PS268 Study Guide - Midterm Guide: Pharmacodynamics, Ataxia, Blood Proteins
Chap 5
Categries of drugs:
CNS stimulants: amphetamine, cocaine, nicotine, caffeine
CNS depressants: alcohol, barbiturates, sedatives, inhalants
Analgesics: pain relievers, morphine, heroin etc
Hallucinogens (psychadelics): LSD, ectasy, MDMA, PCP, weed
Psychotherapeutics
Duel Deficit Model of Psychostimulant Addiction:
-withdrawal from chronic stimulant use causes decreased availability of dopamine and serotonin, in
turn contributing to withdrawal and relapse
-dopamine dysfunction underlies anhedonia (inability to experience pleasure) and psychomotor
disturbances
-5-HT (serotonin) dysfunction causes depression, obsessive thoughts, lack of imoulse control
-stimulants and depressants do not counteract each other
-Narcotics are analgesics that produce relaxed, dream like state and can induce sleep
-antipsychotic drugs (thorazine, haldol) are called neurleptics which calm psychosis and help control
hallucinations
-lithium is used to control manic episodes
-nicotine and weed don't fit into classes properly
-nicotine is thought of as being mild stimulant but has relaxed properties of low dose depressant
-weed thought of as a relaxant, depressing drug but doesn't share other features of class and produces
altered perceptions at high doses
Commercially available drugs have 3 names: (1) brand name (2) generic (3) chemical
Pharmacodynamics: drug actions and drug effects
-placebo/nonspecific effects influenced by expectancy and experience (inactivty chemical that body
believes is a drug and releases GABA)
-specific effects are drug effects that depend on the presence of the chemical
Dose response relationships:
-a graph showing relationship b/w the dose and the effect is dose-responsive curve
-low dose = no effect, threshold = an effect is observed, highest dose = comatose
-at system's maximal response, further additions of drug have no effect and as it increases there are
slower reaction times and increased ataxia
Therapeutic Index:
-quantitative index of relative safety of drug defined as LD50/ED50
-larger TI = safer
-since lethal dose should be larger than effective dose, TI should always be greater than 1
-in human trials we use TD (side effects) rather than LD ex TD50/ED50
Safety margin:
-the difference between the dose that will produced a desired effect in most people without producing
some unnaceptable toxic reaction
-most psychoactive compounds have an LD of 1 (dosage required to kill 1% of pop) well above ED95
(dosage that produces desired effect in 95% of pop
