Life-threatening adverse drug reactions causing - seizures

Description

Drug-induced seizures arise through lowered seizure threshold (many drug classes have some pro-convulsant potential, particularly at supratherapeutic doses or in overdose) or through specific mechanisms (e.g. tramadol and bupropion's serotonergic/dopaminergic effects, tricyclic antidepressant sodium channel blockade in overdose) - recognising a drug cause matters since standard anti-seizure medication may be less effective than treating the underlying drug-specific mechanism

A recognised complication across a broad range of drug classes and overdose scenarios, with certain agents (tramadol, bupropion, tricyclic antidepressants, and drug withdrawal states - particularly alcohol/benzodiazepine withdrawal) carrying disproportionately elevated seizure risk compared with other medications

Several distinct mechanisms converge on seizure generation - direct lowering of the seizure threshold through altered neurotransmitter balance (e.g. excess serotonergic/noradrenergic activity), sodium channel blockade in tricyclic overdose (also explaining the characteristic QRS widening seen alongside seizures in this specific overdose), and rebound CNS hyperexcitability in sedative/alcohol withdrawal after chronic GABA-potentiating drug exposure

ECG assessment is particularly relevant in suspected tricyclic antidepressant overdose, since QRS widening from sodium channel blockade both predicts seizure/arrhythmia risk and guides specific treatment (sodium bicarbonate)
Identifying the causative drug/mechanism (overdose, withdrawal, or standard-dose idiosyncratic threshold lowering) directs whether standard anti-seizure treatment or a drug-specific antidote/intervention is the more effective approach

Standard first-line seizure management (benzodiazepines) applies broadly, but tricyclic antidepressant overdose-associated seizures and arrhythmias are specifically treated with sodium bicarbonate (correcting the underlying sodium channel blockade mechanism), not simply escalating anti-seizure medication alone
Alcohol/benzodiazepine withdrawal seizures are managed with benzodiazepines as both treatment and, via a symptom-triggered regimen, prevention of further withdrawal seizures

Tricyclic antidepressant overdose (QRS widening, seizures, arrhythmias - sodium bicarbonate as specific treatment), tramadol and bupropion's disproportionate seizure risk relative to other agents in their respective classes, alcohol/benzodiazepine withdrawal seizures

Sodium bicarbonate, not simply escalating standard anti-seizure medication, is the specific treatment for tricyclic antidepressant overdose-associated seizures and arrhythmias - it directly addresses the underlying sodium channel blockade mechanism (narrowing the QRS and reducing arrhythmia/seizure risk), making this a mechanism-targeted treatment distinct from generic seizure management

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