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https://www.healthtap.com/#topics/the-depressant-effects-of-alcohol http://rhinepharmaceuticals.com/innovation-and-development/ Medicines and Drugs 4 Depressants (SL and HL) 1 The Drug Development Process D.4.1 Describe the effects of depressants. Distinguish between effects at low, moderate and high doses. D.4.2 Discuss the social and physiological effects of the use and abuse of ethanol. D.4.3 Describe and explain the techniques used for the detection of ethanol in the breath, the blood and urine. Include the breathalyzer, chromotagraphic tests of blood or urine, and the intoximeter. D.4.4 Describe the synergistic effects of ethanol with other drugs. D.4.5 Identify other commonly used depressants and describe their structures. Only diazepam (Valium), nitrazepam (Mogadon) and fluoxetine hydrochloride (Prozac) are required. 2 Common Depressant Drugs 3 Mode of Action of Depressants Depressants act on the central nervous system. i.e. brain + spinal cord Depressants “depress” or slow down brain activity. tranquilizers sedative hypnotic Slowing down brain activity may also affect other organs. muscle action respiratory function 4 Mode of Action of Depressants utube.com/ ugPM83c Signals pass from neuron to neuron in the brain. http://www.youtube.com/watch?v=90cj4NX87Yk Depressants often block receptors on neurons, preventing the normal binding of neurotransmitters. Transmission of signals from neuron to neuron stops. X X X Effect depends on the brain pathway. 5 Dose Dependent Effect of Depressants very high dose coma / death high dose hypnotic respiratory depression sleep inducing slurred speech staggered gait moderate dose sedative low dose tranquilizer greater soothing and relief of anxiety mild relief of anxiety muscle relaxant 6 Ethanol C2H5OH the “alcohol” in beer, wine, hard liquor produced through the fermentation of various crops polar molecule (due to OH group) small molecule → able to pass through cell membranes 7 Ethanol - Physiological Effects (Short Term) low dose sense of well being loss of inhibitions depressant action on brain centres related to tension and anxiety impaired concentration memory loss high dose staggered gait impaired motor function risk taking behaviour very high dose coma / death depressant action on brain centres related to co-ordination, balance, pain sensation, judgement depressant action on brain centres related to respiratory control 8 Ethanol - Physiological Effects (Long Term) cardiovascular disease brain damage strokes cirrhosis long term effects dependence high blood pressure stomach cancer fetal alcohol syndrome 9 Ethanol - Social Effects use abuse celebrations and ceremonies alcoholism loss of productivity motor vehicle accidents illness → health care costs others → 10 Ethanol - Synergistic Effects 1+1>2 synergy = combination of two drugs taken at the same time is more powerful than either drug taken alone (usually considered with respect to the negative side effects) alcohol + aspirin → increased stomach bleeding + ulcers alcohol + other depressants → heavy sedation possibly coma 11 Methods Used to Measure Ethanol Blood Alcohol Concentration (BAC) BAC = mass of ethanol in grams per 100 mL of solution legal limits = 0.08 g in 100 mL What mass of ethanol is present in a 50 cm3 blood sample with a BAC of 0.11? 0.11 g 3 mass ethanol = x 50 cm 3 100 cm = 0.055 g 12 Methods Used to Measure Ethanol 1. The Breathalyser Test portable device for roadside testing → measures alcohol vapour in breath chemical reaction = oxidation of alcohol by potassium dichromate ethanol + acidified dichromate → ethanoic acid + chromium (III) C2H5OH + H2O → CH3COOH + 4 H+ 4 e– x3 Cr2O72– + 14 H+ + 6 e– → 2 Cr3+ + 7 H2O x2 3 C2H5OH + 2 Cr2O72– + 16H+ → 3 CH3COOH + 11H2O 13 Methods Used to Measure Ethanol 1.The Breathalyser Test redox reaction → generates a small voltage → converted to a BAC reading often inaccurate and unreliable results not admissible in court disposable single use tests Cr2O72– Cr3+ 14 Methods Used to Measure Ethanol 2. The Intoximeter measures alcohol level in breath → more reliable → confirms roadside test results based on infra-red spectroscopy → molecules absorb IR radiation → molecules start to vibrate → bonds stretch → different bonds absorb different wavelengths of IR radiation 15 Methods Used to Measure Ethanol 2. The Intoximeter C-H bonds in ethanol can be analyzed on this profile to determine ethanol conc’n O-H bonds not used in the analysis (O-H bonds also present in water vapour) IR spectrum profile = type of substance peak heights = concentration 16 Methods Used to Measure Ethanol 3. Gas Liquid Chromatography can analyse alcohol levels in breath, blood and urine (separates molecules based on mass and solubility in column matrix) retention time area under peaks = concentration 17 Other Depressants benzodiazepams suppress brain activity in regions that control emotion used as tranquilizers, anti-anxiety drugs and sleep inducers diazepam similarities: 2 benzene rings nitrazepam heterocyclic ring amide (diazepine) differences: halogen vs nitro group 3º amide vs 2º amide properties: nonpolar ∴ ... 18 Other Depressants SSRI Inhibitors SSRI = selective serotonin reuptake inhibitor serotonin → neurotransmitter used in brain pathways for “well-being” → low levels associated with depression → SSRI keep serotonin levels high http://www.youtube.com/watch?v=sc-4zhqViQ4 SSRI ≠ not truly a depressant → does not depress CNS activity Prozac - antidepressant 19