Medicines and drugsDepressants

depressantsdepress the

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

Effects of depressantsdose effect

low may exert little or no effect.

moderate may induce sedation, soothing, reduction of anxiety, impaired judgement

high may induce sleep, unconsciousness, slurred speech, altered perception

extremely high may cause organ failure, come or death

Social effect of ethanol use/abuse

increased risk when driving or operating machineryinvolvement in violence or crime relationship problemstaking time off work as a result of sickness or death associated with alcohol abuse loss of incomehospital costslower economical production

Short term physiological effects

reduces tension, anxiety and inhibitionsimpairs function of central nervous system

Long term physiological effects

liver damage/cancer cirrhosisincreased blood pressureheart disease or strokemiscarriage and fetal abnormalitiestolerance and physical dependence

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.

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: C2H5OH + H2O → CH3COOH + 4H+ + 4e−

reduction: Cr2O7 2− + 14H+ +6e− → 2Cr3+ + 7H2O

intoximeterUsed 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 wavelength which is 2950 cm. 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).

gas-liquid chromatography

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

Other commonly used depressants

depressant structure: functional groups

Fluoxetine hydrochloride (Prozac®)

• aromatic benzene, ether, secondary amine, fluorine, chloride ion

diazepam/Valium®; amide/ketone/carbonyl; (tertiary) amine;

nitrazepam/Mogadon®;

amide/ketone/carbonyl; (tertiary) amine;