Non-convulsive status epilepticus in two patients receiving tiagabine add-on treatment

Tiagabine-related status epilepticus: a case report and systematic literature review

Tiagabine-related status epilepticus (SE) is an uncommon complication of tiagabine use. We aimed to detail the features and outcomes in a patient with tiagabine poisoning and review the relevant literature. We describe a case of tiagabine-related SE and literature review based on a 1995-2019 PubMed search. We report the case of a 30-year-old man with super-refractory SE after tiagabine poisoning. He fully recovered after 72 h of general anesthesia and was discharged from the ICU on day 16. A literature review showed distinct features among patients with tiagabine-related SE. Tiagabine side effects were characterized by non-convulsive SE after a slight increase in tiagabine dose and a rapid favorable evolution after benzodiazepine and early tiagabine withdrawal. Generalized convulsive SE was a complication of voluntary or involuntary tiagabine poisoning and was particularly refractory. Both presentations are characterized by a return to baseline after prompt and adequate management. Tiagabine-related SE electroclinical features vary according to the underlying pathophysiological mechanism and can be life threatening. Recovery is the rule after tiagabine withdrawal and SE management with progressive therapeutic escalation guided by response to prior anticonvulsant treatments.

Tiagabine in clinical practice: effects on seizure control and behavior

OBJECTIVE

Preapproval randomized controlled trials of antiepileptic drugs provide data in limited patient groups. We assessed the side effect and seizure reduction profile of tiagabine (TGB) in typical clinical practice.

METHODS

Investigators recorded adverse effect (AE), seizure, and assessment-of-benefit data prospectively in sequential patients treated open label with TGB.

RESULTS

Two hundred ninety-two patients (39 children) were enrolled to be treated long term with TGB. Seizure types were focal-onset (86%), generalized-onset (12%), both focal- and generalized-onset (0.3%), and multiple associated with Lennox-Gastaut Syndrome (2%). Two hundred thirty-one received at least one dose of TGB (median = 28 mg/day) and had follow-up seizure or AE data reported. Common AEs were fatigue, dizziness, psychomotor slowing, ataxia, gastrointestinal upset, weight change, insomnia, and "others" (mostly behavioral). Serious AEs occurred in 19 patients: behavioral effects (n = 12), status epilepticus (n = 3), others (n = 3), and sudden unexplained death (n = 1). No patients experienced suicidal ideation/behavior, rash, nephrolithiasis, or organ failure. Seizure outcomes were seizure freedom (5%), ≥75% reduction (12%), ≥50% reduction (23%), and increased number of seizures (17%), or new seizure type (1%).

CONCLUSIONS

Behavioral AEs occurred in a larger proportion of patients compared to those reported in TGB preapproval randomized controlled trials. A moderate percentage of patients had a meaningful reduction in seizure frequency. In clinical practice, TGB remains a useful antiepileptic drug.

Tiagabine for acute affective episodes in bipolar disorder

BACKGROUND

Bipolar disorder is a common recurrent illness with high levels of chronicity. Treatment resistance persists despite the use of established medications, such as lithium and valproate. New medications are required for the treatment of refractory cases. Some open-label reports have suggested that the anticonvulsant tiagabine may be efficacious in bipolar disorder. There is a need to clarify the evidence available, in the form of randomised controlled trials, for its use in the treatment of acute affective episodes in bipolar disorder.

OBJECTIVES

To review the evidence for the efficacy and acceptability of tiagabine in the treatment of acute mood episodes in bipolar disorder.

SEARCH METHODS

In this update, we searched the Cochrane Depression, Anxiety and Neurosis Group's Specialised Register (CCDANCTR-Studies and CCDANCTR-References) to October 2012. This register contains relevant randomised controlled trials from: The Cochrane Library (all years), EMBASE (1974 to date), MEDLINE (1950 to date) and PsycINFO (1967 to date). We examined reference lists of relevant papers and major textbooks of affective disorder. We contacted authors, other experts in the field and pharmaceutical companies for knowledge of suitable published or unpublished trials. We handsearched specialist journals and conference proceedings.

SELECTION CRITERIA

Randomised controlled trials, which compared tiagabine with placebo or with active agents in the treatment of any acute mood episodes in bipolar disorder in adults, male and female, aged 18 to 74 years.

