Joseph Preistly & Humphrey Davy discovered and synthesized
Nitrous Oxide (laughing gas)
William Morton successfully used Ether to operate on a patient
without the conventional use of restraints
Chroloform and chloral hydrate were developed and used an
analgesics in the 1880's
Dr. Adolph von Bayer developed Barbiturates in the form of
barbituric acid (which contains urea)
Barbiturates
Had immediate appeal due to various potencies and onset
times
Tended to be abused during the '50's
Barbiturate Effects
Barbiturates act as a CNS depressant
Moderate doses produce a drunken euphoria, loss of motor
control, and slurred speech
High doses decrease respiration, heart rate and BP
If Barbiturates are injected IV or intramuscularly it causes
pain and possibly necrosis, or death of the surrounding
tissue
The absorption and effect of these drugs can often be
potentiated by the presence of aspirin, which helps to free up
bound molecules in the blood.
Barbiturates tend to have an immediate effect, producing
sedation or euphoria
Some of the drug is stored in the fat tissues and slowly
released, causing prolonged "hangover" effectsBarbiturate
Effects
A mother given barbiturate sedation during birth may give have
a lethargic infant, called the floppy baby syndrome
Tolerance/Dependence
Tolerance develops rapidly
Withdrawal is similar to that of alcohol
Even mild doses are capable of producing insomnia when the
drug is stopped and REM rebound
The barbiturates can be lethal, especially when combined with
alcohol
Non-Barbiturate Sedatives
Quaaludes (methaqualone) and Miltown (equinol or meprobamate)
are very toxic at high doses and are generally not used for
medical purposes
Benzodiazapines
Benzodiazapines have been favored by the medical field as a
safer alternative to barbs
While barbiturates still were used to control seizures and
serve as general anesthetics, the drug of choice to control
anxiety were the bensodiazapines of the 1950's and '60's
Types of Benzodiazapines
Librium (chlodiazepoxide) - Discovered by accident. Produces
sedation, muscle relaxation, and eases anxiety. Has a very high
lethality dose
Valium ( diazepam) - fast acting drug with a high potential
for abuse
Benzo's are used to prevent vomiting, induce sleep, prevent
seizures, and ease anxiety
How Depressants Work
Both barbiturates and benzodiazapines exert similar
physiological action
Benzodiazapines seem to have their own receptors in the brain
and throughout the nervous system
Both drugs bind near GABA receptors, the inhibitory amino acid
neurotransmitter. They then enhance the inhibitory effects of this
transmitter
GABA receptors play a role in memory processing, so both
classes of drugs are capable of producing anterograde amnesia
Both may also cause a psychosis-like state at high doses
Barbiturates are slowly metabolized, generally because they
are lipid soluable and tend to be re-absorbed by the kidneys
The metabolites of some benzodiazapines form other sedating
substances (e.g., valium, librium and tranzene all metabolize into
serax, or oxazapam).
These metabolites extend the half-life to 1 - 2 DAYS, which is
a potential problem with the drug, as it toxicity may occur, or
potentiation/drug interaction