Psyc 222 1st Edition Lecture 7 Outline of Last Lecture i. Resting membrane Potentialii. How is the resting membrane potential generated?iii. How do Drugs fit into this pic?Outline of Current Lecture The Actions of Drugs i. Sources of drugsii. Categories of drugsiii. Drug identificationiv. Types of drug effectsv. Estimating time safety marginvi. Time dependent factorsCurrent LectureI. Many drugs are chemically derived from plants. Why do plants produce so many psychoactive drugs? Where do the nams of drugs come from? Chemical name is a complete description of the molecule. (Ex: 2-[9diphenylmethyl)sulfinyl]acetamide) Generic name is the official name (legal), listed in the U.S pharmacopoeia. (Ex: Modafinil) Brand name is the specific drug or formulation trademarked by manufacturer, can be patented for 20 years. (EX: Provigil)II. Stimulants produce wakefulness, or a sense of energy. Depressants slow the nervous system activity. Opioids (narcotics) reduce pain. Hallucinogens give a sense of altered perceptions. Psychotherapeutics treat symptoms of mental disorders. (Marijuana and Nicotine belong in several categories.III. Importance of identification: So physicians can tell from appearance the exact drug and dose. ("Physicians Desk Reference" includes photographs of pharmaceuticals). Illegal drugs are sometimes shaped, marked, or packaged in an identifiable way. (EX: MDMA "ecstasy"). Drugscan als be tested and identified through chemical analysis. A single drug has several official names. Pharmaceutical companies give promising new drugs a code name, such as SCH22390. Its chemical name provides a complete description of a particular molecule according to th rulesof organic chemistry.IV. Non-specific derive from users unique background, expectations, perceptions, and enviornment. Placebo effects are nonspecific. Placebo effects are produced by an inactive chemical that the user believes to be a drug. This is important in treating pain and major depression. Specific effects depend on the prescence of a chemical at certain concetrations.V. Safety margin is the difference between a dose that produces a desired therapeutic effect in most patients and the lowest dose that produces an unacceptable toxic reaction. Potenaj is the amount of drug required to produce a given effect. Side effects are the unintended efects that accompany therapeutic differences. Effective dose is a dose that producesan effect in some percentage of tests subjects. (ED50 is the effective dose for half the animals in a drug test). Lethal dose is a dose that has lethal effects in some percentage of test subjects. (LD50 is the lethal dose for half the animals in a drug test). Therapeutic Index= LD50/ED50, always greater than 1, most drugs have a LD, well above the ED95.VI. The time course of drugs depends on:1. how the drug is administered2. how rapidly it is absorbed 3. how it is eliminatedDrug effects can be prolonged by taking additional doses at specific time intervals. Intervals varybetween drugs. Taking multiple doses too close together will increase the maximum blood level of the drug, possbly leading to cumulative
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