Barbiturates are central nervous depressants.
They reduce the activity of nerves causing muscle relaxation. They can reduce heart rate, breathing, and blood pressure. All barbiturates affect gamma-aminobutyric acid (GABA), a neurotransmitter (chemical) that nerves use to communicate with one another.
Barbiturates are usually prescription medications. Examples of barbiturates are phenobarbital, a blood pressure medication, Nembutal, and Seconal.
For more information on barbiturates, click here.