RiteMED Metoprolol Overdosage

Metoprolol overdosage may be expected to produce effects that are mainly extensions of pharmacologic effects, including symptomatic bradycardia, severe hypotension, bronchospasm, acute cardiac failure, impaired conduction, decreased cardiac contractility, heart block, shock, and cardiac arrest.
The first manifestations of overdose occur within 20 minutes to 2 hours after metoprolol ingestion. The effects of massive overdose may persist for several days, despite decreasing plasma levels.
In cases of overdose, patients should be admitted to a hospital and should be managed in an intensive care setting, with continuous monitoring of cardiac function, blood gases, and blood chemistry. Institute emergency supportive measures (e.g., artificial ventilation, cardiac pacing) if appropriate. Patients who have taken small overdose should be closely observed for manifestations of poisoning for at least 4 hours.
In acute metoprolol overdose, immediately empty the stomach by gastric lavage and/or activated charcoal. Initiate supportive and symptomatic treatment. For symptomatic bradycardia, IV atropine may be given; if bradycardia persists, IV isoproterenol hydrochloride may be administered cautiously. A vasopressor (e.g., dopamine, dobutamine, norepinephrine) may be given for severe hypertension; IV glucagon may be useful if hypotension is refractory to vasopressors. A beta-adrenergic agonist (e.g., isoproterenol) and/or a theophylline derivative may be given for bronchospasm. Monitor patients for evidence of cardiac arrhythmias during and after administration of the bronchodilator. Diazepam may be administered to control seizures. For heart failure, a cardiac glycoside, diuretic, and oxygen should be used; IV glucagons may also be useful.