What is tachyphylaxis?

Tachyphylaxis refers to a rapid decrease in the response to a drug after its administration. This phenomenon typically occurs after the repeated administration of a drug over a short period of time, resulting in a decreased effectiveness of the drug. In this context, the correct choice highlights the concept of increased tolerance to a drug, which is characterized by the body’s adaptation to the presence of the drug.

When drugs are administered continuously or repeatedly, the body's receptors may become less responsive, leading to a diminished pharmacological effect. This tolerance builds quickly, which differentiates tachyphylaxis from regular tolerance that might develop more gradually. Understanding this concept is essential in both clinical settings and pharmacology, as it impacts dosing regimens and the effectiveness of treatment protocols.