B

barbiturates DRUGSthat depress the functions of
the CENTRAL NERVOUS SYSTEM. Barbiturates are
SCHEDULED DRUGSin the United States, requiring a
physician’s prescription for legal use and posses-
sion. Some barbiturates are schedule 2 drugs,
which strictly limits the reasons for which physi-
cians may prescribe them.
Barbiturates readily cross the BLOOD–BRAIN BAR-
RIERonce in the BLOODcirculation and act similarly
to ALCOHOLin the ways they affect BRAINneurons.
Though researchers do not know the precise
mechanisms through which barbiturates alter
brain function, they believe these drugs cause
changes in the cell membranes of neurons in a
way that alters their action potential (ability to
transmit electrical impulses). Researchers do know
barbiturates also potentiate (enhance) the pres-

ence and activity of gamma aminobutyric acid

(GABA), a NEUROTRANSMITTERthat regulates many

of the brain’s inhibitory functions.

Excessive amounts of barbiturates in the blood

circulation suppress the respiratory centers in the

brain. Barbiturates also slow HEART RATEand lower

BLOOD PRESSURE. Combining barbiturates with alco-

hol is particularly hazardous, as these drugs act in

the same ways to depress neurologic function.

Barbiturate OVERDOSEis life threatening

and requires emergency medical care.

Signs of barbiturate overdose include

UNCONSCIOUSNESS, dilated pupils, shallow

BREATHING, and slow PULSE.

Barbiturates have numerous therapeutic uses,

including sedation during diagnostic and minor

surgical procedures, suppression of seizures, and

relief of severe anxiety. However, because barbitu-

rates have high potential for ADDICTIONand abuse,

they are seldom the first line of therapy for most

conditions except certain seizure disorders. As

drugs of abuse barbiturates are popular for the

sense of calm and well-being they can provide and

their effectiveness to induce sleep.

COMMON BARBITURATES

amobarbital aprobarbital

butabarbital butalbital

mephobarbital methohexital

pentobarbital phenobarbital

secobarbital thiopental

Suddenly stopping barbiturates after long-term

use can result in serious or lethal complications,

resulting from neurotransmitter imbalance in the

323

THE TRUTH ABOUT TRUTH SERUM

Thiopental, better known by its trade name Pen-

tothal, is a fast-acting barbiturate that produces a

trancelike state of semiconsciousness. One effect

of this state is the blockade of inhibition, allow-

ing a person to do and say what the conscious

mind might block. Psychiatrists first used sodium

pentothal expressly for this purpose when treat-

ing what was then called battle fatigue in sol-

diers returning from World War II. Psychiatrists

were able to learn the details of the traumatic

experiences the soldiers endured and provide

therapy to help them cope with their memories.

However, a person under Pentothal’s influence

does not necessarily answer questions truthfully

and indeed may sometimes tell lies once the

effect of medication removes the inhibition that

would otherwise prevent him or her from doing

so.