1. Medicines and drugs Depressants

2. depressants depress the central nervous system; they calm and relax the nervous system as they slow down the action of the brain, heart and other organs.

3. Effects of depressants doseeffect lowmay exert little or no effect. moderatemay induce sedation, soothing, reduction of anxiety, impaired judgement highmay induce sleep, unconsciousness, slurred speech, altered perception extremely highmay cause organ failure, coma or death

4. Social effect of ethanol use/abuse increased risk when driving or operating machinery involvement in violence or crime relationship problems taking time off work as a result of sickness or death associated with alcohol abuse loss of income hospital costs lower economical production

5. Short term physiological effects reduces tension, anxiety and inhibitions impairs function of central nervous system

6. Long term physiological effects liver damage/cancer cirrhosis increased blood pressure heart disease or stroke miscarriage and fetal abnormalities tolerance and physical dependence

7. Synergetic effect of ethanol with other drugs Ethanol produces a synergic effect with other drugs i.e. their effect is enhanced in the presence of alcohol which can be dangerous e.g. with aspirin it can increase damage to stomach and cause bleeding. In the case of sleeping tablets and other sedatives it can cause coma or death.

8. D.4.4 Describe the synergistic effects of ethanol with other drugs. Synergistic effect : When the combination of two drugs is more harmful than either drug taken alone. Heath Ledger is thought to have died because of the synergistic effect of mixing prescription drugs. The six drugs he took were medically safe, but mixed together the result was deadly. Alcohol taken with aspirin increases stomach bleeding When alcohol is taken with cocaine, cocaethylene is formed, which is far more toxic than either used separately. Alcohol can also be fatal when taken with benzodiapenes (hypnotics) such as valium.

9. Using potassium dichromate Only used for detection in breath - breathalyzer. In a positive result (i.e. presence of alcohol) the potassium dichromate changes form orange to green when ethanol is present as the potassium dichromate is reduced and the ethanol oxidized to ethanoic acid. Equations oxidation: C 2 H 5 OH + H 2 O → CH 3 COOH + 4H + + 4e − reduction: Cr 2 O 7 2 − + 14H + +6e − → 2Cr 3+ + 7H 2 O

10. D.4.3 Describe and explain the techniques used for detection of ethanol in the breath, the blood and urine. Blood Alcohol Concentration (BAC) is grams of ethanol per 100cm 3 of blood. Some countries will have a legal limit on the BAC for driving a car. In the U.S. it is often 0.08% (80mg per 100cm 3 of blood). Ethanol is volatile, so when the blood stream passes through the lungs, an equilibrium is established and you essentially breathe out ethanol vapours.

11. D.4.3 Describe and explain the techniques used for detection of ethanol in the breath, the blood and urine. Road breathalyzers would use acidified potassium dichromate (K 2 Cr 2 O 7 ). Recall that potassium dichromate is orange in color. The alcohol acts as a reducing agent and reduces the Cr 6+ to Cr 3+, which turns the color green. However, these tests could not be held up in a court of law, so more accurate analysis needs to be performed using gas liquid chromatography or infra-red spectroscopy.

12. intoximeter Used for breath, blood and urine. Infrared radiation is passed through breath, blood or urine. The C–H bond in ethanol causes radiation to be absorbed at a specific wavenumber which is 2950 cm -1. The intoximeter measures the amount of absorption which depends upon the amount of ethanol in the breath i.e. the more ethanol there is present the more IR is absorbed. The amount or peak is compared against a standard (e.g. allowed amount).

13. D.4.3 Describe and explain the techniques used for detection of ethanol in the breath, the blood and urine. Modern intoximeters can use infra-red spectroscopy to determine BAC. Infra-red energy is sufficient to cause vibrational motions. The amount of motion depends on the mass of the atoms and the length/strength of the covalent bonds. Since water vapor is in the breath, the O-H peak cannot be evaluated. However, the C-H peak can be evaluated. This is why this intoximeter would not be able to tell the difference between propanone and ethanol.

15. gas-liquid chromatography Used for blood and urine samples. Ethanol is separated from the urine or blood using gas-liquid chromatography Accurate as area underneath ‘ethanol’ peak in chromatogram indicates amount of ethanol in blood or urine.

16. D.4.3 Describe and explain the techniques used for detection of ethanol in the breath, the blood and urine. In gas liquid chromatography, a breath, blood or urine sample is obtained. A carrier gas such as N2 is used, and this moves through a column carrying a non-volatile liquid. Different components of the blood or urine are separated based on boiling point and detected. Unlike the infra-red spectroscopy, this can tell the difference between ehtanol and propanone found in the breath of diabetics.

17. Other commonly used depressants depressantstructure: functional groups Fluoxetine hydrochloride (Prozac®) aromatic benzene, ether, secondary amine, fluorine, chloride ion diazepam/Valium®;  amide/ketone/carbonyl;  (tertiary) amine; nitrazepam/Mogad on®;  amide/ketone/carbonyl;  (tertiary) amine;

18. D.4.5 Identify other commonly used depressants and describe their structures. Valium (diazepam): Sedative drug. Most prescribed drug in the world and used to relieve anxiety and tension. Mogadon (nitrazepam): Common sleeping pill. Also used to control seizures. Prozac (fluoxetine): Anti-depressant drug. Used to treat mental depression. Increases activity of serotonin.