Which of the following is antidote for beta-blocker poisoning?
## **Core Concept**
Beta-blocker poisoning leads to excessive blockade of beta-adrenergic receptors, causing symptoms like bradycardia, hypotension, and bronchospasm. The management involves administering an antidote that can counteract these effects. The antidotes for beta-blocker poisoning work by increasing heart rate, contractility, and vascular tone.
## **Why the Correct Answer is Right**
The correct answer, **Glucagon**, is an antidote for beta-blocker poisoning because it increases heart rate and contractility without relying on beta-adrenergic receptors. Glucagon acts through a different pathway, increasing intracellular cyclic AMP (cAMP) levels, which enhances cardiac contractility and heart rate. This makes glucagon effective in treating the cardiovascular manifestations of beta-blocker overdose.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because, although **Atropine** can be used to treat some symptoms of beta-blocker poisoning like bradycardia, it does not effectively counteract the negative inotropic effects (decreased heart muscle contractility) and is not considered a primary antidote.
- **Option B:** This option is incorrect as there is no commonly recognized antidote for beta-blocker poisoning listed here; **Lidocaine** is sometimes used in cardiac emergencies but is not a primary antidote for beta-blocker overdose.
- **Option C:** This option is incorrect because **Sodium bicarbonate** may be used in certain cases of drug overdose (like tricyclic antidepressants) but is not a specific antidote for beta-blocker poisoning.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that in beta-blocker poisoning, **Glucagon** is administered intravenously at a dose of 5-10 mg over 1 minute, followed by an infusion of 1-5 mg/hour. This can be particularly useful in a clinical setting where patients present with severe symptoms due to beta-blocker overdose.
## **Correct Answer:** . Glucagon