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Sesion 2 pharm1
Pharm -1- Pharmacokinetics clinical pharmacology
Question | Answer |
---|---|
What does ADME stand for | Absorption, Distribution, Metabolism(Biotransformation), and Excretion |
What is meant by normality | Assuming the patient has normal functioning organs especially liver and kidney |
A disorder in which organ system would most likely effect absorption of drugs | GI tract |
Why is knowing pharmacokinetics so important | allows effective medication prescribing |
What is the goal at the target organ when administering drugs | reaching a sustained drug concentration |
What is responsible for the distribution portion of the ADME model of pharm | Blood Plasma |
What is the organ responsible for drug excretion | Kidney |
What are the 4 processes that we must have an understanding of with pharmacotherapy. Hint 1st one deals with compliance | 1)Pharmaceutical process:drug getting into patient 2)Pharmacokinetic Process: drug getting to site of action (absorption/distribution) 3)Pharmacodynamic Process: drug producing pharmacologic effects(desensitization) 4)Therapeutic Process: getting resul |
What is the rational/way of thinking when prescribing drugs | 1st which drug group to use 2nd which specific drug 3rd dosage 4th regimen |
What are things that will effect your drug prescribing | Patient Variables pediatric (dosage calculation) Geriatric (go low go slow) Polypharm pathological condition (is the patient not in a normality) Pregnancy |
What needs to occur first to allow you to prescribe correctly Hint first one deals with accurate something | 1)Accurate Diagnosis 2) know pathophysiology of disease 3)know basic pharmacology and kinetics of drugs in normal and diseased patients 4)translate above into bedside action |
What are the different routes of administration in order of fastest absorption and distribution | IV, IM, Sub Q, Oral/Anal, |
What are the advantages to IV admin | immediate absorption, rapid distribution, allows titration, bypasses caustic stomach, reduces irritation, can be given to unconscious patients |
What are the disadvantages to IV admin | once given can't be removed, possible infection, discomfort, requires skilled admin easy overdose, allergy and irritation |
****What is Drug Bioavailability | fraction of unchanged drug that reaches systemic circulation. IE how much of the drug survives first pass metabolism in portal circulation. |
How is bioavailability measured | Compare level of drug after administration with levels of drug if you did IV admin |
What is First Pass Metabolism | oral administration absorbs through GI tract which goes to portal circulation which first goes through liver for metabolism before going to systemic circulation for distribution |
What drug factors affect bioavailability | Drug Solubility- lipophilic drugs get absorped better, molecular weight/size Chemical Stability- can it survive low pH of stomach Drug Formulation- particle size, salt form, etc |
List the routes of administration from highest to lowest bioavailability | IV(100)(R), Transdermal (80-100)slow sustained, IM (75-100), Sub Q (75-100), Rectal (30-100), Oral (5-80), Inhalation (5-100) low because poor administration. |
What is drug 1/2life T1/2 | time it takes to reduce plasma concentration of drug by 50% only works for 1st order drugs and as long as you don't exceed bodies elimination systems. |
What is a steady state of drug admin and how many half lives does it gen take to reach it | balance between elimination and input of drug so you get a constant drug concentration in plasma. need 4-5 half lives to reach steady state |
What is a therapeutic window | the dosage between minimum effective concentration(trough) and minimum toxic level(peak). Some drugs have a large therapeutic window others a small window. |
When do you need to redose a patient | before you drop back below minimum effective concentration |
What are the four mechanisms for absorption | Passive diffusion Active transport filtration through pores pinocytosis |
what are the characteristics of passive diffusion | no energy, drug moves according to concentration gradient, Lipis soluble drugs absorb more readily. Most drugs are lipid soluble and use passive diffusion |
What are the characteristics of active transport | Uses energy in form of ATP, Highly Specific, uses specific carrier proteins, Saturable. Places that use active transport alot Brain and Placenta |
What is Drug distribution | process by which drug leaves blood and enters interstitium, |
