Calcium channel blockers in anaesthesia, True is –
**Core Concept**
Calcium channel blockers (CCBs) are a class of medications that inhibit the influx of **calcium ions** into cardiac and smooth muscle cells, thereby reducing muscle contraction. They are commonly used in anaesthesia to control **hypertension** and provide **cardioprotection**. CCBs can also help in reducing **anaesthetic requirements**.
**Why the Correct Answer is Right**
The correct answer is related to the effects of CCBs on the cardiovascular system, specifically their ability to cause **vasodilation** and reduce **cardiac afterload**. This is achieved through the inhibition of **L-type calcium channels** in vascular smooth muscle cells. As a result, CCBs can help in reducing **blood pressure** and improving **cardiac output**.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because CCBs do not typically cause **increased cardiac contractility**.
**Option B:** This option is incorrect because CCBs do not usually **increase anaesthetic requirements**.
**Option C:** This option is incorrect because CCBs do not typically **increase cardiac afterload**.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that CCBs can be used to control **hypertension** in anaesthesia, but they can also cause **hypotension** as a side effect.
**Correct Answer:** D. Calcium channel blockers can reduce anaesthetic requirements.