The dose of all of the following local anesthetic should be decreased in patients with deranged liver function except-
**Core Concept**
The metabolism of local anesthetics primarily occurs in the liver, where they undergo hepatic conjugation and elimination. Patients with deranged liver function may experience altered pharmacokinetics, leading to accumulation of the local anesthetic and potential toxicity.
**Why the Correct Answer is Right**
Patients with liver dysfunction may experience decreased metabolism of local anesthetics, leading to increased plasma concentrations and potential toxicity. This is particularly concerning for local anesthetics that are metabolized by the liver, such as lidocaine, mepivacaine, and bupivacaine. However, some local anesthetics, like ropivacaine, have a lower dependence on liver metabolism and are less affected by hepatic impairment.
**Why Each Wrong Option is Incorrect**
* **Option A:** Lidocaine is metabolized by the liver and its clearance is significantly reduced in patients with liver dysfunction, making a dose decrease necessary.
* **Option B:** Mepivacaine is also metabolized by the liver and its clearance is decreased in patients with liver dysfunction, requiring a dose reduction.
* **Option C:** Bupivacaine is primarily metabolized by the liver and its clearance is reduced in patients with liver dysfunction, necessitating a dose decrease.
**Clinical Pearl / High-Yield Fact**
Lidocaine, mepivacaine, and bupivacaine are all metabolized by the liver and require dose reduction in patients with liver dysfunction to prevent toxicity.
**Correct Answer: D. Ropivacaine**