Introduction. Gabapentin is an anti-epileptic drug which is also used for the treatment of postoperative pain and a variety of psychiatric diseases including chronic anxiety disorders. We tested the hypothesis that compared with a placebo control, gabapentin would reduce preoperative anxiety in patients undergoing total hip arthroplasty.



Methods.  Following ethics approval, patients participating in a larger double blind, randomized, trial of multimodal analgesia were given either gabapentin 600 mg (N = 22) or placebo (N = 48) 2 hours before spinal anesthesia. Prior to administering the study medication, baseline anxiety levels were measured using a visual analog scale (VAS). Two hours after the ingestion of gabapentin or placebo, and prior to surgery, patients again rated their anxiety using a VAS.



Results.  Anxiety scores did not differ significantly between the groups either before (P = 0.95) or 2 hours after (P = 0.61) ingestion of gabapentin or placebo. Baseline anxiety and postdrug anxiety scores failed to demonstrate a significant association with maximal postoperative pain at rest, maximal postoperative pain with movement, and cumulative morphine consumption 48 hours after surgery.



Conclusions.  Administration of gabapentin 600 mg prior to surgery does not reduce preoperative anxiety.

Gabapentin Does Not Reduce Preoperative Anxiety When Given Prior to Total Hip Arthroplasty

A 3-year-old female patient developed chorea possibly due to an interaction between phenytoin, phenobarbital and clobazam used for generalized tonic clonic seizures. Phenytoin withdrawal resulted in recovery within 24 hours. Post reaction computerized tomography (CT)-scan of brain was normal. Combined use of anti-seizure drugs and interactions between them may be responsible for the reaction. Therapeutic drug monitoring is important while prescribing two or more anti-seizure drugs.

Phenytoin induced chorea in a pediatric patient: An interaction between phenytoin, phenobarbital and clobazam.

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The Effects of Gabapentin on Pre-operative Anxiety, Morphine Consumption and Pain after Surgery.

We describe a case of an 80-year-old woman who developed disabling asterixis after taking gabapentin for post-herpetic neuropathy. She had end-stage renal disease necessitating intermittent hemodialysis for the previous 5 years. She had begun taking gabapentin about 1 week prior to being admitted to the hospital, and a family member observed a new tremor developing about 3 days prior to hospital admission. Neurologic examination revealed diffuse axial and appendicular negative myoclonus. Because of her renal dysfunction, the gabapentin dose was empirically reduced from 300 mg by mouth three times daily to 100 mg three times daily. Gabapentin was discontinued on hospital day 5 because of concerns for drug toxicity causing the abnormal movements. Two days after gabapentin was discontinued, she has complete resolution of her negative myoclonus. J Med Cases. 2015;6(7):285-286 doi: http://dx.doi.org/10.14740/jmc2143w

Disabling Asterixis Induced By Gabapentin

Movement disorders associated with antiseizure medications: A systematic review

Background: Chorea is a hyperkinetic movement disorder characterized by irregular, flowing, nonstereotyped, random, involuntary movements Huntington disease (HD) and drug-induced chorea account for >50% of adult-onset cases Chorea associated with gabapentin, an anticonvulsant, has not been well documented Objective: The purpose of this article was to report a case of chorea that developed in an elderly man being treated with gabapentin for severe anxiety Case summary: A 75-year-old white man (height, 1651 cm; weight, 658 kg; body mass index, 196 kg/m2) with anxiety disorder not otherwise specified was admitted to a geriatric medicine psychiatric unit in Connecticut because of worsening symptoms of anxiety affecting his cognitive ability On evaluation, the patient had choreiform movements involving the neck, trunk, upper and lower extremities, and tongue The patient reported that symptoms began after taking gabapentin 300 mg PO TID (prescribed by his geriatrician) for the treatment of anxiety The patient had been taking gabapentin for >1 month when the symptoms first appeared There was no known family history of HD, and patient workup was unremarkable for other conditions (eg, vascular disease of the brain, progressive dementia, infectious and metabolic disorders) that might present with chorea The chorea lasted for ~4 months and resolved within 2 days after gabapentin discontinuation Conclusion: This article reports a case of chorea in an elderly patient who was receiving gabapentin for the treatment of anxiety After gabapentin discontinuation, the chorea resolved completely, indicating a probable adverse drug reaction

Rehan Aziz

Papers

Chorea associated with gabapentin use in an elderly man.