{"id":25,"date":"2021-12-07T07:20:21","date_gmt":"2021-12-07T07:20:21","guid":{"rendered":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/?post_type=chapter&#038;p=25"},"modified":"2021-12-08T07:13:20","modified_gmt":"2021-12-08T07:13:20","slug":"1-2-pharmacokinetics","status":"publish","type":"chapter","link":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/chapter\/1-2-pharmacokinetics\/","title":{"raw":"1.2 Pharmacokinetics","rendered":"1.2 Pharmacokinetics"},"content":{"raw":"<h2>Pharmacokinetics \u2013 Examining the Interaction of Body and Drug<\/h2>\r\n<h3>Overview<\/h3>\r\n<strong><button class=\"glossary-term\" aria-describedby=\"190-91\">Pharmacokinetics<\/button><\/strong>\u00a0is the term that describes the four stages of absorption, distribution, metabolism, and excretion of drugs.\u00a0\u00a0<strong>Drugs<\/strong>\u00a0are medications or other substances that have a physiological effect when introduced to the body. There are four basic stages for a medication to go through within the human body: absorption, distribution, metabolism, and excretion. This entire process is sometimes abbreviated\u00a0<strong>ADME.\u00a0\u00a0<\/strong><strong>Absorption<\/strong>\u00a0occurs after medications enter the body and travel from the site of administration into the body\u2019s circulation.\u00a0\u00a0<strong>Distribution<\/strong>\u00a0is the process by which medication is distributed throughout the body.\u00a0\u00a0<strong>Metabolism<\/strong>\u00a0is the breakdown of a drug molecule.\u00a0<strong>Excretion<\/strong>\u00a0is the process by which the body eliminates waste.\u00a0 Each of these stages is described separately later in this chapter.\r\n\r\nResearch scientists who specialize in pharmacokinetics must also pay attention to another dimension of drug action within the body: time. Unfortunately, scientists do not have the ability to actually see where a drug is going or how long it is active. To compensate, they use mathematical models and precise measurements of blood and urine to determine where a drug goes and how much of the drug (or breakdown product) remains after the body processes it. Other indicators, such as blood levels of liver enzymes, can help predict how much of a drug is going to be absorbed.\r\n\r\nPrinciples of chemistry are also applied while studying pharmacokinetics because the interactions between drug and body molecules are really just a series of chemical reactions. Understanding the chemical encounters between drugs and biological environments, such as the bloodstream and the oily surfaces of cells, is necessary to predict how much of a drug will be metabolized by the body.\r\n\r\n<strong>Pharmacodynamics<\/strong>\u00a0refers to the effects of drugs in the body and the mechanism of their action.\u00a0 As a drug travels through the bloodstream, it will exhibit a unique\u00a0<strong><button class=\"glossary-term\" aria-describedby=\"190-126\">affinity<\/button><\/strong>\u00a0for the drug-receptor site, meaning how strongly it will bind to the site. \u00a0Examination of how drugs and receptor sites create a lock and key system (see Figure 1.1<a id=\"return-footnote-190-1\" class=\"footnote\" title=\"&quot;Drug and Receptor Binding&quot; by Dominic Slausen at Chippewa Valley Technical College is licensed under CC BY 4.0\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#footnote-190-1\" aria-label=\"Footnote 1\"><sup class=\"footnote\">[1]<\/sup><\/a>) is helpful to understand how drugs work and the amount of drug that may be left circulating within the bloodstream.\u00a0 This concept is broadly termed as drug\u00a0<strong><button class=\"glossary-term\" aria-describedby=\"190-93\">bioavailability<\/button><\/strong>.\u00a0 The bioavailability of drugs is an important feature that chemists and pharmaceutical scientists keep in mind when designing and packaging medicines. Unfortunately, no matter how effectively a drug works in a laboratory simulation, the performance in the human body will not always produce the same results, and individualized responses to drugs have to be considered. Although many responses to medications may be anticipated, one\u2019s unique genetic makeup may also have a significant impact on one\u2019s response to a drug.\u00a0<strong><button class=\"glossary-term\" aria-describedby=\"190-94\">Pharmacogenetics<\/button><\/strong>\u00a0is defined as the study of how people\u2019s genes affect their response to medicines.<sup><a id=\"return-footnote-190-2\" class=\"footnote\" title=\"This work is a derivative of Medicines by Design by US Department of Health and Human Services, National Institute of Health, National Institute of General Medical Sciences and is available in the public domain.