What term describes a decreased sensitivity to a drug over time?

The term that describes a decreased sensitivity to a drug over time is tolerance. Tolerance occurs when a person's response to a medication diminishes after repeated use, leading them to require higher doses to achieve the same effect. This phenomenon is particularly common with certain classes of medications, such as opioids or sedatives, where regular use can lead to the body adapting to the presence of the drug.

In contrast, dependence refers to a state where the body has adapted to the drug, leading to withdrawal symptoms when the drug is not taken. Sensitivity, while related to how the body reacts to a substance, does not specifically denote the gradual decrease in response. An allergy is an immune response to a substance that can cause various adverse effects, but it is not related to drug sensitivity diminishing over time. Understanding tolerance is critical for appropriate medication management and ensuring patient safety in therapeutic settings.