D.4+Depressants

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= = **D.4 Depressants **


**Describe the effect of depressants** 

[|Depressants] are drugs prescribed by a doctor that affect the central nervous system, (brain and spinal cord), by changing the concentration of neurotransmitters causing a decrease in brain activity and breathing rate. They dull emotional responses. There effect is to produce a soothing / calming effect to reduce anxiety and help people sleep. (Brown & Ford 345). Examples: sleeping pills, tranquilizers, and sedatives.

  
 * Side effects:**
 * __Low doses__ - increase feeling of calm, drowsiness, relief of anxiety/tension, reduction of inhibition, slower mental activity
 * __Moderate to higher doses__ - slurred speech, faltering movement, altered perception, and sleep.
 * __High doses__ - decreases breathing and heart rates, sleep, loss of consciousness, coma, and death.
 * Types of depressants: **
 * barbiturates - prescribed by a doctor
 * benzodiazepines - prescribed by a doctor
 * <span style="font-family: Verdana,Geneva,sans-serif;">Self medicating depressants - alcohol (beer, wine, etc.) and narcotics (heroin, marijuana, etc.).
 * Antidepressants** are drugs used to treat severe depression in people suffering from clinical depression. They are prescribed by a psychiatrist. NOTE: Depressants are often described as antidepressants because they relieve depression (IBO).

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<span style="font-family: Verdana,Geneva,sans-serif;"><span style="color: rgb(0, 0, 255); font-size: 110%;">**Discuss the social and physiological effects of the use and abuse of ethanol.** Ethanol, the depressant found in alcoholic beverages, is the most common of the legal depressants. Abuse of ethanol has a large number of short-term and long term effects, as this table illustrates:

"In summary, chronic consumption of large amounts of ethanol is a major source of social and physiological problem. It has been said that if ethanol were to be discovered today it would probably not pass the regime of drug testing and would be a restricted drug."

The dependence to alcohol is widespread, to the extent that it represents 3.5% of the total number of disease cases worldwide (Encarta), and several volunteer organizations such as [|Alcoholics Anonymous] exist to assist people with their addiction to alcohol.

On a social level, alcoholism can cause numerous issues, such as increased aggressiveness and hostility while intoxicated. On a long term level, dependence on alcohol eventually results in the inability to control alcohol consumption. This can result in a deterioration of relationships, and a general decrease in performance in daily activities. This can result in decreased school and work performance, and is frequently accompanied by job loss. Alcoholism affects the surrounding community of an individual, as well as the mental health of the individual.

Historically speaking, alcoholics have been viewed as irresponsible, immoral, of weak character and generally responsible for their actions. While dependence to alcohol itself has been increasingly recognized as a legitimate disease in the scientific and medical community, the public's views concerning alcoholism remain ambivalent.

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<span style="font-family: Verdana,Geneva,sans-serif;"> **<span style="color: rgb(0, 0, 255);">Describe and explain the techniques used for the detection of ethanol in the breath, the blood and urine. **

The damaging effects that an individual's alcohol intake can have others has caused most countries to institute processes to test for the presence of ethanol in the body. This is linked to legislation that sets limits for body ethanol concentration for the performance of certain activities. An upper limit of 80 mg ethanol per 100 cm3 of blood is set for driving any vehicle in most countries. Analysis of ethanol concentration generally is set on samples of the breath, blood, or urine. More recently, techniques have been developed in which ethanol concentration may be possible to detect in saliva or eye fluids.

Ethanol establishes an equilibrium between being dissolved in the blood and being in exhaled breath. C2H5OH(aq) in blood <--> C2H5OH(g) The equilibrium constant, Kc for this reaction does not change with temperature so if you measure the concentration of ethanol in the breath you can determine the concentration in the blood.



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 * Roadside breathalyzer (breath)**
 * <span style="font-family: Verdana,Geneva,sans-serif;">For analyzing alcohol in breath
 * <span style="font-family: Verdana,Geneva,sans-serif;">The person blows into a photocell device containing orange potassium dichromate(VI) crystals (K2Cr2O7) which are reduced to green chromium (III) ions if ethanol is present. (see topic 10.4)
 * <span style="font-family: Verdana,Geneva,sans-serif;">The ethanol is reduced to ethanoic acid.
 * <span style="font-family: Verdana,Geneva,sans-serif;">The larger the concentration of ethanol present, the more the potassium dichromate (VI) is reduced and the greener the crystals become.
 * <span style="font-family: Verdana,Geneva,sans-serif;">The photocell determines the change in concentration of ethanol by measuring the degree to which the color changes.
 * <span style="font-family: Verdana,Geneva,sans-serif;">Not accurate to be used in court to convict someone.

