IGCSE Biology glossary
Drug tolerance
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Definition
The condition where a person needs increasing doses of a drug to achieve the same effect, because the body adapts to the presence of the drug. Tolerance develops over time with repeated use and can lead to increased consumption and greater health risks.
What to include in an exam answer
Tolerance means a higher dose is needed for the same effect. This is different from dependence (needing the drug to function normally) and addiction (compulsive drug-seeking behaviour).
Example in context
Define the term drug tolerance (1 mark): When a person needs to take a larger dose of a drug to achieve the same effect as before, because the body has become used to the drug.
Related syllabus topic
Drugs