Introduction to pharmacokinetics and pharmacodynamics pdf

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introduction to pharmacokinetics and pharmacodynamics pdf

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Primary goals of clinical pharmacokinetics includeenhancing efficacy and decreasing toxicity of a patientsdrug therapy. The development of strong correlationsbetween drug concentrations and their pharmacologicresponses has enabled clinicians to apply pharmacoki-netic principles to actual patient situations.

Basic Pharmacokinetics and Pharmacodynamics (eBook, PDF)

Primary goals of clinical pharmacokinetics includeenhancing efficacy and decreasing toxicity of a patientsdrug therapy. The development of strong correlationsbetween drug concentrations and their pharmacologicresponses has enabled clinicians to apply pharmacoki-netic principles to actual patient situations.

A drugs effect is often related to its concentration atthe site of action, so it would be useful to monitor thisconcentration. Receptor sites of drugs are generally inac-cessible to our observations or are widely distributed inthe body, and therefore direct measurement of drug con-centrations at these sites is not practical.

For example, the. Obviously we cannot directly sample drugconcentration in this tissue. However, we can measuredrug concentration in the blood or plasma, urine, saliva,and other easily sampled fluids Figure Changes in the plasma drugconcentration reflect changes in drug concentrations atthe receptor site, as well as in other tissues. As the con-centration of drug in plasma increases, the concentrationof drug in most tissues will increase proportionally.

Similarly, if the plasma concentration of a drug isdecreasing, the concentration in tissues will alsodecrease. Figure is a simplified plot of the drug con-centration versus time profile after an intravenous drugdose and illustrates this concept. List the assumptions made about drug distributionpatterns in both one- and two-compartment models. Represent graphically the typical natural log ofplasma drug concentration versus time curve for aone-compartment model after an intravenousdose.

The property of kinetic homogeneity is importantfor the assumptions made in clinical pharmacokinet-ics. It is the foundation on which all therapeutic andtoxic plasma drug concentrations are established. Thatis, when studying concentrations of a drug in plasma,we assume that these plasma concentrations directlyrelate to concentrations in tissues where the diseaseprocess is to be modified by the drug e.

This assumption, however, may not betrue for all drugs. Drugs concentrate in some tissues because of physi-cal or chemical properties. Examples include digoxin,which concentrates in the myocardium, and lipid-soluble drugs, such as benzodiazepines, which con-centrate in fat. The effect of a drug presentat the site of action is determined by that drugs bindingwith a receptor.

Receptors may be present on neurons inthe central nervous system i. For most drugs, the concentration at the site of thereceptor determines the intensity of a drugs effect Fig-ure However, other factors affect drug response aswell.

Density of receptors on the cell surface, the mech-anism by which a signal is transmitted into the cell bysecond messengers substances within the cell , or regu-latory factors that control gene translation and proteinproduction may influence drug effect. This multilevel. In the simplest examples of drug effect, there is a rela-tionship between the concentration of drug at the receptorsite and the pharmacologic effect.

If enough concentra-tions are tested, a maximum effect E. When the logarithm of concentrationis plotted versus effect Figure , one can see that thereis a concentration below which no effect is observed and aconcentration above which no greater effect is achieved. This is referred to as the.

This means that a lesser amount of a more potent drug isneeded to achieve the same effect as a less potent drug. Duration of effect is determined by a complex setof factors, including the time that a drug is engaged onthe receptor as well as intracellular signaling and generegulation. Tolerancemay be caused by pharmacokinetic factors, such asincreased drug metabolism, that decrease the concen-trations achieved with a given dose.

There can also bepharmacodynamic tolerance, which occurs when thesame concentration at the receptor site results in areduced effect with repeated exposure. An example ofdrug tolerance is the use of opiates in the managementof chronic pain. It is not uncommon to find thesepatients requiring increased doses of the opiate overtime. Tolerance can be described in terms of the doseresponse curve, as shown in Figure To assess the effect that a drug regimen is likely tohave, the clinician should consider pharmacokineticand pharmacodynamic factors.

Both are important indetermining a drugs effect. Tolerance can occur with many commonly used drugs. One example is the hemodynamic tolerance that occurswith continued use of organic nitrates, such as nitroglyc-erin.

For this drug, tolerance can be reversed by inter-spersing drug-free intervals with chronic drug use. Relationship of drug concentration at the receptor site to effect as a percentage of maximal effect.

Therapeutic drug monitoring is defined as the use ofassay procedures for determination of drug concentra-tions in plasma, and the interpretation and applicationof the resulting concentration data to develop safe andeffective drug regimens. If performed properly, this pro-cess allows for the achievement of therapeutic concen-trations of a drug more rapidly and safely than can beattained with empiric dose changes. Together withobservations of the drugs clinical effects, it should pro-vide the safest approach to optimal drug therapy.

The usefulness of plasma drug concentration data isbased on the concept that pharmacologic response isclosely related to drug concentration at the site of action. For certain drugs, studies in patients have provided infor-mation on the plasma concentration range that is safeand effective in treating specific diseasesthe therapeu-tic range Figure Within this therapeutic range, thedesired effects of the drug are observed.

Below it, there isgreater probability that the therapeutic benefits are notrealized; above it, toxic effects may occur. No absolute boundaries divide subtherapeutic, thera-peutic, and toxic drug concentrations.

