7850555
Description
Flashcards by Margaret-Estefani Conde Paredes, updated more than 1 year ago
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Created by Margaret-Estefani Conde Paredes
almost 8 years ago
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| Question | Answer |
| What is DRUG DEPENDENCE? | a state, psychological and/or physical, resulting from an interaction between a drug and an organism characterized by a compulsion to take the drug on a continuous or periodic basis to experience its psychic effects and/or avoid the discomfort of its absence |
| What is the difference between psychological and physical dependence? | psychological dependence is the need or desire to take the drug again whereas physical dependence causes physiological changes in the body and it is most common with depressant drugs |
| Drug dependence is classified on the basis of the dependence producing compound. Name the 6 major groups | 1. depressants: alcohol, barbiturates 2. Opiates: heroin, morphine 3. stimulants: amphetamines, cocaine, ecstasy 4. hallucinogens: LSD, magic mushrooms 5. inhalants: glue, solvents 6. cannabis: classes alone |
| Production of dependence | *Acute administration of a drug of abuse will produce acute effects related to that drug. * The psychological effects must somehow reinforce the administration of the drug *On repeated use tolerance may develop leading to an increase in the dose of drug required to produce the required effect. |
| Psychological dependence occurs and is defined as | : ‘a condition in which a drug produces a feeling of satisfaction and a psychic drive that requires administration of the drug to produce pleasure or avoid discomfort. Psychological dependence varies from mild to strong depending on the drug used. |
| Physical dependence is | ‘an adaptive state that manifests itself by intense physical disturbance when the drug is discontinued’. *Physical dependence is not produced by all drugs of abuse and is most pronounced after use of depressant drugs such as alcohol or heroin.* If a drug usage is halted withdrawal or abstinence occurs, the symptoms of which can be psychological (i.e. cravings, discomfort etc) and/or physical on the basis of whether physical and psychological dependence are present. To avoid withdrawal symptoms drug administration is continued and a cycle is set up. |
| What is the basis for psychological dependence? | **The psychological effects of drugs are understood to involve dopamine systems in the CNS that mediate reward and reinforcement and reside in the ventral tegmental area of the midbrain and run up to the cortex. All recreational drugs act on this system in some way as do external stimuli that we find pleasureable** |
| What is the basis for physical dependence? | The production of dependence (physical) by the depressant drugs is thought to result from an adaptation of the CNS to the altered environment due to chronic drug use. Depressant drugs in the CNS is believed to establish a new homeostatic state by supersensitivity of the pathways involved, counteracting the drug depression. When the drug is discontinued the depressive effect is removed and dramatic withdrawal symptoms result from this supersensitivity. Since opiates act on specific opiate receptors the withdrawal symptoms are relatively specific whereas withdrawal from a general depressant such as alcohol produces more marked and generalized symptoms. |
| What does ''supersensitivity'' results from? | 1. receptor supersensitivity 2. unmasking of other neuronal pathways 3. enzyme induction 4. nucleotide changes or coupling to receptor 5. membrane depolarization |
| What are the treatments for supersesitivity? | 1. aversion and other behavioural treatments 2. substitution drug therapy 3. clinics, residential homes, etc. |
| What are the majore problems of drug dependence and abuse? | 1. overdose 2. crime as a result of need to obtain drug 3. withdrawal symptoms- may be life threatening 4. retreat from society 5. acute effects of a particular drug and the chronic pathological effects 6. AIDS, hepatitis etc. as a result of injection. Injection of tablets 7. Drug combinations |
| Legal issues. | There are 3 classes of drugs (A, B and C) and penalties for possession and trafficking very based on the class- you are no doubt aware of the downgrading of cannabis from class B to C. |
| Can you name depressants and their main characteristics? | - alcohol, heroin, methadone and solvents - alcohol: relaxation, disinhibition in social settings, slow reactions - heroin (acts on the mu receptor for endogenous opioids and causes a feeling of well being , being wrapped in cotton wool) - problem: unknown purity of the drug, an overdose is common and the vomiting, respiratory depression and sedation can be a fatal mix. -heroine and morphine in their pure controlled forms are safely used by millions of patients in pain who do not become dependent |
| What are the main stimulants and their mechanims? | -amphetamines, ecstasy, cocaine, tobacco and caffeine -increase heart rate, sense of alertness and energy. (may become agressive) -cocaine elevates mood by a block of reuptake of NA ... crack is the faster version - amphetamines increase the levels of NA and DA -ecstasy has additional effetcs on 5HT |
| Can you name three types of stimulants and their mechanisms? | -cannabis, LSD, magi mushrooms - they change the way people think, feel and perceive their surroundings, enhance appreciation, can cause anxiety or paranoia. -don't cause physical dependence but a user may become psychologically dependent on their effects. - LSD acts on 5HT systems and is likely to interfere with the way the brain processes sensory information. -cannabis acts on a CB1 receptor in the brain to cause muscle relaxation, changes in short term memory, mild increases in mood and analgesia |
| Pharmacology of alcohol | general depressant of most neural systems, Ca2+ channels |
| Pharmacology of Barbiturates | depressants by increasing Cl- channel open time |
| Pharmacology of opiates | decrease release of other neurotransmitters (NA, DA, 5HT, ACh, etc) and direct hyperpolarization of cells |
| Pharmacology of cocaine | blocks reuptake of NA (and DA) |
| Pharmacology of amphetamine | releases NA and DA, blocks DA reuptake. Ecstasy also has a weak LSD-like actions and releases 5HT as well as DA |
| Pharmacology of LSD | inhibits activity of 5HT neurones |
| Pharmacology of cannabis | -inhibitory receptor-CB1 |
| Pharmacology of glue and solvents | general depression, hypoxia |
| Pharmacology of nicotine | central and peripheral receptor mechanisms |
| What are the type drugs that cause physical withdrawal? | only depressant drugs (opiods, alcohol) |
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