Final answer:
Cross-tolerance with CNS depressants is not uncommon; it occurs when tolerance to one drug causes a tolerance to another within the same class, often due to similar mechanisms of action in the brain. The correct option is b).
Step-by-step explanation:
Is cross-tolerance uncommon with CNS depressants? The answer is b) False. Cross-tolerance is a phenomenon that occurs when tolerance to the effects of one drug causes a tolerance to another drug within the same class.
With regards to central nervous system (CNS) depressants, such as alcohol, benzodiazepines, and barbiturates, cross-tolerance is not uncommon. This means that if a person develops tolerance to one CNS depressant, they may exhibit a certain level of tolerance to another CNS depressant even if they have not consumed it before.
The reason cross-tolerance develops is that many CNS depressants act on similar pathways in the brain, often affecting the neurotransmitter GABA. Drugs like alcohol and benzodiazepines, for instance, both activate GABA receptors, which contributes to their depressant effect.
This similar mechanism of action leads to cross-tolerance. It's important to understand that this cross-tolerance can be a potential risk factor for overdose if individuals switch between substances without adjusting dosages accordingly. Option b) is the correct one.