PYB260 Psychopharmacology Revision Table PDF

lOMoARcPSD|33376261 PYB260 - Psychopharmacology Revision Table Psychopharmacology of Addictive Behaviour (Queensland University of Technology) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or unive...

lOMoARcPSD|33376261 PYB260 - Psychopharmacology Revision Table Psychopharmacology of Addictive Behaviour (Queensland University of Technology) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Lonelysoulqi ([email protected])  lOMoARcPSD|33376261 Psychopharmacology The discipline that attempts to systematically study the effects of drugs on behaviour, cognitive functioning, & emotions. Chlorpromazine Effects of antipsychotic effects of chlorpromazine on schizophrenia 1952 discovered. Encouraged researchers to develop new drugs & trial previously abandoned drugs, development of psychopharmacology. 1952-1954: Chlorpromazine the drug of choice for all mental diseases (European trade name: Largasil, Large range of therapeutic activity). Anxiolytic Anxiety-Reducing Agent. First anxiolytic Meprobamate used clinically in 1955, became the most popular drug to treat neuroses (e.g. anxiety). Antidepressants & Mood 1957: First monoamine oxidase inhibitor (MAOI), iproniazide, became Stabilisers widely used as an antidepressant; effect noted in TB patients (1952). First tricyclic antidepressant (imipramine/Tofranil) was used. 1959: Lithium accepted as drug for bipolar mood disorders (1949 Aus discovery, John Cade). Psychopharmacological Magnetic Resonance Imaging (MRI) Revolution Computerized Axial TOmography (CAT) Positron Emission Tomography (PET) Psychotherapeutic drugs don’t cure mental disorders/suppress symptoms in all individuals & potential side effects. Psychotropic By therapeutic action. Classifications Stimulants, Anxiolytic, Sedative-hypnotics, OPiates, ANtidepressants, ANtipsychotics. Drug Any (nonfood, non mechanical) substance that alters the physiology, mood, cognitions, behaviours. Psychoactive Drugs Induces psychological effects by altering normal biochemical reactions in the nervous system. Drug Dosages & Safety Doses given in accordance to body weight (milligrams per kg of body weight). ED50 Median effective dose. Dose that’s effective (produces intended effect) in 50% of individuals tested. LD50 Median lethal dose. The dose that will kill 50% of individuals tested. Therapeutic Index (TI) TI = LD50/ED50 Potency Differences in ED50 between drugs. The lower ED50 the more potent the drug. Effectiveness Differences in the maximum effect that drugs will produce at any dose. Dose-Response/Effect Dose so low there’s no detectable effect, a dose so high that increases in Curve dose have no further effect, & a number of doses in between. Dose indicate on the horizontal axis & effect on the vertical axis. Downloaded by Lonelysoulqi ([email protected])  lOMoARcPSD|33376261 Primary/Main Effect The symptom/disease being treated. Intended treatment effect. Antagonism If one drug diminishes the effect of another drug. Addictive Effect A drug enhances the effect of another drug. When adding the new drug the DRC shifts to the left (e.g. the ED50 decreases). Superadditive/Potentiatio A drug has a greater effect when taken with another drug than might be n Effect expected by simply combing their effects. Side Effect Unintended; may be harmful. Therapeutic Window Range of blood concentrations of a medicine between dose that produces undesirable side effects (toxic level) & dose that has intended effect (therapeutic level). Chemical Name Molecular structure of drugs chemical makeup. The numbers refer to places where different parts of the molecule are joined. Generic Name Aka non-proprietary name. Shorter, simpler name that’s mude up for a drug. Trade Name Aka proprietary name. Name given by drug company, that’s patented for a number of years. Refers to company’s formulation, the active drug ingredient & excipients. Excipients Fillers, colours, binding agents, & coatings. Pharmacokinetics Processes involved in the movement of a drug in the body. Absorption, distribution, & elimination. Absorption How a drug gets into the blood. Distribution Where it goes in the body. Elimination How the drug leaves the body. Sites of Action Most drugs influence the operation of the body only at specific & limited places. Metabolism The process of restructuring (breaking down) molecules; detoxification. Half-life Time taken for the body to eliminate ½ of a given blood level of a drug. Parenteral Route Injection of drug. Subcutaneous (s.c.) Drug is injected just under the skin or cutaneous tissue. Fairly slow & even absorption. Intramuscular (i.m.) Needle is inserted into the muscle, usually upper arm or buttock. Usually absorbed through the muscle’s capillaries within an hour. Intraperitoneal (i.p.) Needle inserted into the peritoneal cavity (sack containing the visceral organs, e.g. liver, intestines, spleen). Needle inserted through stomach Downloaded by Lonelysoulqi ([email protected])  lOMoARcPSD|33376261 muscle & injects drug into cavity that surrounds viscera. Intravenous (i.v.) Needle inserted into the vein & drug administered directly into the Aka Mainlining bloodstream. A vein can’t be used too frequently or it’ll collapse & stop carrying blood. Intracatheal Needle inserted between the base of the skull & the first vertebra (into subarachnoid space so it reaches CSF). E.g. spinal anesthesia. Intracerebroventricular Needle inserted into a cannula inserted into the ventricles of the brain (bypasses blood-brain-barrier). Transdermal