DepressantsBy Stephanie Rouse

Robby Gill

Depressants – aka DownersDrugs that calm and relax the central nervous system by

interfering with nerve impulse transmission

slow the function of the brain, heart, and other organs, reduce the rate of breathing, and dull emotional responses

action strongly based upon dosage of druglow dose – little or no impact

moderate dose – sedationhigh dose – induce sleep

extremely high dose – death

GABA is the main inhibitory neurotransmitter in the central nervous system (CNS). GABAergic inhibition is seen at all levels of the CNS, including the hypothalamus, hippocampus, cerebral cortex and cerebellar cortex. As well as the large well-established GABA pathways, GABA interneurones are abundant in the brain, with 50% of the inhibitory synapses in the brain being GABA mediated.

Calmness, relaxation, reduction of anxiety, sleepiness, slow breathing, slurred speech, staggering gait, poor judgment, slow, uncertain reflexesIf abused result in unconsciousness and death

TranquilizersReduce nervous tension/anxiety without inducing

sleep

Examples include:AlcoholDenzodiazepines (safer than barbituates)

Valium (diasepam) Librium

Barbiturates and benzodiazepines are the two major categories of sedative-hypnoticssimilar in chemical structure Benzodiazepine

Fusion of benzene and diazepine ring systems

Barbiturate

Barbituric Acid Ultrashort, short, intermediate, and long acting

depending upon type used to keep patient from waking before surgery is complete

Short acting are abused Similar to alcohol Thiopental ultra-short acting marketed as

Sodium Pentothal when dissolved in water in large does becomes one of the3 drugs used in the US to execute prisoners on death row, low dose used as truth serum, decreased inhibitions

Oldest depressant, 35 prescribable 5,5-disubstituted derivatives of barbituric acid (vary by R group from carbon to alkyl, saturation, bromo groups, phenyl group)

Not highly potent methaquolene

Other depressantsSedatives HypnoticsCertain barbiturates

Soothing of distress without effects of sleep i

tranquilizers are milder than sedatives

Class of drugs that produce sleep

Ex: Chloral hydrateEx: Phenobarbital

(barbiturate) behaves as either a sedative or hypnotic dependent upon dose

Continuum of Sedation Behavior

DeathComaGeneral AnesthesiaHypnosisSedationDisinhibitionRelief of AnxietyNormal

Increasing Dose

Ethanol – a common depressantCapable of

hydrogen bonding, but also

Fat soluble (small size)

Readily penetrates cell and tissue membranes

Easily and completely absorbed from the entire gastrointestinal tract.

Ethanol – a common depressant30-50 mg / 100 mL

blood

100 mg / 100 mL blood

200 mg / 100 mL blood

400 mg / 100 mL blood

mild intoxication; Silly behavior

slurred speech; staggering; aggression

vision and movement difficult

Coma, death

Ethanol – a common depressant

Alcoholism – a diseaseProgressiveFrequently fatalMay run in families? genetic component

Other uses• Antiseptic

• Tincture of iodine

• mouthwashes

Discuss the social and physiological effect of the use and abuse of ethanol.

Include effects on the family, cost to society and the short-and long-term health effects.

Social Effects of the Abuse of Ethanol

Major social costs due to alcohol use and abuse.

In the U.S., Australia, Europe, Japan, and other countries, over 80% of all alcohol-induced costs are borne by society.

Connected to many different degrees of crime.

MADD

Physiological Effects of EthanolShort-term effects:

DepressantImpairs CNS function proportional to intake of

alcoholImpacts Pregnancy - Miscarriage, low birth

mass and fetal abnormalities.

Long-term effects:Cirrhosis and cancer of the livercoronary heart diseasehigh blood pressureStrokesDigestive issues - gastritis, peptic ulcers.Poor eating habits.

Other Physical EffectsDriving

impairmentAlcoholism is a

diseaseIncludes

physical and psychological addiction as well as genetic factors

Enhances the effects of other drugs.

Describe the synergistic effect of ethanol with other drugs.

Reactions with other Drugs

Synergistic Effects - combination of two drugs is more harmful than either drug taken aloneAlcohol + aspiring – increase risk of stomach

bleedingAlcohol + sedatives - increases risk of heavy

sedation leading to coma and deathAlcohol + cocaine – cocaethylene forms…

extends high… but is very toxic… causes severe constriction of blood vessels (high blood pressure)… and irregular heart beat.

Alcohol + bezodiapenes (mogadon, valium) – suppresses CNS leading to death

Describe and explain the techniques used for the detection of ethanol in the breath and in the blood or urine.

Include potassium dichromate (VI) in the breathalyzeranalysis of blood or urine by chromatographyabsorption of infra-red radiation in intoximeter.

Detecting BAC (Question 12)Breathalyzer test

(potassium dichromate [K2Cr2O7] used as oxidizing agent).

Gas Liquid Chromatography

Takes breath sample and detects presence of gases at a quantitative level.

Blood and urine can be used in the machine as well.

Detecting BAC (continued)Infra-Red Spectroscopy (“intoximeter”)IR absorption at 2950 cm-1 is used to detect

presence of the C-H group.Very accurate (% C-H absorbed acts as a

marker for BAC).

Other Commonly Used DepressantsNitrazepam (mogadon)Hypnotic, induces sleep, control seizures and infantile spasms

Prozac (Fluoxetine hydrochloride)Anti-depressant used for mental depression, increases activity of the neurotransmitter serotonin

Depressants are often described as anti-depressants because they relieve depression

Valium (diazepam)relief of anxiety and tension

Carbon skeleton structures of diazepam and nitrazepam are the same, the two differing in side groups.The structure of Prozac differs from the other two