For many drugs, the gastrointestinal absorption rate, but not the extent of absorption, is reduced by the presence of food in the gut. Cultural or psychosocial factors may affect the ef. Factors affecting drug absorption and distribution. Racial and ethnic differences in response to medicines. Many factors can affect a drug s absorption, distribution, metabolism, excretion, and ultimate effect. Distinguish the effects of changing hemodynamics on drug metabolism and elimination and predict potential pharmaco. U3 actions of drugs factors affecting drug action v4 duration. Although drugs are used primarily for the treatment of disease, surprisingly little is known of the way in which disease states or physiological factors modify drug action in man. Method of administration the manner in which drugs are taken greatly affects the speed, intensity, and duration of effects.
More than half of drugs approved in japan based on asian. Factors affecting drug abuse 2 abstract this article explores factors influencing adolescent female substance use in rural communities. Route determines the speed and intensity of drug response parenteral for speedy action. Genetic and environmental factors affecting drug disposition in man. Factors surrounding the administration of medications may also cause differences in peoples response to drugs. Large interindividual variations in drug response can arise from multiple genetic and environmental factors affecting drug absorption, distribution, biotransformation, excretion, interaction with receptor sites, or combinations of these. Factors modifying drug response variations in response to same dose of a drug between different patients in the same patient on different occasions the dose of drug is generally expressed in the range, which gives therapeutic effect in majority of patients. Evaluate the physiologic changes that affect drug absorption and distribution in critically ill patients.
Gastrointestinal tract physiology and drug absorption. Age is another major factor affecting drug responding. Review synergistic and detrimental drug drug interactions that lead to altered pharmacodynamic responses due to the presence of another drug, a food, or herbal treatment. Drug interactions clinical pharmacology merck manuals. Psychological, social and behavioural factors that. Pathological and physiological factors affecting drug. This spirit of investigation continued through the 20th century and is ongoing today. Overview of response to drugs msd manual consumer version. Genetic factors can account for 20 to 95 percent of.
The article discusses various physiological factors affecting drug metabolism. Factors affecting interindividual differences in clozapine response. Thus, the amount and persistence of available drug at receptor sites change. Exposurerelated, biologic, or chemical factors regulate absorption, metabolism, and elimination, and thus, influence observed clinical consequences. These factors may affect how the body absorbs the drug, how the body breaks down metabolizes and eliminates the drug, or what effects the drug has on the body. Factors affecting drug abuse 9 adolescent substance use in this study. Sep 22, 2017 tolerance requirement of higher dose of a drug to produce a given response refractoriness sulfonylureas in type 2 diabetes and beta2 agonists in bronchial asthma adaptive biological phenomena natural. Factors affecting drug action norma nicholson ba, ma. Factors affecting drug abuse in adolescent females in rural. Start studying factors that determine intensity of drug responses. Toxicosis potential is usually determined more by the multitude of related factors than by actual toxicity of the toxicant. Because so many factors affect drug response, doctors must choose a drug appropriate for each person and must adjust the dose carefully. Pharmacokinetic interactions alter magnitude and duration, not type, of effect.
The effect of these factors on adrs is well documented. The structure of society, the nature of political power, the. An idiosyncratic response is uncommon, and it is sometimes impossible to understand whether it is the result of a genetic predisposition or has some other cause such as the status of the immune. Teens are most likely to follow the crowd, which can have serious consequences when drugs are involved. In order to gain an insight into the numerous factors that can potentially influence the rate and extent of drug absorption into the systemic circulation, a schematic. Padmapattern of adverse drug reactions notified by. Pharmacogenetics involves variations in drug response due to genetic makeup. Physiological factors influencing oral drug absorption. The potential polygenic nature of drug response is illustratview. The interplay between pharmacokinetics and pharmacodynamics. Environmental factors climate, smoking, alcohol consumption, etc. Understand important intrinsic and extrinsic factors affecting drug response. Overview of factors affecting oral drug absorption naining song a,b, shaoy u zhang b, changxiao liu a a tianjin state key laboratory of pharmacokinetics and pharmaco dynamics, tianjin inst. Genetic and environmental factors affecting host response to.
