Medication Summary
Because of the nature of overdoses, definitive evidence-based recommendations are limited. However, commonly used agents include crystalloids, atropine, pressors with catecholamine action, glucagon, and phosphodiesterase inhibitors.
Gastrointestinal Tract Decontaminants
Class Summary
These agents are used to minimize the absorption of ingested compound.
Activated charcoal (Requa Activated Charcoal, EZ-Char, Actidose-Aqua)
Although most useful if administered within 4 hours of ingestion, repeated doses may be used, especially with ingestions of sustained-released agents. Limited outcome studies exist, especially when activated charcoal is used more than 1 hour postingestion. No clinical data exist to suggest a benefit of multiple-dose activated charcoal with beta-blockers, even sustained-release preparations.
The dose may be repeated q4h at 0.5 g/kg. Alternate with use of a cathartic; monitor for active bowel sounds.
Cardiovascular agents
Class Summary
These agents are used for symptomatic bradycardia and/or hypotension. Catecholamines are considered a primary treatment for more severe cases of beta-blocker poisoning.
Atropine IV/IM (Atropine Care, Isopto Atropine)
Atropine enhances sinus node automaticity by blocking the effects of acetylcholine at the atrioventricular (AV) node, decreasing refractory time and speeding conduction through the AV node.
Glucagon (GlucaGen)
Glucagon is considered the drug of choice for beta-blocker toxicity by many authors. This agent stimulates production of cyclic adenosine monophosphate (cAMP) through nonadrenergic pathways. Result is enhanced myocardial contractility, heart rate, and AV conduction.
An upper dose limit has not been established.
Epinephrine (Adrenalin)
Agents with combined alpha- and beta-selective properties may be necessary to maintain blood pressure. A beta-agonist may competitively antagonize the effect of the beta-blocker.
The amount of beta-agonist required might be several orders of magnitude above those recommended in standard Advanced Cardiac Life Support (ACLS) protocols
Dopamine
Agents with combined alpha- and beta-selective properties may be necessary to maintain blood pressure. A beta-agonist may competitively antagonize the effect of the beta-blocker.
The amount of beta-agonist required might be several orders of magnitude above those recommended in standard ACLS protocols. In a canine model, the doses of isoproterenol and dopamine had to be increased 15 and 5 times, respectively, in order to effect similar hemodynamic changes that occurred before beta-blockade with 1 mg/kg of propranolol.
Inamrinone
Inamrinone produces vasodilation and increases the inotropic state. Tachycardia occurs more commonly with this agent than with dobutamine. Inamrinone may exacerbate myocardial ischemia. Case reports describe it as effective when other agents fail.
Calcium chloride
Calcium chloride moderates nerve and muscle performance by regulating the action potential excitation threshold. At high doses, propranolol blocks the calcium channels that may induce asystole, AV block, and depressed myocardial contraction.
Magnesium sulfate
Magnesium sulfate acts as antiarrhythmic agent and diminishes the frequency of premature ventricular contractions (PVCs), particularly those secondary to acute ischemia. This agent is used to treat torsade de pointes associated with sotalol intoxication.
Insulin regular human (Novolin, Humulin)
High-dose insulin therapy is highly investigational but should be considered when other therapies are failing.[5] Dextrose infusion of 10-75 g/h may be required. Consult a toxicologist if this regimen is considered.
Benzodiazepines
Class Summary
These agents prevent seizure recurrence and terminate clinical and electrical seizure activity.
Lorazepam (Ativan)
Benzodiazepines are considered the treatment of choice for beta-blocker–induced seizures. Of the benzodiazepines, lorazepam has the longest anticonvulsant activity (4-6 h) and is preferred. By increasing the action of GABA, which is a major inhibitory neurotransmitter in the brain, all levels of CNS, including limbic and reticular formation, may be depressed. It is important to monitor the patient's blood pressure after administering dose. Adjust as needed.
Diazepam (Valium, Diastat)
Diazepam depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA. It is considered second-line therapy for seizures.
Phenobarbital
Phonobarbital may be necessary to control status epilepticus.
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