All of the following about thiopentone are true except?
**Core Concept**
Thiopentone is a **barbiturate** used for induction of anesthesia due to its rapid onset of action. It acts on the **GABA_A receptor**, enhancing the inhibitory effects of **gamma-aminobutyric acid (GABA)**, leading to sedation and anesthesia. This action is central to its therapeutic and side effects.
**Why the Correct Answer is Right**
Since the options are missing, let's focus on thiopentone's properties: it has a high lipophilicity, which allows it to quickly cross the **blood-brain barrier**, resulting in rapid induction of anesthesia. Thiopentone is metabolized by the **liver**, and its effects are terminated through redistribution to peripheral tissues and eventual hepatic metabolism.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, we can't address it directly, but any statement contradicting thiopentone's known properties, such as its rapid onset or use in anesthesia, would be incorrect.
**Option B:** Similarly, any option misstating its mechanism, like not involving **GABA_A receptors**, would be wrong.
**Option C:** An incorrect statement about its metabolism or redistribution might claim it's primarily excreted unchanged by the kidneys.
**Option D:** A false claim about its lack of use in specific medical procedures or a misstatement about its pharmacokinetics would also be incorrect.
**Clinical Pearl / High-Yield Fact**
Thiopentone's rapid redistribution and metabolism make it ideal for induction but not for maintenance of anesthesia. Remember, **barbiturates** like thiopentone can cause respiratory depression, a critical consideration in their clinical use.
**Correct Answer:** Correct Answer: D. It has no analgesic properties.