**Question:** Which of the following is not a side effect of naloxone?

A. Depression of respiratory center
B. Increased heart rate
C. Reduced cerebral blood flow
D. Increased salivary secretion

**Core Concept:** Naloxone is a synthetic opioid antagonist used to reverse the effects of opioid overdose. It works by binding to opioid receptors and blocking the effects of endogenous opioids like endorphins and morphine.

**Why the Correct Answer is Right:** Naloxone primarily targets mu-opioid receptors, leading to the suppression of respiratory center and increased heart rate as its side effects. However, it does not directly affect cerebral blood flow or salivary secretion, making "reduced cerebral blood flow" (option C) and "increased salivary secretion" (option D) incorrect side effects of naloxone.

**Why Each Wrong Option is Incorrect:**

- "Reduced cerebral blood flow" is not a side effect of naloxone because it does not directly influence the brain or blood vessels involved in cerebral circulation.
- "Increased salivary secretion" is also not a side effect of naloxone, as this effect is a result of direct stimulation of parasympathetic nerves by opioids, not a consequence of naloxone's action on opioid receptors.

**Clinical Pearl:** When administering naloxone, it is essential to monitor the patient closely for respiratory depression as this is the primary action of naloxone aimed at reversing opioid overdose effects.

**Correct Answer:** C. Reduced cerebral blood flow