Which of the following β – blocker has membrane stabilizing action
**Core Concept**
Membrane stabilizing action refers to the ability of certain β-blockers to inhibit the sodium channels in the cardiac cell membrane, leading to a reduction in automaticity and contractility. This effect is distinct from their β-blocking action, which involves antagonism of β-adrenergic receptors.
**Why the Correct Answer is Right**
**Carteolol** has a unique property among β-blockers, which is its inherent membrane stabilizing action. This is due to its ability to block sodium channels, similar to Class I antiarrhythmic drugs. This effect contributes to its antiarrhythmic properties, particularly in the management of supraventricular tachycardia and Wolff-Parkinson-White syndrome.
**Why Each Wrong Option is Incorrect**
**Option A:** **Nadolol** is a non-selective β-blocker, primarily used for its β-blocking action, without significant membrane stabilizing effects.
**Option B:** **Metoprolol** is a selective β1-blocker, used primarily for its β-blocking action, without significant membrane stabilizing effects.
**Option C:** **Propranolol** is a non-selective β-blocker, used primarily for its β-blocking action, without significant membrane stabilizing effects.
**Clinical Pearl / High-Yield Fact**
When choosing a β-blocker for a patient with a history of arrhythmias or cardiac conduction abnormalities, it's essential to consider the potential for membrane stabilizing action, as this can influence the risk of proarrhythmia.
**Correct Answer:** C. Carteolol