People engage in drug production largely in response to economic incentives, which legal sanctions. Describe two types of drug interaction and explain how they might affect drug response and safety. Clinical drug response represents a complex phenotype that emerges from the interplay of drug specific, human body, and environmental factors. Understand dose response relationships and factors that affect a pharmacological response.
Other factors are gender, race, pregnancy, breast feeding, kidney problems, liver function, drug dose and frequency and many other factors. In the previous chapter, the physiological and pathological factors affecting drug metabolism and how these factors vary in importance was discussed. Some of these factors can be changed like smoking or alcohol intake others cannot be changed like age, presence of other diseases or genetic factors. Cultural, environmental, and genetic influences on drug therapy. A drug may have different actions via different routes magnesium sulfate 7. Factors modifying drug response linkedin slideshare. Variation in the number or function of receptors this may be due to both genetic and environmental factors, hormone responses eg thyroid hormone up regulates beta adrenoceptors in the heart and response to catecholamines, or as a speci. Factors influencing toxicity in some instances, individuals can have unpredictable reactions, or idiosyncratic responses, to a drug or other substance. Biological factors affecting toxic response chemicals in the diet, air or water humans may be under medication with several drugs while exposed to an industrial chemical.
In contrast, extensive studies in laboratory animals have shown that these factors can have striking effects which if applied to man would have enormous clinical. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. In pharmacokinetic interactions, a drug usually alters absorption, distribution, protein binding, metabolism, or excretion of another drug. The factors affecting absorption of drugs are related both to the drugs and to the body. Study factors affecting drug disposition and response flashcards from brittany parsonss class online, or in brainscapes iphone or android app. Density of receptors on the cell surface, the mechanism by which a signal is transmitted into the cell by latory factors that control gene translation and protein. Drugs taken by injection produce effects within 15 seconds because they enter your circulatory system. Intrinsic factors affecting research endocrine factors prolactin. Learn about different concepts such as addition, synergism, and potentiation that lead to an enhancement effect of drugs. Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption. For example, the beneficial natriuresis produced by the loop diuretic. Pathological and physiological factors affecting drug absorption.
Factors that determine intensity of drug responses. Pharmacokinetics, pharmacodynamics, and pharmacogenomics. Learn about agonistic, antagonistic, and partial agonistic binding of drugs to receptors. Pdf factors affecting interindividual differences in. Tdm therapeutic drug monitoring v d volume of distribution table of other common abbreviations. Summary remember the different factors modifying drug actions remember. Sep 02, 2016 factors modifying drug response variations in response to same dose of a drug between different patients in the same patient on different occasions the dose of drug is generally expressed in the range, which gives therapeutic effect in majority of patients. Pharmaceutical factors a chemical factors b physicochemical properties of drug substances. Pharmacodynamic 3 factors affecting drug response youtube. Drugreceptor interactions may be modified by changes in receptor sensitivity, this being influenced by complex regulatory and homeostatic factors. Cultural, environmental, and genetic influences on drug therapy and j. There are 12 questions measuring cigarette, smokeless tobacco, alcohol, marijuana, inhalant, lsd, prescription drug, and cocaine use.
The second dimension that has been largely overlooked is the psychological, social and behavioural factors that influence drug metabolism, efficacy and sideeffects. Factors affecting drug abuse in adolescent females in. Biological factors affecting toxic response human variability toxic response in humans may be very different because of genetic variability of humans. What are the factors affecting the dose and action of drugs. Jul 21, 2017 pharmacodynamic 3 factors affecting drug response. Factors affecting drug responsebiological variability. For example, in the 1950s kalow identified that some patients undergoing electroconvulsive therapy experienced a longer. Variation in the response to equivalent drug concentrations arises because of various factors, such as differences in receptor number and structure, receptorcoupling mechanisms and physiological changes in target organs resulting from differences in genetics, age and health. On average, men are bigger than women and they have a lower proportion of body fat than women. Till now, the most significant biological factors known to affect pharmacokinetics are the drug transporters and the metabolizing enzymes 7,9. Introduction to pharmacokinetics and pharmacodynamics.
