DRUGS BRAIN BEHAVIOR
DRUGS BRAIN BEHAVIOR PSYC 4035
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This 4 page Class Notes was uploaded by Clementine Boehm on Tuesday October 13, 2015. The Class Notes belongs to PSYC 4035 at Louisiana State University taught by C. Advokat in Fall. Since its upload, it has received 23 views. For similar materials see /class/222961/psyc-4035-louisiana-state-university in Psychlogy at Louisiana State University.
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Date Created: 10/13/15
Test 1 Study Guide 0 Pharmacology the science of drugs 0 Derived from the Greek 39pharmacon medication potion poison 0 Why and how does a drug act 0 What is a drug 0 Drug from the French 39drogue dry powder 0 A nonfood chemical used to alter one or more normal biological processes in animals 0 Psychoactive drugs act on nervous system to alter biological processes I Problems have worsened in the last 200 years why o Acceptability o Vaccines controlled communicable diseases 0 Antibiotics controlled infectious diseases I Created other problems I Strains on which they are ineffective 0 Psychiatric drugs shift from physical to mental o Contraceptives shift from unhealthy quotillquot body to healthy body 0 Recreational drugs shift from physical to mental in healthy brain 0 Accessibility 0 Democratization of privilege quotdisorders of volition gambling sexual revolution eating disorders etc voluntary behaviors I Hundreds of years ago these weren t an option no money to gamble no contraceptives thus less promiscuity bc pregnancy was a risk 0 Scientific advances more powerful formulations I Invention of hypodermic syringe civil war times morphine addiction first addiction using it soldiers Discovery of chemical structure and synthesis of more potent manmade formulations Raise questions ofhow to regulate and control use especially for reasons ofvolition Denotes shift in use of drugs Shift from physical to mental and behavioral causes for drug use Not as easy to point to something concrete 0 Pharmacokinetics what your body does to the drugs processes involved in the movement of drugs in biological systems application of mathematics to predict the rate of change of the drug in the body 0 ADME pneumonic I Absorption movement of drug from site of administration to the blood 0 Major routes of administration 0 Parenteralnot involving the digestive tract I Common types 0 Subcutaneous under skin 0 Intramuscular into a muscle 0 Intravenous into vein I Advantages can easily adjust dose I Disadvantage may not be able to reverse an overdoes unless antidote is available 0 Enteraldigestive tract oral or rectal usually means by mouth peroral pp but not always I Chewing tobacco drug absorbed by buccal mucous membrane I Nitroglycerin under the tongue I Suppositories in rectum vaginaparenteral also absorbed into the blood useful is individual is unconscious or vomiting I Pros and Cons of ENTERAL route 0 Disadvantages 0 Individual must be conscious o Nausea and vomiting will prevent absorption 0 Variability absorption is unpredictable 0 Advantages 0 Easy 0 Safe 0 Other routes 0 Factors affecting absorption ENTERAL o Solubility partition coefficient how easily drug molecules pass into the cells To get to capillaries drug must pass through intestinal wall which is made up oflipids fats There are no pores in stomach or intestine lining The more lipid soluble a drug the easier it can pass through the intestinal walls into the blood Partition coefficient measure of lipid solubility o Determined by putting known amount of drug into a container with oil and water which separate out and some drug molecules in each part 0 If fat soluble many drug molecules in oil 0 If water soluble many in water 0 Look for relationship concentration of drug in oilconcentration of drug in water 0 That numeric relationshippartition coefficient 0 Higher the partition coefficient the easier it is for drug to pass through any membranes especially the guy thus works faster 0 Ionization coefficient An ion is a charged molecule Ions are not lipid soluble o Membranes of the body have proteins embedded 0 Proteins have mixtures of and charges 0 These tend to repel other charged particles 0 Nonionized particles are neutral amp pass more easily across membranes 0 When drug dissolved in uid some or all ofits molecules become ionized Therefore an ionized drug is less soluble because has to overcome electrical environment of the gut High ionization coefficientless soluble 0 First pass effect I Before the blood goes to