**Core Concept**
Postoperative shivering is a common complication that can occur after anesthesia, caused by the body's response to cold stress, pain, or other factors. It can increase oxygen consumption, heart rate, and blood pressure, leading to potential complications such as hypoxia, cardiac arrhythmias, and increased postoperative pain.

**Why the Correct Answer is Right**
The drug of choice for treating postoperative shivering is meperidine (pethidine), a centrally acting opioid that works by inhibiting the release of norepinephrine, a neurotransmitter that stimulates the hypothalamus, leading to shivering. Meperidine also has analgesic properties, which can help to reduce pain and discomfort. The recommended dose is 1-2 mg/kg IV, titrated to effect.

**Why Each Wrong Option is Incorrect**
**Option A:** **Lidocaine** - Lidocaine is a local anesthetic that works by blocking sodium channels, and is not effective in treating postoperative shivering.

**Option B:** **Dantrolene** - Dantrolene is a muscle relaxant that works by inhibiting calcium release from the sarcoplasmic reticulum, but is not typically used to treat postoperative shivering.

**Option C:** **Clonidine** - Clonidine is an alpha-2 adrenergic agonist that can be used to treat hypertension, ADHD, and withdrawal symptoms, but is not the first-line treatment for postoperative shivering.

**Clinical Pearl / High-Yield Fact**
Meperidine should be used with caution in patients with renal impairment, as it can cause accumulation of the metabolite normeperidine, which can lead to seizures and other CNS effects.

**Correct Answer:** C. Dantrolene