Depressants (D.4)Ali Q, Sohrab R.

Depressants?

• Drugs which depress the CNS.• Interfere with transmission of nerve impulses in the

neurones. • Slow down bodily functions including mental activity.• Most commonly taken depressant is alcohol • (H3C-CH2-OH)

• Sometimes called anti-depressants.• Relieve symptoms of mental depression.

D.4.1 Describe the effects of depressants.

Effects?

0Low Doses:0 Little, or no effect.

0Moderate Doses:0 Feeling of calm, relieve anxiety.

0Large Doses:0 Induce sleep.

0Extremely high Doses:0 Death.

D.4.1 Describe the effects of depressants.

Alcohol?

0 In Medicine:0 Alcohol used as antiseptic before injections and to

harden skin.0Drinking:

0 Psychological and physical dependence; alcoholism.0Huge social costs due to:

0 Road accidents, violent behaviour , family breakdowns.

D.4.2 Discuss the Social and Physiological effects of the use and abuse of ethanol.

Short Term Effects.

0 Moderate quantities:0 Feeling of relaxation, confidence, increased sociability.0 Dilates small blood vessels.

0 Flushing and feeling of warmth.0 Judgement, concentration, progressively impaired.0 Violent behaviour.0 Slurred speech, loss of balance.

0 High quantities:0 Loss of consciousness.0 Risk of death from inhalation of vomit or stoppage of

breathing.

D.4.2 Discuss the Social and Physiological effects of the use and abuse of ethanol.

Long Term Effects.

0Heavy Drinking: 0 Severe liver disease.

0Cirrhosis, liver cancer.0 Linked with coronary heart disease, high blood

pressure, strokes, increasing risk of dementia.0 Can cause miscarriage and foetal abnormalities during

pregnancy.0Sudden discontinuation by heavy users can cause

delirium tremens (the ‘DTs’).0 Severe shaking, can last up to four days.

D.4.2 Discuss the Social and Physiological effects of the use and abuse of ethanol.

Breathalyzer & Chromatography

0Breathalyzer:0 Acidified potassium or sodium dichromate(VI) crystals

turn green as they are reduced by alcohol to Cr3+.

0Chromatography:0 Blood or urine sample using gas liquid chromatography

D.4.3 Describe and explain the techniques used for the detection of ethanol in the breath, the blood and urine.

0 Absorption of infrared radiation:0 C-H bonds in ethanol absorbs infrared radiation of a

particular wavelength

D.4.3 Describe and explain the techniques used for the detection of ethanol in the breath, the blood and urine.

0Alcohol enhances the effect of other drugs because it depresses the CNS (Synergistic effect)

0Fatal.0Alcohol taken with Aspirin increases the risk of

stomach bleeding

D.4.4 Describe the synergistic effects of ethanol with other drugs.

Other Depressants

0Commonly prescribed to:0 Reduce anxiety, relieve stress, help insomnia.

0These include the benzodiazepines and Prozac.0Usually only prescribed for limited period while

counselling or psychotherapy are used, as these an induce dependence.

0Also used as a premedication in hospitals before general surgery.

D.4.5 Identify other commonly used depressants and describe their structures.

Structures.

D.4.5 Identify other commonly used depressants and describe their structures.

Diazepam (Valium) Nitrazapam (Mogadon)

Fluoxetine hydrochloride (Prozac)