Social impacts and policy responses unrisd briefing paper no. Selfreported data gathered from females 12 to 15 years of age in two northwestern communities in the united states showed an association among gender identity, peer and parental relationships, and substance use. Factors affecting drug action drug dosage and theraphy. The toxicity of a chemical in an organism may be increased or decreased by a simultaneous or consecutive exposure to another chemical in food. Variation in response to the same dose of a drug between different patients and even in the same patient on different occasions will occur. Explain how bioavailability can impact drug response and product selection. For most drugs, the concentration at the site of the receptor determines the intensity of a drug s effect figure 14. Some drugs are not affected by food, while the absorption of a third group of drugs is enhanced by food bile secretion by liver in response to food in gi tract increases drug absorption. Drug absorption, drug distribution, drug dissolution, drug solubility introduction. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This complexity results in marked interindividual variation in cardiovascular drug response, affecting both efficacy and toxicity, and leading to patient harm and the inefficient utilization of limited.
Jan 10, 2019 drug effect refers to the normal spectrum of biological response evoked by a drug when used at a recommended dose. Factors affecting drug disposition and response flashcards. The speed with which drugs move in and out of the body varies widely among different people. Nov 15, 2017 since intrinsic ethnic factors are thought to be similar among asian populations, 11 if extrinsic factors such as diagnostic methods and concomitant drug use are controlled, gcts conducted in asian countries may have a higher probability of achieving consistent results than general gcts. A patients expectations can also affect the drug action, a psychological effect called the placebo effect can add to the effectiveness of medication therapy. Amount of drug that exists in unionized form and in ionized form is a function of pka of drug and ph of the fluid at the absorption site, and it can be determined by handersonhasselbach equation. Cultural, environmental, and genetic influences on drug. Factors affecting the longterm response to tacrolimus in.
Pdf pharmacogenetic factors affecting asthma treatment. Compare the roles of passive diffusion and carriermediated transport in drug absorption. Density of receptors on the cell surface, the mechanism by which a signal is transmitted into the cell by latory factors that control gene translation and protein production may in. Pharmaceutical factors a chemical factors b physicochemical properties of drug substances 1. However, other factors affect drug response as well. Pdf overview of factors affecting oral drug absorption. Speciesindividual inherently less sensitive rabbits to atropine and blacks to beta blockers acquired. When receptor sensitivity changes, the same concentration of a drug will produce a greater or lesser physiological response. Individual variation in drug response pharmacology. Called also favism, it is common in persons from mediterranean and african. Some drugs are irritating and should be administered with meals to reduce adverse effects. Men and women respond differently to drugs for various reasons.
The factors determining racial variations in response to medications are complex and interdependent. Factors modifying drug action general pharmacology. As we know, these factors affect the distribution of drugs in the body. Species and race species variation in drugs responses do exist some strains of. Genetic and environmental factors affecting drug disposition. Drug receptor interactions an overview sciencedirect topics. The biological makeup of the person genetics, conditions at home, school or neighborhood and a persons developmental stage are examples of some of the factors that may lead to drug abuse 1. In order to describe the phenomenon as well as to differentiate it from psychopharmacology, we here coin a new term.
Genetic factors in drug metabolism american family physician. Therefore, in order to get the best possible treatment, it is important that your healthcare professional factors in all these elements before prescribing a drug. Drug response can be impacted by several factors including diet. Drugs which are inhaled or smoked take from 5 to 10 seconds to produce effects. Factors affecting the activity of toxicants toxicology. Most answers are recorded using seven responses that ranged from no occasions 1 to. Pharmacogenetics clinical pharmacology merck manuals. The usual adult dose of medication as listed in standard references, is based on the assumption that the adult weighs 150.
Many factors can affect a drugs absorption, distribution, metabolism, excretion, and ultimate effect. Pdf factors affecting the development of adverse drug. Large interindividual variations in drug response can arise from multiple genetic and environmental factors affecting drug absorption, distribution. Drug response can be affected by a wide range of factors, including genetics, age and certain environmental considerations. In general, children require smaller doses than adults. Either youngs formula based on age or clarks formula based on weight can be used for calculating the doses for children but the formula based on body surface area is more reliable. There are, however, factors from outside the body that can also have a profound influence on drug metabolism. Adr is defined as a response to a drug which is noxious and unintended. Glucose6phosphate dehydrogenase deficiency g6pd is xlinked genetic condition that predispose to hemolytic anemia. Pepsins and the proteases are responsible for the degradation of protein and peptide drugs in the lumen.
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