**Core Concept**
Fospropofol is a water-soluble prodrug of propofol, a widely used intravenous anesthetic agent. Propofol exerts its sedative and hypnotic effects through potentiation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) at the GABA_A receptor.

**Why the Correct Answer is Right**
Fospropofol is metabolized by alkaline phosphatase to its active form, propofol, which then acts on GABA_A receptors in the brain to induce sedation and hypnosis. The conversion of fospropofol to propofol occurs primarily in the liver, but also in other tissues. This unique pharmacokinetic profile allows for a more predictable and sustained release of propofol.

**Why Each Wrong Option is Incorrect**
**Option A:** Fospropofol has a longer duration of action compared to propofol. This is incorrect because fospropofol has a shorter duration of action than propofol due to its rapid conversion to the active form.

**Option B:** Fospropofol is primarily metabolized by the liver. This statement is correct, but let's evaluate the other options first.

**Option C:** Fospropofol has a lower risk of propylene glycol toxicity compared to propofol. This statement is incorrect because fospropofol is still metabolized to propofol, which can cause propylene glycol toxicity, especially in high doses.

**Option D:** Fospropofol is used for the induction and maintenance of general anesthesia. This statement is correct, but let's confirm the correct answer.

**Clinical Pearl / High-Yield Fact**
Fospropofol is a useful alternative to propofol in patients with renal or hepatic dysfunction, as it does not rely on renal or hepatic metabolism for its conversion to the active form.

**Correct Answer:** B. Fospropofol is primarily metabolized by the liver.