\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#footnote-190-2\" aria-label=\"Footnote 2\"><sup class=\"footnote\">[2]<\/sup><\/a><\/sup>\r\n<figure id=\"attachment_6938\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-6938\"><img class=\"wp-image-6938\" title=\"Drug and Receptor Binding&quot; by Dominic Slausen at Chippewa Valley Technical College is licensed under CC BY 4.0\" src=\"https:\/\/wtcs.pressbooks.pub\/app\/uploads\/sites\/10\/2019\/09\/Drug-Binding-Barrier-Animation-1.gif\" alt=\"Animated image of drug binding to receptor\" width=\"521\" height=\"391\" \/><figcaption id=\"caption-attachment-6938\" class=\"wp-caption-text\">Figure 1.1 Pharmacodynamics: Drug and Receptor Binding<\/figcaption><\/figure>\r\n&nbsp;\r\n\r\n<hr class=\"before-footnotes clear\" \/>\r\n\r\n<div class=\"footnotes\">\r\n<ol>\r\n \t<li id=\"footnote-190-1\">\"<a href=\"https:\/\/wlresources.dpi.wi.gov\/courses\/drug-and-receptor-binding\/view\" target=\"_blank\" rel=\"noopener noreferrer\">Drug and Receptor Binding<\/a>\" by Dominic Slausen at\u00a0<a href=\"https:\/\/www.cvtc.edu\/\" target=\"_blank\" rel=\"noopener noreferrer\">Chippewa Valley Technical College<\/a>\u00a0is licensed under\u00a0<a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>\u00a0<a class=\"return-footnote\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#return-footnote-190-1\" aria-label=\"Return to footnote 1\">\u21b5<\/a><\/li>\r\n \t<li id=\"footnote-190-2\">This work is a derivative of\u00a0<a href=\"https:\/\/open.bccampus.ca\/browse-our-collection\/find-open-textbooks\/?uuid=81f9ddbb-b946-400e-ac10-9afd71c47e32&amp;contributor&amp;keyword&amp;subject=Pharmacy%2FPharmacology\" target=\"_blank\" rel=\"noopener noreferrer\">Medicines by Design<\/a>\u00a0by US Department of Health and Human Services, National Institute of Health, National Institute of General Medical Sciences and is available in the public domain.\u00a0<a class=\"return-footnote\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#return-footnote-190-2\" aria-label=\"Return to footnote 2\">\u21b5<\/a><\/li>\r\n<\/ol>\r\n<\/div>","rendered":"<h2>Pharmacokinetics \u2013 Examining the Interaction of Body and Drug<\/h2>\n<h3>Overview<\/h3>\n<p><strong><button class=\"glossary-term\" aria-describedby=\"190-91\">Pharmacokinetics<\/button><\/strong>\u00a0is the term that describes the four stages of absorption, distribution, metabolism, and excretion of drugs.\u00a0\u00a0<strong>Drugs<\/strong>\u00a0are medications or other substances that have a physiological effect when introduced to the body. There are four basic stages for a medication to go through within the human body: absorption, distribution, metabolism, and excretion. This entire process is sometimes abbreviated\u00a0<strong>ADME.\u00a0\u00a0<\/strong><strong>Absorption<\/strong>\u00a0occurs after medications enter the body and travel from the site of administration into the body\u2019s circulation.\u00a0\u00a0<strong>Distribution<\/strong>\u00a0is the process by which medication is distributed throughout the body.\u00a0\u00a0<strong>Metabolism<\/strong>\u00a0is the breakdown of a drug molecule.\u00a0<strong>Excretion<\/strong>\u00a0is the process by which the body eliminates waste.\u00a0 Each of these stages is described separately later in this chapter.<\/p>\n<p>Research scientists who specialize in pharmacokinetics must also pay attention to another dimension of drug action within the body: time. Unfortunately, scientists do not have the ability to actually see where a drug is going or how long it is active. To compensate, they use mathematical models and precise measurements of blood and urine to determine where a drug goes and how much of the drug (or breakdown product) remains after the body processes it. Other indicators, such as blood levels of liver enzymes, can help predict how much of a drug is going to be absorbed.<\/p>\n<p>Principles of chemistry are also applied while studying pharmacokinetics because the interactions between drug and body molecules are really just a series of chemical reactions. Understanding the chemical encounters between drugs and biological environments, such as the bloodstream and the oily surfaces of cells, is necessary to predict how much of a drug will be metabolized by the body.<\/p>\n<p><strong>Pharmacodynamics<\/strong>\u00a0refers to the effects of drugs in the body and the mechanism of their action.\u00a0 As a drug travels through the bloodstream, it will exhibit a unique\u00a0<strong><button class=\"glossary-term\" aria-describedby=\"190-126\">affinity<\/button><\/strong>\u00a0for the drug-receptor site, meaning how strongly it will bind to the site. \u00a0Examination of how drugs and receptor sites create a lock and key system (see Figure 1.1<a id=\"return-footnote-190-1\" class=\"footnote\" title=\"&quot;Drug and Receptor Binding&quot; by Dominic Slausen at Chippewa Valley Technical College is licensed under CC BY 4.0\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#footnote-190-1\" aria-label=\"Footnote 1\"><sup class=\"footnote\">[1]<\/sup><\/a>) is helpful to understand how drugs work and the amount of drug that may be left circulating within the bloodstream.