Drugs administered through the skin (e.g. nicotine patch). Administration The main barrier to absorption is the epidermis. Can only be penetrated by lipid-soluble substances which absorb very slowly. Intracetal Administration Suppostritries placed in the rectum & the drug is absorbed into the bloodstream. Oral Administration - Drugsm. are swallowed (typically absorbed via digestive system). Peroral (p.o.) E.g. Chewing tobacco isn’t swallowed, the absorption is through the buccal membranes of the mouth & not the digestive system Digestive System The walls of the intestines are lined with capillaries to absorb nutrients & drugs. The drug must first pass through the membrane of the intestinal wall to get the capillaries & be absorbed into the blood through the pores of the capillary walls. Lipid Molecules Has a clump of atoms at one end (the head region & two chains of atoms at the other (the tail region). Lipid molecules in a membrane are organised, so that in each 2 layers the head points outward, towards the intracellular fluid for one layer & toward the extracellular fluid for the other, & tails of each layer point inward toward each other. Heads are hydrophilic (water loving) whereas tails are hydrophobic (water repelling), thus preventing the passage of water soluble substances through the membrane. Inhalation of Gases Allows fast distribution of a drug through the body & to the brain. Quickly absorbed through the capillary walls & enter the circulating blood. Inhalation of Smoke As per gases, but drugs in smoke paricles can’t be exhaled. Intranasal administration Inhalation of solids/powders. Most sniffed drugs are dissolved in the moist mucous membranes of nasal cavities & absorbed into the blood. Capillary To be absorbed into the bloodstream, a drug must pass through the walls of the capillaries. A tiny vessel through which blood flows. Permeates most body tissues. So small in diameter that red blood cells barely pass through. It’s through the capillaries walls that nutrient & oxygen pass out of the blood & into the body tissues. Through these capillary walls waste products & carbon dioxide pass into the blood and are removed. Downloaded by Lonelysoulqi ([email protected])  lOMoARcPSD|33376261 RBC & large protein molecules are the only substances that cant? Move in & out of capillaries. Injected drugs pass into capillaries & the blood through the pores by simple diffusion. Areas with more capillaries will absorb drugs faster, e.g. muscles. The body has approx. 6L of blood & the heart pumps these 6L once a minute, so the drug in most i.v.’s are distributed around the body one minute after injection. Capillary Walls Made of a single layer of cells, between these cells are small openings/ [pres, through which nutrients, waste products & drugs may pass freely. Diffusion The process whereby substance tends to move from an area of high concentration to an area of low concentration until both areas are equal in concentration. Arteries Blood leaves the heart & is distributed around the body in arteries. Divide into smaller & smaller branches until they become capillaries. The blood in capillaries is eventually collected in veins, which carry blood back to the heart & lungs. Depot Drugs Drugs that need to be taken continuously to prevent symptoms from reappearing. Depot Injections Drug is dissolved in high concentrations in vicious oil (often sesame oil) which is then injected into a muscle, usually, the buttock. The drug slowly diffuses from the oil into the bodily fluids over a long period of time. Usually works only with highly lipid soluble drugs, otherwise they’d be released too quickly. Polymer beads degrade slowly in the body & release constance levels of a drug over an extended period of time. Cell Membranes All cells are surrounded by a membrane; lipid bilayer. Each lipid molecule has a clump of atoms (-ve charged heads) at one end & long chains at the other (uncharged tail region); in lipid bilayers, chains (tails) point inward. Large molecules are embedded in the lipid bilayer along the membrane, integral to the flow of information along neurons. For a drug to be absorbed into the body it must be capable of passing through several cell membranes: 1. Dissolve in the lipid molecules (must be lipid soluble) & pass via diffusion or; 2. Be carried through a specialised transporter molecule. Lipid Solubility Drugs that are lipid soluble can pass through cell membranes easily, but drigs that readily dissolve in fats (high lipid solubility) tend to stay in fat & are less effective; released into the bloodstream slowly. Drugs have differing degrees of lipid solubility that are usually expressed in terms of the olive oil partion coefficient. When a molecule of a drug carries an ion, it loses its ability to dissolve in lipids. IOns are umable to pass through membrances. When a drug is dissolved in a liquid, some/all of its molcules in a solution is determined by a) whether the drug is weak acid/weak base, b) whether it’s dissolved in an acid based & c) its pKa (the PH of a drug at which half its Downloaded by Lonelysoulqi ([email protected])  lOMoARcPSD|33376261 molecules are ionised). Protein Binding Some proteins are too large to pass through pores in capillaries. Substances which attach to these proteins may never get to the site of action.. Placental Barrier Substances a mother takes pass through the placental barrier to the feut (high lipid soluble drugs come across more easily). 75-100% of mother’s drug concentration reaches fetus