Which term describes tolerance to one drug causing increased tolerance to another drug in the same class?

Which term describes tolerance to one drug causing increased tolerance to another drug in the same class?

• A. Cross-dependence
• B. Tolerance
• C. Cross-tolerance
• D. Metabolic tolerance

Answer: (C)

Cross-tolerance is the phenomenon where becoming tolerant to one drug in a class leads to reduced responsiveness to another drug in the same class. This happens because the drugs share similar targets or downstream adaptations in the body. For example, chronic exposure to alcohol can produce tolerance not only to alcohol but also to other sedatives like benzodiazepines, meaning a dose that would usually produce a given effect may be less effective in someone with alcohol tolerance. The other terms don’t describe this pattern: general tolerance refers to decreased response to the same drug after repeated use, cross-dependence concerns needing one drug to manage withdrawal from another, and metabolic tolerance involves changes in how the body metabolizes drugs, not the cross-drug responsiveness within the same class. This concept is cross-tolerance.

Cross-tolerance is the phenomenon where becoming tolerant to one drug in a class leads to reduced responsiveness to another drug in the same class. This happens because the drugs share similar targets or downstream adaptations in the body. For example, chronic exposure to alcohol can produce tolerance not only to alcohol but also to other sedatives like benzodiazepines, meaning a dose that would usually produce a given effect may be less effective in someone with alcohol tolerance. The other terms don’t describe this pattern: general tolerance refers to decreased response to the same drug after repeated use, cross-dependence concerns needing one drug to manage withdrawal from another, and metabolic tolerance involves changes in how the body metabolizes drugs, not the cross-drug responsiveness within the same class. This concept is cross-tolerance.