DATA COLLECTION AND ANALYSIS

Two review authors performed data extraction and methodological quality assessment independently. For analysis, we planned to use risk ratio for binary efficacy outcomes and mean difference or standardised mean difference for continuously distributed outcomes.

MAIN RESULTS

In this updated review we found no studies which fulfilled the Cochrane criteria for randomised controlled trials.

AUTHORS' CONCLUSIONS

We found no randomised controlled trials of tiagabine in the treatment of acute episodes of bipolar disorder. However, there are reports that a number of patients suffered episodes of syncope or seizure. Further investigation of the efficacy and acceptability of tiagabine in the treatment of acute affective episodes of bipolar disorder should await the clarification of the nature of the reported episodes of syncope and seizure-like activity and an examination of the level of risk involved.

Tiagabine in the treatment of acute affective episodes in bipolar disorder: efficacy and acceptability

BACKGROUND

Bipolar disorder is a common recurrent illness with high levels of chronicity. Treatment resistance persists despite the use of established medications, such as lithium and valproate. New medications are required for the treatment of refractory cases. Some open-label reports have suggested that the anticonvulsant tiagabine may be efficacious in bipolar disorder. There is a need to clarify the evidence available, in the form of randomised controlled trials, for its use in the treatment of acute affective episodes in bipolar disorder

OBJECTIVES

To review the evidence for the efficacy and acceptability of tiagabine in the treatment of acute mood episodes in bipolar disorder.

SEARCH STRATEGY

The following databases were searched on 13-10-2005. The Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Registers (CCDANCTR-Studies and CCDANCTR-References),The Cochrane Controlled Clinical Trials Register (CCCTR),EMBASE,MEDLINE,LILACS,PsycLIT andPsyndex. Reference lists of relevant papers and major textbooks of mood disorder were searched. Handsearches were done (specialist journals and conference proceedings). Authors, other experts in the field and pharmaceutical companies were contacted for knowledge of suitable published or unpublished trials.

SELECTION CRITERIA

Randomised controlled trials, which compared tiagabine with placebo or with active agents in the treatment of any acute mood episodes in bipolar disorder, were selected. Studies of participants with bipolar disorder were to be included. Subjects could be of either sex and of all ages.

DATA COLLECTION AND ANALYSIS

Data extraction and methodological quality assessment were performed independently by two reviewers. For analysis, relative risk was used for binary efficacy outcomes and the weighted mean difference or standardised mean differerence was used for continuously distributed outcomes

MAIN RESULTS

We did not find any studies which fulfilled the Cochrane criteria of randomised controlled trials. However, one uncontrolled open label study and one case series were found. There were also three case reports/series of acute treatment which were continued into maintenance therapy, and one open non-randomised study with this design. The results of these studies are inconsistent.

AUTHORS' CONCLUSIONS

We found no randomised controlled trials of tiagabine in bipolar disorder. In the reported cases, a significant proportion of patients suffered episodes of syncope or seizure. There is a need for randomised controlled trials examining the efficacy and acceptability of tiagabine in the acute treatment of bipolar disorder, after the nature of these episodes has been clarified.

Retrospective evaluation of tiagabine overdose

BACKGROUND

Tiagabine is an anticonvulsant that blocks reuptake of the inhibitory neurotransmitter GABA. There are no published studies or case series of tiagabine overdoses.

METHODS

The records of six poison centers and one statewide poison center network were searched for all exposures to tiagabine for the years 2000-2002. Inclusion criterion was a human tiagabine exposure with follow-up to a known outcome; exclusion criterion was multiple drug ingestion.

