HomeMedicine & HealthPharmacologyWhat is Tolerance?
Medicine & Health·2 min·Updated Mar 12, 2026

What is Tolerance?

Tolerance

Quick Answer

Tolerance is the body's reduced response to a drug or substance after repeated use. This means that over time, a person may need to take more of the substance to achieve the same effect.

Overview

In pharmacology, tolerance occurs when a person's body becomes accustomed to a drug, leading to diminished effects. This adaptation happens because the body tries to maintain balance, adjusting its chemistry in response to the drug's presence. For example, someone taking pain medication may find that over time, the same dose no longer relieves their pain as effectively as it used to. The mechanism behind tolerance involves changes in the brain and body that affect how a drug works. Repeated exposure can lead to a decrease in the number of receptors available for the drug or alterations in the way the drug is processed. This means that the body is essentially working harder to counteract the drug's effects, which can complicate treatment and lead to increased dosages. Understanding tolerance is important for healthcare providers when prescribing medications. They need to monitor patients closely to avoid potential issues like overdose or dependency. For instance, in cases of chronic pain management, a doctor may need to adjust the medication regimen to ensure the patient continues to receive effective pain relief without increasing the risk of tolerance.


Frequently Asked Questions

Tolerance develops due to the body's adaptation to a drug after repeated use. The body may change its chemistry or reduce the number of receptors to counteract the drug's effects.
No, tolerance and addiction are different. Tolerance refers to the body's reduced response to a drug, while addiction involves a psychological or physical dependence on the substance.
Yes, tolerance can often be reversed by reducing or stopping the use of the drug. This allows the body to readjust and regain sensitivity to the substance.