Signs of Bupropion Overdose
Seizures are the hallmark of bupropion overdose, occurring in approximately one-third of all cases, with other serious manifestations including hallucinations, altered mental status, sinus tachycardia, and cardiac conduction abnormalities. 1
Primary Clinical Manifestations
Neurological Effects
The most critical and common neurological signs include:
- Seizures (27-33% of overdoses) - can be delayed up to 24 hours post-ingestion, with 32% of initial seizures occurring >8 hours after ingestion 1, 2
- Altered mental status - ranging from agitation to loss of consciousness 1
- Hallucinations (28.6% in overdose) 3
- Clonus and myoclonus 1
- Hyperreflexia 1
- Tremors (40.5% in patients who seize) 2
Cardiovascular Effects
Cardiac manifestations follow a dose-dependent pattern:
- Sinus tachycardia - most common cardiac finding 1, 4
- ECG changes including conduction disturbances, prolonged QTc and QRS intervals 1, 4
- Arrhythmias 1
- Paradoxical bradycardia - seen with massive overdoses (>13g), typically appearing 4-8 days post-ingestion 4
- Hypotension and potential progression to cardiogenic shock in severe cases 1, 5
Other Serious Effects
Additional life-threatening manifestations include:
- Fever and muscle rigidity 1
- Rhabdomyolysis 1
- Stupor and coma 1
- Respiratory failure 1
- Cardiac arrest - reported in fatal cases with multiple uncontrolled seizures 1
Risk Stratification by Dose
The severity correlates with ingested amount:
- <900 mg: Generally mild outcomes, home management may be appropriate in select patients 6
- 600-3000 mg: Seizure risk present (median 900 mg in seizure cases) 2, 6
- >13.5g: Massive overdose with atypical findings including delayed bradycardia and hepatotoxicity 4
Temporal Considerations
Critical observation period: minimum 24 hours 2
- Seizures can occur 0.5-24 hours post-ingestion
- 32% of initial seizures occur >8 hours after ingestion 2
- Delayed effects (14-28 hours) are rare but documented 7
- Heart rate >104 bpm within 8 hours has 100% negative predictive value for delayed adverse effects 7
Important Clinical Caveats
Seizures can occur without preceding CNS symptoms - while agitation (p=0.045) and tremors (p=0.005) are more frequent in patients who develop seizures, their absence does not exclude seizure risk 2
Serotonin syndrome can occur despite bupropion lacking direct serotonergic activity, likely through indirect mechanisms 8
Pediatric vulnerability - children as young as 1.3 years have developed seizures; adolescents show significantly higher morbidity and mortality with bupropion compared to SSRIs (0.23% vs 0% death rate) 3, 2
Management Implications
There are no known antidotes for bupropion overdose 1. Management is purely supportive with:
- Close medical supervision and monitoring
- Benzodiazepines for seizure control (required in 34.2% of overdoses) 3
- Intubation (4.9% of cases) 3
- Vasopressor support (1.1% of cases) 3
- CPR readiness (0.51% of cases) 3
Multiple uncontrolled seizures, bradycardia, cardiac failure, and cardiac arrest have been reported prior to death in fatal cases 1, emphasizing the need for aggressive supportive care and ICU-level monitoring in significant overdoses.