Exam 1 Mental Health Chapter 12

Chapter 12 Introduction to psychotropic drugs Types!of!psychotropic!drugs! -Treat delusions & hallucinations -Slow down run away thinking -Improve mood -Calm nerves -Improve thinking -Correct problems caused by antipsychotic 6 POINTS MUST BE MADE 1. Drugs are not always warranted 2. Drugs are not always effective 3. Effective optimal outcomes typically occur when other interventions are coadmin 4. Psychotropic agents can be used to avoid the hard work of getting better 5. Many psychotropic drugs have significant or even life-threatening side effects, dr interactions, or both 6. Finding the right drug regimen is often a trial & error exercise Nursing!Responsibilities! -Psychopharmacology is the second component of the psychotherapeutic management -The nurse must understand key dimensions of psychotropic drug use -Resposible for assessing drug side effects, evaluating desired effects, & applying prev care to reduce potential problems -Nurses determine the use of PRN medications Pharmacokinetics! -Defined as the effects that the body has on a drug -Getting the drug into the bloodstream -Drugs taken orally must get out of the GI tract & into bloodstream to have an effect >drug must pass through stomach or small intestine into blood vessels >molecules pass through cell membrane -The percentage of an oral drug that reaches systemic circulation is called bioavailabili -100% of IV drugs reach systemic circulation -Getting the drug from the bloodstream to tissues & organs -Lipid soluble molecules can penetrate capillary membranes as easily as other cell mem -Water soluble molecules leave circulation because of significant gaps between cells of capillary walls -Protein binding is another issue; most drugs bind to plasma proteins (albumin) >molecules that are bound to protein cannot leave circulation because the protein is large to pass through capillary wall -Diazepam is a 98% protein binding medication -Breaking the drug down into an inactive & typically water soluble form -Most drugs are metabolized to inactive states in preparation for excretion through uri -Not all drugs are broken down or converted to water soluble or excreted through urin -Most metabolism occurs in the liver; some in lungs, kidneys, GI tract, & plasma -Enzymes facilitate metabolic processes >Monoamine Oxidase System: metabolizes monoamines (dopamine, norepinephrin serotonin) >Cytochrome P-450: most drug interactions occur -Half life of a drug is the amount of time required for 50% of the drug to disappear fro body; if drug X has a half life of 4 hours, then 50% of the drug will be out of the sy in 4 hours (linear kinetics) -When discontinuing a drug, 4 half lives are required to eliminate 96% of drug; “ -Getting the drug out the body breast milk, bile, feces, saliva, sweat, lungs Pharmacodynamics! -Defined as the effect that a drug has on the body >agonists: drugs that activate receptors >antagonists: drugs that block receptors -Chronic exposure to certain psychotropic drugs causes receptors to change -Consistent use of antidepressants causes postsynaptic receptors to decrease in numbe -Pharmacodynamic interactions occur when one of the four pharmacokinetic processe inhibited or induced >absorption: drug A is taken with another drug that changes stomach pH, affecti absorption of drug A >distribution: 2 drugs are both highly protein-bound; drug A “hogs” most of the sites, leaving more of drug B available. Drug B would then have a greater pharmacologic effect >metabolism: 2 drugs are metabolized by the CYP-450 enzyme 2D6; one or both drugs could have a higher blood. Level >excretion: drug A alters the urinary pH, speeding or hindering the excretion of -Enzyme induction usually takes several days to weeks to develop, whereas enzyme inhibition develops almost immediately The!Blood-Brain!Barrier! -The brain requires a constant internal milieu that protects the brain from fluctuation i chemistry; even the smallest changes in the brain produce serious problems -This barrier regulates the amount & speed of substances in the blood entering the bra -The BBB has 3 dimensions: 1. Anatomic dimension: structure of the capillaries that supply blood to the brain & molecules from slipping thought; no gaps 2. Physiologic dimension: chemical & transport system that recognizes & allows c molecules into the brain; lipid solubility determines whether a molecule can pas BBB; highly lipid soluble pass with great ease; highly water soluble penetrate th slowly & insignificant amounts 3. Metabolic dimension: prevents molecules form entering the brain by enzymatic within the endothelial lining of brain capillaries **P-glycoprotein efflux transporter system is another dimension of the physiologic dim -Contains various substrates -Ferries molecules back out of the cell as fast as they enter -Can cause a second generation antihistamine to be nonsedating -Drugs that induce the P-glycoprotein system cause the drug to be less effective -Drugs that inhibit P-glycoprotein can cause an increased central effect without cha serum levels Neurons!&!Neurotransmitters! -Information in the form of an electrochemical excitation is communicated between ce specific manner -Electrochemical impulses run from the cell body through the axon to synaptic termina -Neurotransmitters are stimulated & released from synaptic terminal & combine with r in postsynaptic neuron = a neuronal response Patient!Education! -Many hospitalizations are related to patients nonadherance to medications >reasons for nonadherance: lack of knowledge; lack of insight; negative reaction to in past; feeling better, thus thinking that med. is not needed; side effects; complic dosing; sexual dysfunction; religious reasons; pregnancy; inability to use alcohol -Specific areas of education include the following: >discuss side effects >instructions for pregnant or BF moms >discuss safety issues >awareness of metabolic differences in >attitudes of patients & nurse diverse races or ethnicities >drug interactions >instructions for older patients or children