A gray area usu-ally exists for most drugs in which these concentrationsoverlap due to variability in individual patient response. Numerous pharmacokinetic characteristics of a drugmay result in variability in the plasma concentrationachieved with a given dose when administered to vari-ous patients Figure This interpatient variability isprimarily attributed to one or more of the following:. Log in Get Started. Introduction to Pharmacokinetics and Pharmacodynamics. Download for free Report this document.

Embed Size px x x x x Transcript of Introduction to Pharmacokinetics and Pharmacodynamics 1 LESSON 1 Introduction to Pharmacokinetics and Pharmacodynamics Pharmacokinetics is currently defined as the study of thetime course of drug absorption, distribution, metabo-lism, and excretion.

Clinical pharmacokinetics is theapplication of pharmacokinetic principles to the safeand effective therapeutic management of drugs in anindividual patient. For example, the receptor sites for digoxin are thought to be within themyocardium. Kinetichomogeneity describes the predictable relationshipbetween plasma drug concentration and concentration atthe receptor site where a given drug produces its thera-peutic effect Figure Define and differentiate between pharmacokinetics and clinical pharmacokinetics.

Define pharmacodynamics and relate it to pharma-cokinetics. Describe the concept of the therapeutic concentra-tion range. Identify factors that cause interpatient variability indrug disposition and drug response. Describe situations in which routine clinical phar-macokinetic monitoring would be advantageous. Blood is the fluid most often sampled for drug concentration determination.

Relationship of plasma to tissue drug concentrations. Drug concentration versus time. Relationship of drug concentration to drug effect at the recep-tor site. Lesson 1: Introduction to Pharmacokinetics and Pharmacodynamics 3 regulation results in variation of sensitivity to drugeffect from one individual to another and also deter-mines enhancement of or tolerance to drug effects. If enough concentra-tions are tested, a maximum effect E max can be deter-mined Figure When two drugs are tested in the same individual, thedrug with a lower EC 50 would be considered more potent.

The EC 50 does not, however, indicate other importantdeterminants of drug response, such as the duration ofeffect. For some drugs, the effectiveness can decrease withcontinued use. This is referred to as tolerance. Thedrug with a lower EC 50 is considered more potent. Demonstration of tolerance to drug effect with repeated dosing.

This interpatient variability isprimarily attributed to one or more of the following: Va.

Introduction to Pharmacokinetics and Pharmacodynamics

Jetzt bewerten Jetzt bewerten. Updated with new chapters and topics, this book provides a comprehensive description of all essential topics in contemporary pharmacokinetics and pharmacodynamics. DE Als Download kaufen. Jetzt verschenken. In den Warenkorb.

Pharmacokinetics

Download programme here pdf, kB. The role of clinical pharmacology has been well-established in research as well as clinical practice. Its main function in drug development is to establish a dose that is both safe and effective. In this course you will become acquainted with different techniques to describe and predict pharmacokinetics and pharmacodynamics and learn how to apply these techniques in research and clinical practice. The course is organised by the Radboudumc Pharmacy Department and supported by the Radboudumc Department of Pharmacology and Toxicology.

If your institution subscribes to this resource, and you don't have a MyAccess Profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus. Please consult the latest official manual style if you have any questions regarding the format accuracy. Clearance is the most important pharmacokinetic parameter because it determines the steady-state concentration for a given dosage rate. Physiologically, clearance is determined by blood flow to the organ that metabolizes or eliminates the drug and the efficiency of the organ in extracting the drug from the bloodstream. The volume of distribution is a proportionality constant that relates the amount of drug in the body to the serum concentration.

Pharmacokinetics from Ancient Greek pharmakon "drug" and kinetikos "moving, putting in motion"; see chemical kinetics , sometimes abbreviated as PK , is a branch of pharmacology dedicated to determine the fate of substances administered to a living organism. The substances of interest include any chemical xenobiotic such as: pharmaceutical drugs , pesticides , food additives , cosmetics , etc. It attempts to analyze chemical metabolism and to discover the fate of a chemical from the moment that it is administered up to the point at which it is completely eliminated from the body. Pharmacokinetics is the study of how an organism affects a drug, whereas pharmacodynamics PD is the study of how the drug affects the organism.

Basic Pharmacokinetics and Pharmacodynamic Principles

Malaria and tuberculosis TB are two major global diseases mostly affecting the developing countries. Their treatment is often complex because of the drugs used, multidrug resistance, drug interactions and logistic problems such as drug availability and access. Patients are treated for TB for a minimum of 6 months and may concomitantly develop and be treated for malaria, especially during the rainy season.

Pharmacokinetics and pharmacodynamics of propranolol in hypertensive patients after sublingual administration: systemic availability. Mansur, S. Avakian, R. Paula, H. Donzella, S. Santos and J. The bioavailability of propranolol depends on the degree of liver metabolism.

Cancer Chemoprevention pp Cite as. The successful development of new molecules with utility in the prevention and treatment of cancer requires a thorough understanding of the pharmacologic properties of these agents. This includes characterizing their interactions with specific molecular targets and defining their pharmacokinetic and pharmacodynamic properties early in the clinical development process. Pharmacokinetics is the analysis of drug absorption, distribution, metabolism, and excretion. Pharmacodynamics extends these observations by relating time-dependent kinetic processes to actual clinical drug effects including include both therapeutic and toxic drug actions. Therefore, pharmacodynamics is important because it is ultimately the discipline that relates drug pharmacokinetics to clinically relevant endpoints. Unable to display preview.

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