Depressants

1. Depressants

2. Depressants • Depress the central nervous system by interfering with the transmission of neural impulses in the nerve cells (neurons)

3. Effects of Depressants • Slow down bodily functions especially motor activity and mental activity • Low doses • Feelings of calm and reduced anxiety • Induced sleep • Large doses • Loss of consciousness, coma, death

4. Alcohol • Ethanol is the only common alcohol that can be consumed. Other common alcohols such as methanol and isopropyl are much too toxic. • Alcohols are used as antiseptics for injections and to harden skin

5. Alcoholism • Prolonged consumption of alcohol leads to both psychological and physiological dependence • Alcoholism also results in • Violent antisocial behavior • Social costs to families • Safety issues especially road accidents

6. Alcohol Consumption • Short term effects • Relaxation, confidence, and increased sociability • Dialation of blood vessels leads to feelings of warmth • Impaired judgment • Lengthened neural response time

7. Alcohol Consumption • Long term effects of heavy drinking • Cirrhosis of the liver and liver disease • Coronary heart disease • High blood pressure and strokes • Dementia • Miscarriage • Fetal abnormalities and fetal alcohol syndrome

8. Synergistic Effects of Alcohol • Ethanol can interact with other drugs, often enhancing their effect, because it inhibits the functioning of the central nervous system • The synergistic effect can be fatal when alcohol is taken with certain drugs including • Benzodiazepines • Narcotics • Barbituates • When taken with aspirin it increases the likelihood of stomach bleeding

9. Alcohol Withdrawal • Sudden discontinuation of alcohol by heavy drinkers leads to withdrawal symptoms including • Delirium • Tremors’

10. Legal limits for driving • All states in the US and many countries have established 0.08% blood alcohol as the legal limit for driving. • After drinking the concentration of alcohol in the blood increases as the alcohol is absorbed and then gradually declines.

11. Legal limits for driving Estimates of the alcohol consumption needed to exceed the legal limit of 80 mg per 100 cm3 of blood for an average adult. 1 unit = 280 cm3 of beer = Glass of wine = Shot of liquor Values are based on an average adult male weighing 150 pounds. Unit values For women are somewhat less due to a lower body mass and lipid distribution

12. Alcohol detection Breathalyser tests • Reduction of potassium dichromate to Cr3+ ion • Fuel cell where alcohol is oxidized to produce an electric current • Infrared spectroscopy- intoximeter • Gas Chromatography

13. Chemical Breathalyzers • The dichromate ion, Cr2O72-, has an orange color while chromium (III) ion, Cr3+, is green. • By determining the level of green color present one can determine the ethanol concentration.. • The ethanol absorbed by the dichromate solution can be calibrated against blood alcohol levels • The reaction is somewhat time dependent, therefore it is necessary to compare colors rather than titrate the solution to an endpoint.

14. Chemical Breathalyzers Alcohol chemical breathalyzer tests employ a chemical colorimetric test to ascertain alcohol blood levels. This test is based on the fact that primary alcohols such as ethanol are oxidized by acidified potassium dichromate as follows 3 C2H5OH + 2 Cr2O72- + 16 H+ 3 CH3COOH + 4 Cr3+ + 11 H2O

15. Other Depressants • Certain medicines known as antidepressants are used to treat anxiety, stress, and clinical depression • These include • Diazepam (Valium) • Nitrazepam • Fluoxetine hydrochloride (Prozac)

16. Fluoxetine Hydrochloride (Prozac) • Prozac is an example of the selective serotonin reuptake inhibitor (SSRI) • SSRIs work by preventing neurons (nerve cells) from pulling in the serotonin that is floating in the space between neurons. This allows more serotonin to build up and improves communication between the neurons.

17. Tranquilizers • Tranquilzers depress the nervous system responses but do not address the underlying problems. • They are used to sedate people in the short term but can be very addictive • Valium • Xanex • Nitrazepam

18. Tranquilizers • Tranquilizers are often temporarily prescribed for people facing high stress or anxiety. • Valium • Xanax • These drugs are usually prescribed for brief time until counseling and psychotherapy can be put in place. • They are occasionally used as a pre-medication before surgery. • Prolonged and over use of tranquilizers results in drug dependence.

19. Xanex – A Common Tranquilizer • Xanex is a common tranquilizer prescribed for persons suffering from acute anxiety. Prolonged use can lead to addiction The Chemical structure of Xanex

20. Halcion • Halcion is a trade name for a type of compounds known as a benzodiazopine. It is similar in structure to other tranquilizers Halcion is a commonly prescribed sleeping medicine

21. Barbituates • Barbiturates are short acting, and include pentobarbital, secobarbital, and amobarbital. • Affect the cortex and create a state similar to alcoholic intoxication in large doses. • Extremely dangerous when mixed with alcohol or other drugs. • A person in withdrawal suffers anxiety, agitation, loss of appetite, nausea and vomiting, sweating, a fast heartbeat, tremors, and cramps. • These symptoms can escalate to convulsions, delirium, and hallucinations.

22. Some Barbituates • Barbiturates have been known since 1864 when Dr. A. von Bayer synthesized barbituric acid. • In 1903, barbital was introduced as a hypnotic for routine medicinal use. Barbituic Acid Sodium pentathol