3.27, P = 0.001), and equal in safety (RR = 1.32,95%CI [0.47,3.7], Z = 0.53, P = 0.59). Gabapentin was similar to other neuromodulators in therapeutic efficacy (RR = 1.07,95%CI [0.87,1.32], Z = 0.64, P = 0.52), but its safety was better.

Conclusion

Gabapentin is effective in the treatment of chronic refractory cough in both subjective and objective evaluations, and its safety is better than other neuromodulators.

Effects of Gabapentin and Pregabalin on Calcium Homeostasis: Implications for Physical Rehabilitation of Musculoskeletal Tissues

PURPOSE OF REVIEW

In this review, we discuss the mechanism of action of gabapentinoids and the potential consequences of long-term treatment with these drugs on the musculoskeletal system.

RECENT FINDINGS

Gabapentinoids, such as gabapentin (GBP) and pregabalin (PGB) were designed as antiepileptic reagents and are now commonly used as first-line treatment for neuropathic pain and increasingly prescribed off-label for other pain disorders such as migraines and back pain. GBP and PGB exert their analgesic actions by selectively binding the α₂δ₁ auxiliary subunit of voltage-sensitive calcium channels, thereby inhibiting channel function. Numerous tissues express the α₂δ₁ subunit where GBP and PGB can alter calcium-mediated signaling events. In tissues such as bone, muscle, and cartilage, α₂δ₁ has important roles in skeletal formation, mechanosensation, and normal tissue function/repair that may be affected by chronic use of gabapentinoids. Long-term use of gabapentinoids is associated with detrimental musculoskeletal outcomes, including increased fracture risk. Therefore, understanding potential complications is essential for clinicians to guide appropriate treatments.

Gabapentin-induced myositis in a patient with spinal cord injury - a case report

Myositis and rhabdomyolysis are the same forms of myopathy, with rhabdomyolysis being a more severe form of myopathy. Gabapentin is frequently used in patients with spinal cord injury for neuropathic pain. We report a case of probable gabapentin-induced myositis in a patient with spinal cord injury who was on an increasing dose of gabapentin.

This paraplegic patient was receiving an increasing dose of gabapentin for neuropathic pain in the lower limbs. Gabapentin-induced myositis was diagnosed by a combination of new-onset generalized body pain with tenderness, an increase in creatine kinase, elevated myoglobin levels, and a score of 6 on the Naranjo adverse drug reaction probability scale. Withdrawal of the gabapentin resolved the symptoms completely. Blood parameters became normal within two weeks.

We suggest that myopathy, in the form of myositis, should be recognized as a potential side effect of gabapentin in the literature.

Mining and visualizing high-order directional drug interaction effects using the FAERS database

Background

Adverse drug events (ADEs) often occur as a result of drug-drug interactions (DDIs). The use of data mining for detecting effects of drug combinations on ADE has attracted growing attention and interest, however, most studies focused on analyzing pairwise DDIs. Recent efforts have been made to explore the directional relationships among high-dimensional drug combinations and have shown effectiveness on prediction of ADE risk. However, the existing approaches become inefficient from both computational and illustrative perspectives when considering more than three drugs.

Methods

We proposed an efficient approach to estimate the directional effects of high-order DDIs through frequent itemset mining, and further developed a novel visualization method to organize and present the high-order directional DDI effects involving more than three drugs in an interactive, concise and comprehensive manner. We demonstrated its performance by mining the directional DDIs associated with myopathy using a publicly available FAERS dataset.

Results

Directional effects of DDIs involving up to seven drugs were reported. Our analysis confirmed previously reported myopathy associated DDIs including interactions between fusidic acid with simvastatin and atorvastatin. Furthermore, we uncovered a number of novel DDIs leading to increased risk for myopathy, such as the co-administration of zoledronate with different types of drugs including antibiotics (ciprofloxacin, levofloxacin) and analgesics (acetaminophen, fentanyl, gabapentin, oxycodone). Finally, we visualized directional DDI findings via the proposed tool, which allows one to interactively select any drug combination as the baseline and zoom in/out to obtain both detailed and overall picture of interested drugs.

Conclusions

We developed a more efficient data mining strategy to identify high-order directional DDIs, and designed a scalable tool to visualize high-order DDI findings. The proposed method and tool have the potential to contribute to the drug interaction research and ultimately impact patient health care.

Availability and implementation

http://lishenlab.com/d3i/explorer.html

A case of gabapentin overdose induced rhabdomyolysis requiring renal replacement therapy

We report a rare case with gabapentin overdose that caused severe rhabdomyolysis and acute tubular necrosis which required renal replacement therapy. A better awareness of its adverse effect and a close follow-up of laboratory tests are recommended. Prescribers should also be aware of high-risk population and monitor for signs of abuse.

