Alcohol increasing tolerance to benzodiazepines is an example of...

Alcohol increasing tolerance to benzodiazepines is an example of...

• A. Constitutional tolerance
• B. Pharmacokinetic tolerance
• C. No interaction
• D. Cross-Tolerance

Answer: (D)

Cross-tolerance is when tolerance to one drug extends to another drug that acts on a similar system. Alcohol and benzodiazepines both enhance GABA-A receptor activity, producing greater inhibitory effects in the brain. When someone experiences chronic alcohol use, the brain adapts at the GABAergic system—changes in receptor function or subunit composition reduce responsiveness not just to alcohol but to other drugs that act on the same receptor, like benzodiazepines. So, the net effect is that higher doses of benzodiazepines are needed to achieve the same effect, illustrating a pharmacodynamic tolerance that spans to the other drug. This isn’t about drug levels or metabolism (pharmacokinetic tolerance), and it isn’t a lack of interaction.

Cross-tolerance is when tolerance to one drug extends to another drug that acts on a similar system. Alcohol and benzodiazepines both enhance GABA-A receptor activity, producing greater inhibitory effects in the brain. When someone experiences chronic alcohol use, the brain adapts at the GABAergic system—changes in receptor function or subunit composition reduce responsiveness not just to alcohol but to other drugs that act on the same receptor, like benzodiazepines. So, the net effect is that higher doses of benzodiazepines are needed to achieve the same effect, illustrating a pharmacodynamic tolerance that spans to the other drug. This isn’t about drug levels or metabolism (pharmacokinetic tolerance), and it isn’t a lack of interaction.