Beta blocker toxicity
Propranolol and sotalol = 'one pill can kill'
| Be especially careful of co-ingestions of other cardiotoxic drugs e.g. CCBs | |
|---|---|
| Clinical presentation | Bradycardia, hypotension, ↓ G |
| Mechanism - Sodium channel blocking effects (resembling Tricyclic antidepressant toxicity) - Hypoglycaemia: -- ↓ pancreatic glucagon release -- ↓ adrenaline counter-regulation -- |
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| Pharmacokinetics | Absorption Distribution peak 1-3h; propranolol = very lipophilic Metabolism **Eliminati |
| Diagnostic investigations | ECG: ⚠️ QRS widening → VT, VF, asystole Hypoglyc |
| Management | Supportive Observation 6h (12h if modified re |
management
airway/breathing
- hyperventilation → aiming pH 7.5
circulation
- QRS prolongation - bicarb
- ventricular arrhythmias - bicarb
- bradycardias - atropine, isoprenaline
- sotalol can cause torsades des pointes → magnesium
- severe hypotension, heart failure or cardiogenic shock - glucagon
- 5-10mg (adult), bolus then infusion if needed
- 50-150mcg/kg (paed)
| Cardiac arrest, VT or QRS ≥ 160 msec | Administer a rapid bolus of 100 mmol (i.e.100 mL 8.4%) sodium bicarbonate urgently. A repeat bolus may be administered if there is persistent QRS prolongation or arrhythmias and the pH is <7.5. |
| QRS 120-160 msec | Administer 50 mmol (i.e. 50 mL 8.4%) sodium bicarbonate. A repeat bolus may be administered if there is persistent QRS prolongation |
| Children with QRS prolongation | Administer 1-2 mL/kg 8.4% (centrally) or 2-4 mL/kg 4.2% (peripherally): If cardiac arrest or VT – as a bolus If prolonged QRS alone – over 20 minutes |
disability
seizures after propranolol overdose → high risk VT
→ give bicarb - 50ml of 8.4%
metab acidosis - consider high insulin euglycaemic therapy after disucsison with NPIS