What does metabolic tolerance refer to in drug use?

Metabolic tolerance specifically refers to the process where the body's metabolic system, particularly the liver, adapts to the presence of a drug by increasing the production of enzymes responsible for breaking down that drug. When an individual regularly consumes a substance, the liver becomes more efficient at metabolizing it, meaning that higher doses may be required to achieve the same effect that was once experienced with a lower dose. This adaptation can lead to individuals needing to consume more of the drug over time to experience its effects, as their bodies have become accustomed to the drug's presence.

This concept is a key part of understanding how tolerance develops in substance use, as it highlights the biochemical changes occurring in the body rather than psychological or behavioral adaptations.