Final answer:
Sodium amobarbital and sodium pentobarbital, which are part of the barbiturates class, are referred to as truth serums due to their depressant effects on the central nervous system, though this is not their medical classification.
Step-by-step explanation:
Sodium amobarbital and sodium pentobarbital are often referred to as truth serums. These substances are part of a class of drugs known as barbiturates, which act as central nervous system depressants. Their main function is to depress or reduce arousal or stimulation in various areas of the brain. They are sometimes used medically for their sedative and hypnotic effects and work as agonists of the GABA neurotransmitter system, having a calming effect on the brain. While they are occasionally referred to colloquially as truth serums due to their ability to reduce inhibitions and possibly extract information from a subject, they are not officially categorized or used as such in clinical practice.