Toxicology – Bupropion Toxicity

Source

Bupropion is a prescription medication used primarily as an antidepressant and as an aid for smoking cessation. It is available in immediate-release and extended-release formulations.

Typical Presentation

A patient with excessive bupropion exposure may initially develop agitation and tachycardia before suddenly experiencing a generalized seizure. Extended-release formulations are particularly important because serious neurological and cardiovascular effects may be delayed.

Clinical Features

Possible manifestations include:

• Agitation and restlessness
• Sinus tachycardia
• Hypertension
• Nausea and vomiting
• Lethargy or altered mental status
• Orthostatic hypotension
• Seizures, which are a major feature of toxicity
• QRS widening
• QTc prolongation
• Cardiovascular instability in severe poisoning

Seizure risk increases with greater exposure, although seizures have occasionally been reported during therapeutic use.

Mechanism of Action

Bupropion primarily inhibits the reuptake of dopamine and norepinephrine, increasing their activity within the CNS. Its effects on dopamine are particularly prominent. The medication undergoes hepatic metabolism and has active metabolites that may contribute to prolonged toxicity.

Management

Treatment is primarily supportive:

• Maintain and protect the airway when necessary
• Continuous cardiac and neurological monitoring
• Benzodiazepines are first-line treatment for seizures
• Manage status epilepticus aggressively if it develops
• Monitor ECG for QRS and QT abnormalities
• Gastrointestinal decontamination may be considered in selected significant exposures
• Severe cardiovascular toxicity may require advanced toxicology-directed supportive therapies

Extended-release overdoses generally require prolonged observation because seizures and cardiovascular complications can occur after a substantial delay.

Key Points

• Seizures are a hallmark of bupropion toxicity.
• Extended-release preparations can produce delayed seizures.
• ECG abnormalities may include QRS widening and QTc prolongation.
• Severe poisoning can progress from agitation and tachycardia to seizures, altered consciousness, and cardiovascular collapse.