**Question:** When the time of exposure is doubled:

A. The sensitivity to the drug increases
B. The risk of side effects decreases
C. The risk of side effects increases
D. The risk of addiction increases

**Core Concept:**
The sensitivity to a drug is influenced by the duration of exposure. Longer exposure to a medication can lead to increased sensitivity, as the body adapts or develops tolerance to the drug over time. Conversely, shorter exposure may result in decreased sensitivity (resistance).

**Why the Correct Answer is Right:**
When the time of exposure is doubled, the body adapts or develops tolerance to the drug faster. This leads to increased sensitivity (lower potency required for the drug to exert its effect). This principle is particularly relevant for opioids, which are commonly used for pain management.

**Why Each Wrong Option is Incorrect:**
A. Sensitivity does not increase when the time of exposure is doubled; it decreases as mentioned above.
B. Reduced exposure should lead to lower risk of side effects, not higher.
C. Increased exposure, not doubled, increases the risk of side effects.
D. The risk of addiction is a result of misuse and does not directly correlate with the duration of exposure to the drug.

**Clinical Pearl / High-Yield Fact:**
Understanding the relationship between drug exposure and sensitivity is crucial for effective treatment planning. For instance, in cases of chronic pain management, gradually increasing the dose over time may be necessary to maintain therapeutic efficacy, while minimizing the risk of adverse effects and addiction.