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Chapter 7 Chapter 7

Depressants and Depressants and

Inhalants Inhalants

Depressants Depressants

 Depressants = drugs that slow activity in

the central nervous system

 (^) Include prescription drugs that treat anxiety

(sedatives) and insomnia (hypnotics)

 (^) As a group, also called sedative-hypnotics  (^) Alcohol is the most widely used depressant  (^) Benzodiazepines are the most widely

prescribed depressants

History: Before Barbiturates History: Before Barbiturates

 (^) Chloral hydrate (“knockout drops,” “Mickey Finn”)

 Synthesized in 1832; used clinically in 1870

 Induces sleep in less than an hour

 Abuse leads to gastric irritation

 (^) Paraldehyde

 Synthesized in 1829; used clinically in 1882

 Effective with a wide safety margin

 Noxious taste and odor

 (^) Bromides

 Widely used as a sleep agent in patent medicines;

appeared in OTC drugs through the 1960s

 Can accumulate in the body and cause toxic effects

Barbiturates Barbiturates

 (^) Discovery/introduction

 1903: Barbital (Veronal) became the first barbiturate to

be used clinically

 Other popular barbiturates include phenobarbital,

amobarbital and secobarbital  (^) Grouped on the basis of the time of onset and

duration of activity

 Low-dose, long-acting forms used for daytime relief of

anxiety

 Higher-dose, shorter-acting forms used to induce

sleep

Sodium Pentathol Sodium Pentathol

 (^) Ultra-short acting barbiturate  (^) Administered intravenously  (^) Used as an anesthetic for brief surgical

procedures

 (^) Moves very rapidly into the brain  (^) Also used to make people relaxed and talkative

(truth serum)

 (^) Thiopental is currently the first of the three drugs

administered for the death penalty

Meprobamate Meprobamate

 The first modern antianxiety agent

(anxiolytic)

 Widely prescribed beginning in the 1950s

 Like barbiturates, can produce

psychological and physical dependence

 Still available as a prescription drug,

although largely replaced by

benzodiazepines

Benzodiazepines Benzodiazepines

 (^) 1960: Introduction of chlordiazepoxide (Librium),

the first commercially marketed benzodiazepine

 Reduces anxiety without inducing sleep

 Much larger safety margin than barbiturates

 Physical dependence rare

 Overdose rare and usually only when combined with

other depressants like alcohol  (^) 1970s: Diazepam (Valium), a lower-dose

benzodiazepine, became for a time the best

seller among all prescription drugs

Benzodiazepines Benzodiazepines

 (^) Dependence and overdose can occur; dosage

and time course are critical factors

 Overdose deaths more likely for drugs sold in higher

doses

 Psychological dependence more likely with drugs that

have a rapid onset of effects

 Physical dependence more likely with drugs that have

a short duration of action  (^) More differences among the barbiturates and

among the benzodiazepines than there are

between these two classes of drugs?

Mechanism of Action Mechanism of Action

 (^) Benzodiazepines and barbiturates

 Bond with brain receptors

 Enhance the normally inhibitory effects of GABA

 (^) Nonbenzodiazepine hypnotics

 Selectively target the GABA-A receptor

 Seem to work better as sleeping pills than as

antianxiety drugs

 Include zolpidem (Ambien), zaleplon (Sonata), and

eszopiclone (Lunesta)

Beneficial Uses: Summary Beneficial Uses: Summary

 AnxiolyticsAnxiolytics

 As sleeping agentsAs sleeping agents

 As anticonvulsantsAs anticonvulsants

Beneficial Uses Beneficial Uses

 (^) Concerns about use of sedatives as anxiolytics:

 Some anxiety disorders respond to anxiolytics while

others seem to be treated more effectively by antidepressants or behavior therapy

 Patients may take the drugs for long period

 Anxiolytics may be overprescribed

 (^) Is a person taking the drug to treat a disorder or to feel better in a general way?

Beneficial Uses Beneficial Uses

 (^) As sleeping pills

 Taking a large enough dose of a

hypnotic drug helps a person get to sleep more quickly

 Insomnia is a common complaint,

although people sometimes overestimate its severity

 Today, fewer hypnotics are

prescribed than in the past, and they are usually taken for only a few nights at a time

Beneficial Uses Beneficial Uses

 Nonbenzodiazepine hypnotics

 (^) Zolpidem (Ambien) binds selectively to

GABA-A receptors

 (^) Rapid onset and short duration of action  (^) Concern about people driving while still under the influence (from not allowing 8 hours of sleep after taking drug)  (^) Eszopiclone (Lunesta)  (^) Approved for long-term use

Falling Asleep Without Pills Falling Asleep Without Pills

 Have a regular sleep schedule

 When you go to bed, turn out the lights and relax

 Exercise regularly but not late in the evening

 Prepare a comfortable sleep environment in terms of

temperature and noise

 Eat a light snack before bed

 Avoid tobacco use

 If you don’t fall asleep within 30 minutes, get up and do

something relaxing before trying to fall asleep again

 Do not nap during the day

 Avoid chronic use of sleeping pills