Which anesthetic mixture is no longer available in North America?

The anesthetic mixture that is no longer available in North America is fentanyl and droperidol. This combination was once used for sedation and anesthesia, particularly in certain surgical contexts. However, droperidol faced significant scrutiny over safety concerns, particularly related to its potential to cause serious side effects, including QT prolongation, which can lead to life-threatening cardiac arrhythmias.

As a precautionary measure, regulatory bodies withdrew droperidol from the market in many regions, including North America. As a result, the combination with fentanyl, which was commonly utilized in various anesthesia practices, also became unavailable.

In contrast, the other options presented involve combinations that remain in use or are not subject to the same regulatory challenges that led to the withdrawal of fentanyl and droperidol. Understanding the implications of drug safety and regulatory actions is crucial in the field of anesthesia, as these factors can directly influence clinical practice and availability of anesthetic agents.