DEPRESSANTS

Depressants

Tranquilizers, sedatives, hypnotics.

Relax the CNS.Interfere with nerve

impulse transmission.Slow down activity of

brain, heart.Reduce breathing rate

and emotional response.At high doses – Sleep Extremely high doses -

Death

Tranquilizers

Alcohol, valium (diazepam), librium.

Reduce nervous tension, anxiety.

Sedatives

eg. Barbituarates (a class of drugs that are depressants)

Soothing of distress.Without sleep.Tranquilizers are

milder than sedatives.

Hypnotics

Produce sleep.Chloral hydrate.Phenobarbitol.

Increasing the dose of depressants

NormalRelief of anxietyDisinhibitionSedationHypnosis (sleep)General anaestheticComaDEATH

Ethanol

Fat solublePenetrates cell, tissues

membranesEasily absorbedMild intoxication (euphoria)Silly behaviourNeurological problems

(slurred speach, staggering)

Aggressive behaviourComaDeathAlcoholism

Alcohol-Other uses

AntisepticMouthwash

Effects of alcohol

Social Physiological

Please take notes using page 416.

Short termLong termSynergistic (when

combination is more harmful than either drug)

Please take notes from pages 416, 417.

Blood Alcohol Concentration (BAC)

Mass in grams of alcohol per 100 cubic centimetres of blood.

Sometimes listed as a percentage.

Alcohol in blood in equilibrium with alcohol vapour in lungs

Therefore a breathalyser test can be used

Breathalyser Test

A redox reactionPotassium

dichromate is oxidising agent.

Oxidises alcohol to ethanoic acid.

Orange Cr(VI) to green Cr (III).

Transfer of electrons produces emf.

Gas Liquid Chromatography

Components move through column at different speeds.

Detected and analysed.See page 418 for notes.

Infra-Red Spectroscopy

IR energy vibrates moleculesEach molecule absorbs different range of

radiation.Eg OH bond is at characteristic

wavelength.See page 418 for notes.

Valium

Worlds most prescribed drug

SedativeRelieves anxiety,

tensionInhibits nerve

transmission by interacting with inhibitors

Nitrazepam (mogadon)

Common sleeping pill

Also used to control seizures and infantile spasms

Phenyl group, fused benzene ring, with a 7 membered heterocyclic ring, secondary amine

Compare to valium

Prozac

Anti-depressantIncreases activity of

seratonin (a neurotransmitter)

Contains amine group

Questions

7, 8 and 9 on page 435.