Radiologic Findings in Gabapentin-Induced Myositis

Throughout recent years, Gabapentin has become increasingly used for the treatment of neuropathic pain. We report on a case of a 31 year old female who presented to the emergency department with unilateral leg pain, weakness, and swelling after increasingly titrating her Gabapentin dosage over three weeks. Magnetic resonance imaging confirmed the presence of myositis confined to the left thigh and the patient's symptoms and laboratory abnormalities resolved following Gabapentin cessation. While Gabapentin-induced myositis and rhabdomyolysis is a rare entity, it should be a diagnostic consideration for radiologists, particularly in the absence of infection or trauma.

Review about gabapentin misuse, interactions, contraindications and side effects

The current work is targeted to review the risks of gabapentin misuse, its potential interactions with other drugs, side effects and use contraindications. This review consists of a total of 99 biographical references (from the year 1983 to 2016). A publication search of PubMed was performed from January 1983 to December 2016. It included animal studies, clinical studies, case studies and reviews related to gabapentin misuse, potential interactions, side effects and use contraindications. The search terms were gabapentin, anticonvulsant and antiepileptic. In general, it seems that gabapentin has risks of being misused based on the increased level of prescriptions, related fatalities, recreational misuse and higher doses of self-administration. The main reasons for gabapentin misuse are as follows: getting high, alleviating opioid withdrawal symptoms and potentiating methadone effects. Some of the main substances that interact with gabapentin are morphine, caffeine, losartan, ethacrynic acid, phenytoin, mefloquine and magnesium oxide. Some of the side effects caused by gabapentin are teratogenicity, hypoventilation, respiratory failure and myopathy. Finally, reports in general contraindicate the use of gabapentin in conditions such as myasthenia gravis and myoclonus.

A case of gabapentin-induced rhabdomyolysis requiring renal replacement therapy

Gabapentin is commonly used for controlling convulsions, restless pain syndrome, and pain in diabetic neuropathy. Common side effects include dizziness, somnolence, ataxia, peripheral edema, and confusion; gabapentin-induced rhabdomyolysis is rarely reported. To date, the reported cases of gabapentin-induced rhabdomyolysis have been associated with patients with multiple underlying diseases and assuming multiple medicines for various reasons. In this report, we describe a case of gabapentin-induced rhabdomyolysis in a 32-year-old woman with no medical history. We also review related literature and discuss the possible mechanism and the association with other factors. This case shows that gabapentin can induce rhabdomyolysis in healthy patients and that clinicians must consider the possible association between gabapentin and rhabdomyolysis.

Surgical treatment for muscle injuries

Muscle injury causes functional impairment. The healing process takes time and fibrotic tissue can result. Recurrence and delayed recovery remain as unsolved problems. Surgical intervention can be a feasible alternative to avoid early and late complications associated with complete muscle tear in attempt to improve functional results. This article hopes to provide an update about surgical treatments for muscle tears in different scenarios.

Implications and mechanism of action of gabapentin in neuropathic pain

Gabapentin is an anti-epileptic agent but now it is also recommended as first line agent in neuropathic pain, particularly in diabetic neuropathy and post herpetic neuralgia. α2δ-1, an auxillary subunit of voltage gated calcium channels, has been documented as its main target and its specific binding to this subunit is described to produce different actions responsible for pain attenuation. The binding to α2δ-1 subunits inhibits nerve injury-induced trafficking of α1 pore forming units of calcium channels (particularly N-type) from cytoplasm to plasma membrane (membrane trafficking) of pre-synaptic terminals of dorsal root ganglion (DRG) neurons and dorsal horn neurons. Furthermore, the axoplasmic transport of α2δ-1 subunits from DRG to dorsal horns neurons in the form of anterograde trafficking is also inhibited in response to gabapentin administration. Gabapentin has also been shown to induce modulate other targets including transient receptor potential channels, NMDA receptors, protein kinase C and inflammatory cytokines. It may also act on supra-spinal region to stimulate noradrenaline mediated descending inhibition, which contributes to its anti-hypersensitivity action in neuropathic pain.

Facilitating adverse drug event detection in pharmacovigilance databases using molecular structure similarity: application to rhabdomyolysis

BACKGROUND

Adverse drug events (ADE) cause considerable harm to patients, and consequently their detection is critical for patient safety. The US Food and Drug Administration maintains an adverse event reporting system (AERS) to facilitate the detection of ADE in drugs. Various data mining approaches have been developed that use AERS to detect signals identifying associations between drugs and ADE. The signals must then be monitored further by domain experts, which is a time-consuming task.

OBJECTIVE

To develop a new methodology that combines existing data mining algorithms with chemical information by analysis of molecular fingerprints to enhance initial ADE signals generated from AERS, and to provide a decision support mechanism to facilitate the identification of novel adverse events.

RESULTS

The method achieved a significant improvement in precision in identifying known ADE, and a more than twofold signal enhancement when applied to the ADE rhabdomyolysis. The simplicity of the method assists in highlighting the etiology of the ADE by identifying structurally similar drugs. A set of drugs with strong evidence from both AERS and molecular fingerprint-based modeling is constructed for further analysis.

CONCLUSION

The results demonstrate that the proposed methodology could be used as a pharmacovigilance decision support tool to facilitate ADE detection.

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.