Guidelines for Management of Accidental Double‑Dose Propranolol Ingestion

Pharmacokinetic Considerations

Extended‑release propranolol formulations can delay the onset of symptoms for up to 8 hours after ingestion, whereas cardiovascular effects usually appear within 2 hours. 1
Ingested dose of 120 mg total is far below the dose range (> 2 000 mg) associated with life‑threatening toxicity in isolated propranolol overdoses. 2

Cardiovascular monitoring: Watch for bradycardia (heart rate < 50 bpm) and hypotension (systolic BP < 90 mmHg), the most common toxic manifestations. 2
Neurological monitoring: High lipophilicity of propranolol may cause delirium, reduced consciousness, or seizures, though these are more typical at much higher doses. 1
Metabolic monitoring: Check for hypoglycemia and hyperkalemia as part of routine assessment. 1
Respiratory monitoring: Bronchospasm can occur even after cardiovascular parameters have normalized; maintain vigilance. 1
Observation period: Continuous monitoring of vital signs, electrocardiogram, and clinical status for at least 8 hours from the time of the second dose. 1
Gastric decontamination: Not indicated at this dose and when presentation occurs > 4 hours after the second ingestion. 2
IV access: Ensure reliable intravenous access for potential emergency interventions. 2

Bradycardia: Administer atropine 0.5–1 mg IV every 3–5 minutes, up to a total of 3 mg, if symptomatic bradycardia develops. 3
Hypotension: Use glucagon as first‑line therapy—initial bolus 50–150 µg/kg IV, followed by a continuous infusion of 1–5 mg/h to provide positive chronotropic and inotropic effects. 3

If the patient remains asymptomatic with stable vital signs and a normal ECG after the 8‑hour observation, discharge is appropriate with clear instructions to return for any concerning symptoms. 2
Admit for continued monitoring only if any signs of toxicity (cardiovascular, neurological, metabolic, or respiratory) emerge.

Educate patients on correct medication administration to avoid accidental double dosing, especially when using extended‑release formulations. 2