D.4.1 Describe the effects of
depressants.
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?
0 Low Doses:
0 Little, or no effect.
0 Moderate Doses:
0 Feeling of calm, relieve anxiety.
0 Large Doses:
0 Induce sleep.
0 Extremely high Doses:
0 Death.
D.4.2 Discuss the Social and
Physiological effects of the use and
abuse of ethanol.
Alcohol?
0 In Medicine:
0 Alcohol used as antiseptic before injections and to
harden skin.
0 Drinking:
0 Psychological and physical dependence; alcoholism.
0 Huge 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.
0 Heavy Drinking:
0 Severe liver disease.
0 Cirrhosis, 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.
0 Sudden discontinuation by heavy users can cause
delirium tremens (the ‘DTs’).
0 Severe shaking, can last up to four days.
D.4.3 Describe and explain the techniques
used for the detection of ethanol in the
breath, the blood and urine.
Breathalyzer &
Chromatography
0 Breathalyzer:
0 Acidified potassium or sodium dichromate(VI) crystals
turn green as they are reduced by alcohol to Cr3+.
0 Chromatography:
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.4.4 Describe the synergistic effects
of ethanol with other drugs.
0 Alcohol enhances the effect of other drugs because it
depresses the CNS (Synergistic effect)
0 Fatal.
0 Alcohol taken with Aspirin increases the risk of
stomach bleeding
D.4.5 Identify other commonly used
depressants and describe their structures.
Other Depressants
0 Commonly prescribed to:
0 Reduce anxiety, relieve stress, help insomnia.
0 These include the benzodiazepines and Prozac.
0 Usually only prescribed for limited period while
counselling or psychotherapy are used, as these an
induce dependence.
0 Also used as a premedication in hospitals before
general surgery.
D.4.5 Identify other commonly used
depressants and describe their structures.
Structures.
Diazepam (Valium)
Nitrazapam (Mogadon)
Fluoxetine
hydrochloride
(Prozac)