When the body repeatedly encounters a substance, it adapts, reducing the substance’s effect. This diminished response, known as drug tolerance, necessitates higher doses over time to achieve the same desired outcome.
Drug tolerance manifests in two primary forms:
-
Pharmacodynamic Tolerance: The body’s cells become less responsive to the drug. This occurs due to various mechanisms, including changes in receptor sensitivity or number, or alterations in the drug’s metabolic process.
-
Metabolic Tolerance: The body efficiently metabolizes the drug, resulting in lower blood levels. Increased enzyme activity breaking down the drug or changes in its transport to and from the brain can cause this.
Drug tolerance poses significant challenges for individuals managing chronic conditions. It hinders symptom control and often necessitates higher medication doses, increasing the risk of side effects.