From the Research
The toxic dose of propranolol is generally considered to be around 2,000 mg in adults, as severe toxicity was common in isolated propranolol ingestions at or above this dose, with half of the patients who ingested ≥2,000 mg experiencing severe toxicity 1.
Key Factors Influencing Toxicity
- The patient's age, weight, and cardiac function can affect the severity of propranolol toxicity
- Underlying conditions, such as asthma or heart block, can increase the risk of severe toxicity
- Co-ingestion of other substances, like benzodiazepines, can also impact the severity of propranolol overdose
Clinical Manifestations of Propranolol Toxicity
- Bradycardia (heart rate <50 beats/min) and hypotension (systolic blood pressure <90 mmHg) are common presentations
- Seizures, coma, and cardiac arrest can occur due to the drug's beta-blocking effects and its ability to cross the blood-brain barrier
- Extended-release formulations can lead to delayed and prolonged toxicity
Treatment and Management
- Intensive supportive care is typically required, with specific antidotes like glucagon sometimes needed
- Anyone suspecting propranolol overdose should seek immediate medical attention, as symptoms can progress rapidly
- The use of syrup of ipecac for decontamination is not recommended, as it can be associated with cardiorespiratory arrest 2