What effects drug distribution | blood flow, capillary permeability, drug binding to plasma proteins |
How effectively can drugs bind to plasma albumin and why is this important with drug administration | upto 98% binding such as with warfarin which if you have a patient take another drug it could know the warfarin off the albumin and cause toxic effects |
What is Alpha acid glycoprotein AAG | another plasma protein that binds drugs |
What is volume of distribution | equals Dose/blood concentration of the drug. is amount of drug in body vs amount of drug in the blood |
What is biotransformation | metabolism of the drug in the body major mode for drug elimination |
What is a prodrug | drug that needs to be metabolized to activate it |
what is the major site of metabolism | liver |
What can effect biotransformation of a drug | Prior Administration of a drug, physiological status of patient, age , genetics and liver function |
What can biotrasformation/metabolism result in the drug being changed into. IE inactive metabolite | make inactive metabolite, toxic metabolite, active metabolite, change potency, change drug actions. |
What is the major cytochrome for biotransformation phase 1 | Cytochrome P450 |
What does cytochrome 3A4 do and what are some of the other cytochromes | pretty much metabolizes everything 70% of drugs, others are 1A2, 2A6, 2C19 |
Phase 2 biotransformation involves what 4 catalyzing agents | glucuronyl transferase, sulfotransferase, transacylases, inacivation of and increased water solubility of drugs. |
What Drugs does Glucoronidation take care of | acetaminophen, diazepam, morphine |
What drugs does sulfate conjugation by sulfotransferase take care of | acetaminophen, methyldopa |
What drugs does acetylation take care of and what condition can result if you are a poor acetylater | Isoniazid, sulfonamides, slow acetylators can develop drug induced SLE especially from Hydralazine, Isonazid, procainazide |
What is the average GFR | 125 ml/min |
What is net renal excretion | drug filitered at glomerulus+drug actively transported - drug passively reabsorbed throughout tubule |
How are drug elimination and excretion different | Drugs can be eliminated by metabolism which modifies them, excretion is removing unmodified/metabolized drugs from the body |
What is Zero Order Elimination | drug is eliminated at a constant rate regardless of concentration |
What is clearance | volume of plasma that is cleared of a drug per unit time. can be by excretion or metabolism |
What is a first order elimination | drug is eliminated in proportion to its concentration increase concentration increase elimination most drugs follow first order kinetics |
What can effect biotransformation of a drug | Prior Administration of a drug, physiological status of patient, age , genetics and liver function |
What can biotrasformation/metabolism result in the drug being changed into. IE inactive metabolite | make inactive metabolite, toxic metabolite, active metabolite, change potency, change drug actions. |
What is the major cytochrome for biotransformation phase 1 | Cytochrome P450 |
What does cytochrome 3A4 do and what are some of the other cytochromes | pretty much metabolizes everything 70% of drugs, others are 1A2, 2A6, 2C19 |
Phase 2 biotransformation involves what 4 catalyzing agents | glucuronyl transferase, sulfotransferase, transacylases, inacivation of and increased water solubility of drugs. |
What Drugs does Glucoronidation take care of | acetaminophen, diazepam, morphine |
What drugs does sulfate conjugation by sulfotransferase take care of | acetaminophen, methyldopa |
What drugs does acetylation take care of and what condition can result if you are a poor acetylater | Isoniazid, sulfonamides, slow acetylators can develop drug induced SLE especially from Hydralazine, Isonazid, procainazide |
What is the average GFR | 125 ml/min |
What is net renal excretion | drug filitered at glomerulus+drug actively transported - drug passively reabsorbed throughout tubule |
How are drug elimination and excretion different | Drugs can be eliminated by metabolism which modifies them, excretion is removing unmodified/metabolized drugs from the body |
What is Zero Order Elimination | drug is eliminated at a constant rate regardless of concentration |
What is clearance | volume of plasma that is cleared of a drug per unit time. can be by excretion or metabolism |
What is a first order elimination | drug is eliminated in proportion to its concentration increase concentration increase elimination most drugs follow first order kinetics |