More accurate than roadside breathalyzer. Used to measure alcohol in the breath Found at the police station. Uses [|infrared (IR) spectroscopy].
 * Intoximeter (breath)**

__How does it work__ (the simple version) <span style="font-family: Verdana,Geneva,sans-serif;"> __How does it work__ (more details) The atoms in a molecule are constantly moving due to the fact that the bond angles and lengths between them are constantly changing due to the fact that the bond vibrate (stretching, bending). The bond vibrations produce an electric field with the same wavelength as that of IR radiation. Since each molecule has a unique set of bonds, each molecule will produce its own IR spectrum (a fingerprint).
 * <span style="font-family: Verdana,Geneva,sans-serif;">The person breathes into the infrared spectrometer.
 * <span style="font-family: Verdana,Geneva,sans-serif;">Absorption of infrared (IR) radiation of a specific wavelength by the -O-H bond in the ethanol produces a characteristic peak on the spectrum.The amount of absorption depends on the concentration of ethanol in the breath
 * <span style="font-family: Verdana,Geneva,sans-serif;">Ethanol is compared with air or a reference sample to determine if it is over the allowed amount

The homologous series of alcohols produce a characteristic IR spectrum due to the fact they each have a hydroxyl functional group (-C-O-H) that is unique to them. They all have a O-H and the C-O stretching vibrations which appears in the region 3500-3200 cm-1 as a very intense, broad band. The C–O stretch shows up in the region 1260-1050 cm-1. The size of the peak can converted into an ethanol concentration.



Can only be done in a laboratory. Gives very accurate results. Blood or urine is vaporized and injected into a stream of an inert gas over the surface of a non-volatile liquid. Due to their different suitabilities and and boiling points the molecules in the blood or urine travel as different speeds along the liquid. The time taken to move along the liquid is called the retention time.
 * Gas-Liquid Chromatography (blood and urine)**

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<span style="font-family: Verdana,Geneva,sans-serif;"> **<span style="color: rgb(0, 0, 255);">Describe the synergistic effects of ethanol with other drugs **

Ethanol can interact with and increase the activity of other drugs when taken at the same time, as it depresses the central nervous system itself. This is known as **synergy**. It means that alcoholic drinks should not be consumed when taking other medications. One of the problems is that because ethanol is such a widely consumed and socially available drug, many people do not consider its interaction with other prescription and non-prescription drugs.

Some examples of **synergistic effects** include, and are not limited to: <span style="font-family: Verdana,Geneva,sans-serif;">
 * <span style="font-family: Verdana,Geneva,sans-serif;">Aspirin with alcohol can cause increased bleeding in the stomach lining
 * <span style="font-family: Verdana,Geneva,sans-serif;">Alcohol with other depressants such as barbiturate, including sleeping pills, ethanol can induce heavy sedation possibly leading to a coma
 * <span style="font-family: Verdana,Geneva,sans-serif;">Alcohol with tobacco can increase the incidence of cancers, notably in the intestines and the liver
 * <span style="font-family: Verdana,Geneva,sans-serif;">Alcohol along with drugs can interfere with the metabolism by the liver, which can cause greater and more prolonged drug effects.

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<span style="font-family: Verdana,Geneva,sans-serif;"><span style="color: rgb(0, 0, 255); font-size: 110%;">**Identify other commonly used depressants and describe their structure**


 * 1. Benzodiazepines** - Seven-member ring fused to an benzene ring with four main substitute groups

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 * a) Diazepam (valium)**
 * <span style="font-family: Verdana,Geneva,sans-serif;">Seven-member ring containing two N atoms fused to an benzene ring.
 * <span style="font-family: Verdana,Geneva,sans-serif;">One of the carbon atoms on the benzene ring has a chloro (-Cl) functional group attached to it.
 * <span style="font-family: Verdana,Geneva,sans-serif;">On the 7 member nitrogen containing ring one carbon atom is attached to a methyl (CH3) group, one a carbonyl (C=O) functional group and one a bezene ring.
 * b) Nitrazepam** (sleeping pills)
 * <span style="font-family: Verdana,Geneva,sans-serif;">Seven member ring fused to an benzene ring.
 * <span style="font-family: Verdana,Geneva,sans-serif;">One of the carbon atoms on the bezene ring has a nitro group NO2 group attached to it.
 * <span style="font-family: Verdana,Geneva,sans-serif;">On the 7 member nitrogen containing ring is a carbonyl (C=O) functional group.
 * <span style="font-family: Verdana,Geneva,sans-serif;">On the 7 member nitrogen containing ring one carbon atom is attached to a carbonyl (C=O) functional group and one a benzene ring.

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 * 2. Prozac (Fluoxetine Hydrochloride**)
 * <span style="font-family: Verdana,Geneva,sans-serif;">two benzene ring, one with a carbontrifluoride (CF3) group attached to it.
 * <span style="font-family: Verdana,Geneva,sans-serif;">Joined by an ether group (C-O-C) and a carbontriflouride (CF3) and secondary amine (-N- ).

Sources Cited: -"Alcoholism," Microsoft® Encarta® Online Encyclopedia 2009 <span style="font-family: Verdana,Geneva,sans-serif;">-Bro wn, Catra and Mike Ford. __Standard Level Chemistry.__ Heinemann Baccalaureate, 2008. -<span style="font-family: Arial,Helvetica,sans-serif;">Derry, Lanna, Maria Connor and Carol Jordan. __Chemistry for use for the IB Diploma Standard level.__ Melbourne: Pearson Education, 2008. - IB Chemistry Data Booklet