For a patient suspected of taking beta blockers, which medication is indicated?

In cases where a patient is suspected of taking beta blockers, glucagon is indicated due to its unique pharmacological action. Beta blockers can lead to decreased heart rate and potential hypotension because they block the effects of adrenaline on the beta-adrenergic receptors of the heart and vascular system. Glucagon works by increasing blood sugar levels and stimulating the heart through non-adrenergic pathways, which is especially beneficial in counteracting the bradycardic and hypotensive effects of beta blockers.

When glucagon is administered, it promotes cardiac contractility and can help improve heart rate, particularly in scenarios where conventional treatments like epinephrine may be ineffective. This is due to the unresponsive nature of beta-blocked beta receptors. The rapid action of glucagon can quickly stabilize the patient while other measures are taken.

The other options listed do not serve as effective countermeasures against the effects of beta blockers. Calcium gluconate is typically used in situations involving acute hyperkalemia or calcium channel blocker overdoses, flumazenil is a benzodiazepine antagonist which would not address beta blocker toxicity, and amyl nitrite is primarily utilized in cases of cyanide poisoning, not in beta blocker scenarios.