Which of the following barbiturates is classified in controlled substances category IV?

Phenobarbital is classified as a controlled substance in Category IV. This classification indicates that it has a recognized medical use but also carries a risk of dependence and abuse. Phenobarbital is commonly used as an anticonvulsant and for sedation, making it important in treating seizure disorders and anxiety, but it is monitored carefully due to its potential for misuse.

Secobarbital, amobarbital, and butalbital are barbiturates that are typically classified under more restrictive categories due to their higher potential for abuse and dependence. While they also have medical applications, the risks associated with their use have led to stricter regulations compared to phenobarbital. Understanding the classification of these substances highlights the importance of managing medications with potential for abuse in a manner that ensures both patient safety and therapeutic effectiveness.