the rest of the body from the GI gastrointestinal tract it passes through the liver detox center The liver is the major organ that breaks down drugs Therefore a certain amount of drug will be inactivated or metabolized as it goes through the liver Other routes may not be subject to this quotfirst pass effect Ways around this effect 0 Under the tongue 0 Patches 0 New Ritalin in patch form goes straight to blood stream thus might need to modify the dosage 0 Also provides a staple dose level in the blood more standard and less variability in drug distribution 0 For absorption drug must pass through capillary walls Walls consist of single layer of cells There are holes or pores between these cells Nutrients waste and drugs move through the pores Red blood cells and large protein molecules are too big Injected drugs move through he capillaries and blood by diffusion through pores o Distribution movement of drug from blood to rest ofbody o Binding attachment of drug to its site ofaction to produce its effect 00000 0 Distribution 0 Drug molecules can be found in different places in the blood I Plasma more likely with water soluble drugs I Platelets more likely with lipid soluble drugs I Attached to proteins ie albumin egg whites 0 Bound vs free 0 Bound molecules are trapped I Only free molecules can leave the circulation I Free drug is the active drug 0 As free drug is used and metabolized more bound drug is released 0 Saturation point when all binding sites are filled o Ifmore drug comes in will be in free form and thus active 0 More than one drug present may displace one another 0 Example if100 binding sites given I 100 unites bound100 I 200 given 50 bound I 400 given 25 bound 0 CATCH UP 0 Biotransformation metabolism chemical changes that usually reduce the effect of drugs and increase their excretion o Kidneys filter waste from blood collect it in the bladder o Lipid soluble o The liver protects the body from toxic substances I Contains enzyme systems that can detoxify harmful substances I Changes highly lipid soluble to less lipid soluble I More likely to ionize I May produce another lipid soluble molecule an quotactive metabolite not excreted but active benzodiazepines ie tranquilizers like valium I Substances that transform drugs are enzymes proteins I Most are nonspecific I Located on the part of the liver cell called the smooth endoplasmic reticulum SER I Referred to as the microsomal enzymes main category cytochrome P450 0 Cytochrome P450 SER on microsomal enzyme layer when liver cells opened in centrifuge o P refers to the particle enzyme 0 450 is nanometers referring to light waves enzymes absorb o 2 major phases of drug metabolism I Phase 1 and Phase 2 I Phase 1 usually cytochrome P450 aka CYP I Most concentrated in liver I There are about 12 CYP families 0 CYP1 2 and 3 most common for drug metabolism o CYP2D6 and CYP3A especially 34A metabolize over 50 of drugs 0 Drug companies need to know this 0 What are pharmacokinetic aspects of drugs I Many factors in uence cytochrome P450 enzyme activities 0 Disease especially of the liver can t filter or metabolize drugs 0 Species not all species have same profile of enzymes 0 Age changes in young and old 0 Infants and babies not able to metabolize I Often exposed to a drug longer than adults because they cannot metabolize as fast I Often more affected by drugs than adults 0 Older more diseases liver kidneys water control changes in duration it takes for drugs to move through 0 Size and surface area of body rats faster than cats Must be aware when testing on animals 0 Genetics differ greatly in ability to metabolize drugs 0 More enzymes than others 0 Better enzymes Enzyme Induction 0 Past experience with drugs will affect the enzyme systems 0 Enzyme Induction Levels of enzymes can be increased by previous exposure to a specific drug 0 Take drug for months 0 Must have certain amount in body 0 As drug continues to come in liver reacts and begins to produce more of that enzyme to compensate and metabolize the drug that is taken over time 0 Must be careful when stop taking have more enzyme than you started with Anything else in body will be metabolized more quickly because more enzyme and less drug St John s Wort hypoforin proposed as natural antidepressant stimulates a receptor PXR in nonhumans SXR in humans in the liver to induce CYP3A which then breaks down many other drugs theophylline asthma warfarin anticlotting birth control pills and immunosuppressant cyclosporin OO
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