\u00a0 This concept is broadly termed as drug\u00a0<strong><button class=\"glossary-term\" aria-describedby=\"190-93\">bioavailability<\/button><\/strong>.\u00a0 The bioavailability of drugs is an important feature that chemists and pharmaceutical scientists keep in mind when designing and packaging medicines. Unfortunately, no matter how effectively a drug works in a laboratory simulation, the performance in the human body will not always produce the same results, and individualized responses to drugs have to be considered. Although many responses to medications may be anticipated, one\u2019s unique genetic makeup may also have a significant impact on one\u2019s response to a drug.\u00a0<strong><button class=\"glossary-term\" aria-describedby=\"190-94\">Pharmacogenetics<\/button><\/strong>\u00a0is defined as the study of how people\u2019s genes affect their response to medicines.<sup><a id=\"return-footnote-190-2\" class=\"footnote\" title=\"This work is a derivative of Medicines by Design by US Department of Health and Human Services, National Institute of Health, National Institute of General Medical Sciences and is available in the public domain.\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#footnote-190-2\" aria-label=\"Footnote 2\"><sup class=\"footnote\">[2]<\/sup><\/a><\/sup><\/p>\n<figure id=\"attachment_6938\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-6938\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-6938\" title=\"Drug and Receptor Binding&quot; by Dominic Slausen at Chippewa Valley Technical College is licensed under CC BY 4.0\" src=\"https:\/\/wtcs.pressbooks.pub\/app\/uploads\/sites\/10\/2019\/09\/Drug-Binding-Barrier-Animation-1.gif\" alt=\"Animated image of drug binding to receptor\" width=\"521\" height=\"391\" \/><figcaption id=\"caption-attachment-6938\" class=\"wp-caption-text\">Figure 1.1 Pharmacodynamics: Drug and Receptor Binding<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<hr class=\"before-footnotes clear\" \/>\n<div class=\"footnotes\">\n<ol>\n<li id=\"footnote-190-1\">&#8220;<a href=\"https:\/\/wlresources.dpi.wi.gov\/courses\/drug-and-receptor-binding\/view\" target=\"_blank\" rel=\"noopener noreferrer\">Drug and Receptor Binding<\/a>&#8221; by Dominic Slausen at\u00a0<a href=\"https:\/\/www.cvtc.edu\/\" target=\"_blank\" rel=\"noopener noreferrer\">Chippewa Valley Technical College<\/a>\u00a0is licensed under\u00a0<a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>\u00a0<a class=\"return-footnote\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#return-footnote-190-1\" aria-label=\"Return to footnote 1\">\u21b5<\/a><\/li>\n<li id=\"footnote-190-2\">This work is a derivative of\u00a0<a href=\"https:\/\/open.bccampus.ca\/browse-our-collection\/find-open-textbooks\/?uuid=81f9ddbb-b946-400e-ac10-9afd71c47e32&amp;contributor&amp;keyword&amp;subject=Pharmacy%2FPharmacology\" target=\"_blank\" rel=\"noopener noreferrer\">Medicines by Design<\/a>\u00a0by US Department of Health and Human Services, National Institute of Health, National Institute of General Medical Sciences and is available in the public domain.\u00a0<a class=\"return-footnote\" href=\"https:\/\/wtcs.pressbooks.pub\/pharmacology\/chapter\/1-2-pharmacokinetics\/#return-footnote-190-2\" aria-label=\"Return to footnote 2\">\u21b5<\/a><\/li>\n<\/ol>\n<\/div>\n","protected":false},"author":2,"menu_order":2,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[49],"contributor":[],"license":[],"class_list":["post-25","chapter","type-chapter","status-publish","hentry","chapter-type-numberless"],"part":3,"_links":{"self":[{"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/25","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/wp\/v2\/users\/2"}],"version-history":[{"count":2,"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/25\/revisions"}],"predecessor-version":[{"id":495,"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/25\/revisions\/495"}],"part":[{"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/25\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/wp\/v2\/media?parent=25"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/pressbooks\/v2\/chapter-type?post=25"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/wp\/v2\/contributor?post=25"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-json\/wp\/v2\/license?post=25"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}