RESULTS

57 cases met the inclusion criterion. Thirty-seven patients were female (67%). Mean and median ages were 30.5 years (S.D. +/- 18.5) and 31 years, respectively, with a range of 2 to 80 years. Seven patients were < or = 6 years. Neurologic symptoms were common: lethargy, seizures (multiple), status epilepticus, seizure (single), coma, confusion, agitation, tremors, dizziness, dystonias/abnormal posturing, and hallucinations. Other symptoms included respiratory depression, tachycardia, hypertension, and hypotension. Therapies included benzodiazepines, mechanical ventilation, phenytoin, phenobarbital, diphenhydramine, and dopamine. The mean onset and duration of symptoms were 1.3 hours (+/- 0.5, range 1-2 hours) and 9.1 hours (+/- 3.8, range 4-24 hours), respectively. Dose ingested by history was known for 38 patients (67%). The lowest dose with the development of multiple seizures and coma was 96 mg. This occurred in a 36-year-old female with a history of epilepsy. The lowest dose with symptoms in a child was 8 mg, in a 6-year-old with drowsiness. Mean dose of those with and without symptoms was 102 mg and 10 mg, respectively. The mean dose for patients experiencing seizures was 224 mg (+/- 172, range 96 to 680 mg). The mean dose for patients experiencing coma and respiratory depression was 270 mg (+/- 204, range 96 to 680 mg). Fifty-two patients (91%) were evaluated in the ED of whom 43 were admitted for medical care.

CONCLUSION

Seizures and altered mental status were common with tiagabine overdose, with rapid onset and resolution of symptoms. In this series, seizures did not occur until the ingestion was greater than three times the maximum recommended daily dose.

Status Epilepticus and Tiagabine Therapy Revisited

PURPOSE

To determine whether antiepileptic treatment with tiagabine (TGB) is associated with an increased frequency of nonconvulsive status epilepticus (NCSE) in patients with refractory epilepsy.

METHODS

We reviewed retrospectively the medical and EEG records of all inpatients with refractory localization-related epilepsy at the National Society for Epilepsy treated with TGB between January 1997 and December 2000. Clinical and electroencephalographic (EEG) data before, during, and after TGB therapy were evaluated in those patients who experienced a deterioration in seizure control suggestive of NCSE. Frequency of NCSE was determined in a comparable, non-TGB-treated patient population.

RESULTS

Seven (7.8%) of 90 TGB-treated patients were identified who experienced episodes of electroclinically confirmed NCSE. Serial EEGs showed deterioration during TGB treatment, with resolution of abnormality on discontinuation of TGB in all seven patients. During the same observation period, 32 (2.7%) of 1,165 non-TGB-treated patients developed electroclinically defined NCSE.

CONCLUSIONS

Treatment with TGB is associated with an increased frequency of NCSE in patients with refractory localization-related epilepsy.

Acute management of seizures in the syndromes of idiopathic generalized epilepsies

Three of the seizure types (myoclonic, absence, and generalized tonic-clonic) and syndromes associated with idiopathic generalized or genetic epilepsies can present an acute status epilepticus picture that requires acute therapy. These are not the usual seizures observed in status epilepticus because most of these patients have secondary generalized or symptomatic generalized convulsive seizures. In this review, I discuss the unique presentation and treatment options for the acute management of seizures in the syndromes of idiopathic generalized epilepsy (IGE), with special emphasis on the seizures of status epilepticus, which persist over time or occur in a series without recovery of consciousness.

Nonconvulsive status epilepticus due to a de novo contralateral focus during tiagabine adjunctive therapy

We describe a 30-year-old woman with an infantile-onset epilepsy due to a left temporal gliotic area who developed a nonconvulsive status epilepticus (NCSE) during tiagabine (TGB) adjunctive therapy. The ictal EEG recording showed a de novo right temporal focus not previously evident. After the i.v. administration of 4 mg lorazepam, the NCSE episode rapidly resolved and her usual left temporal EEG abnormalities reappeared. To our knowledge this is the first case of paradoxical seizure exacerbation associated with TGB therapy in which the clinical and EEG features are congruous with a new contralateral focus.

Clinical and EEG findings in six patients with altered mental status receiving tiagabine therapy

Tiagabine (TGB), a novel GABA reuptake inhibitor antiepileptic drug, has been reported to induce nonconvulsive status epilepticus (NCSE) in patients with generalized or partial onset seizures. We describe six patients with refractory partial epilepsy treated with add-on TGB. They developed acute intermittent or progressive chronic confusion associated with diffuse slowing of the electroencephalogram (EEG), shortly after an increase in dose of TGB. This remitted in each situation after reduction of the daily dose. The possibility of nonconvulsive status epilepticus or toxic encephalopathy is discussed.