Chapter 2 Pharmacologic Principles Copyright © 2017, Elsevier Inc. All rights reserved. Pharmacologic Principles • Drug • Any chemical that affects the physiologic processes of a living organism • Pharmacology • Study or science of drugs Copyright © 2017, Elsevier Inc. All rights reserved. 2 Drug Names Chemical name • Describes the drug’s chemical composition and molecular structure Generic name (nonproprietary name) • Name given by the United States Adopted Names Council Trade name (proprietary name) • The drug has a registered trademark; use of the name is restricted by the drug’s patent owner (usually the manufacturer) Copyright © 2017, Elsevier Inc. All rights reserved. 3 Chemical, Generic, and Trade Names and Chemical Structure of Ibuprofen Copyright © 2017, Elsevier Inc. All rights reserved. 4 Pharmacologic Principles • Pharmaceutics • Pharmacokinetics • Pharmacodynamics • Pharmacogenomics (pharmacogenetics) • Pharmacotherapeutics • Pharmacognosy • Pharmacoeconomics • Toxicology Copyright © 2017, Elsevier Inc. All rights reserved. 5 Pharmaceutics • The study of how various drug forms influence the way in which the drug affects the body • Dissolution-dissolving of solid dosage forms and their absorption Copyright © 2017, Elsevier Inc. All rights reserved. 6 Audience Response System Question A patient is prescribed ibuprofen 200 mg PO every 4 hours as needed for pain. The pharmacy sends up enteric-coated tablets, but the patient refuses the tablets, stating that she cannot swallow pills. What will the nurse do? A. Crush the tablets and mix them with applesauce or pudding. B. Call the pharmacy and ask for the liquid form of the medication. C. Call the pharmacy and ask for the IV form of the medication. D. Encourage the patient to try to swallow the tablets. Copyright © 2017, Elsevier Inc. All rights reserved. 7 Pharmacokinetics • The study of what the body does to the drug • Absorption • Distribution • Metabolism • Excretion IV is fastest way to distribute drugs Copyright © 2017, Elsevier Inc. All rights reserved. 8 Pharmacokinetics (Cont.) • Absorption • Bioavailability • First pass effect • Enteral route • Sublingual buccal routes • Parenteral route: subcutaneous, intradermal, intramuscular • Topical route • Transdermal route • Inhaled route Copyright © 2017, Elsevier Inc. All rights reserved. 9 Enteral Route (GI TRACT) • The drug is absorbed into the systemic circulation through the oral or gastric mucosa or the small intestine • Oral • Sublingual (absorbed fast) • Buccal • Rectal (can also be topical) Copyright © 2017, Elsevier Inc. All rights reserved. 10 Parenteral Route • Intravenous (fastest delivery into the blood circulation) You can give • Intramuscular someone PO and • Subcutaneous IV to quickly get to • Intradermal the pain and then keep it managed • Intraarterial (steady state) • Intrathecal • Intraarticular Copyright © 2017, Elsevier Inc. All rights reserved. 11 Topical Route • Skin (including transdermal patches) • Eyes • Ears • Nose • Lungs (inhalation) • Rectum • Vagina Copyright © 2017, Elsevier Inc. All rights reserved. 12 Audience Response System Question The nurse is preparing to administer a transdermal patch to a patient and finds that the patient already has a medication patch on his right upper chest. What will the nurse do? A. B. C. D. Remove the old medication patch and notify the health care provider. Apply the new patch without removing the old one. Remove the old patch and apply the new patch in the same spot. Remove the old patch and apply the new patch to a different, clean area. Copyright © 2017, Elsevier Inc. All rights reserved. 13 Pharmacokinetics • Distribution • Transport of a drug by the bloodstream to its site of action Copyright © 2017, Elsevier Inc. All rights reserved. 14 Pharmacokinetics (Cont.) • Distribution Copyright © 2017, Elsevier Inc. All rights reserved. 15 Pharmacokinetics (Cont.) • Distribution • Albumin is the most common blood protein and carries the majority of protein-bound drug molecules. Seizure drugs Dilantin Valproic acid Copyright © 2017, Elsevier Inc. All rights reserved. 16 Pharmacokinetics (Cont.) Copyright © 2017, Elsevier Inc. All rights reserved. 17 Pharmacokinetics (Cont.) • Metabolism • Also referred to as biotransformation • Biochemical alteration of a drug into an inactive metabolite, a more soluble compound, a more potent active metabolite (as in the conversion of an inactive prodrug to its active form), or a less active metabolite. Enterocutaneous fistula = hole where one shouldn’t be - meds are not used because they do not get to small intestine 18 Pharmacokinetics (Cont.) • Metabolism (Cont.) • Cytochrome P-450 enzymes (or simply P-450 enzymes), also known as microsomal enzymes • Lipophilic: “fat loving” • Hydrophilic: “water loving” • Enzymes Copyright © 2017, Elsevier Inc. All rights reserved. 19 Pharmacokinetics (Cont.) • Excretion • Elimination of drugs from the body • Renal excretion • Biliary excretion (liver) went through liver and was broken down and processed out through the stool Copyright © 2017, Elsevier Inc. All rights reserved. 20 Pharmacokinetics (Cont.) Copyright © 2017, Elsevier Inc. All rights reserved. 21 Pharmacokinetics (Cont.) • Half-life: time required for half (50%) of a given drug to be removed from `the body • How often a drug is given is important to half life to keep a steady state • Steady state : half life guides steady state • Steady state is important with abx • Kidneys process drugs - BUN (10-20) and creatinine (0.8-1.2) are labs that tell how good kidneys work - If kidney is not working well the drug could build up and become toxic - Nephrotoxic drugs are given due to risks vs benefits • Basic metabolic panel: • BUN • Sodium • Creatine • Glucose • - HYPOTENSION CAN HURT THE KIDNEYS d/t less volume going to the kidney and the nephrotoxic agent can cause more damage • -Mycin abx are very nephrotoxic (RISK OF SEPEIS IS WORSE THAN KIDNEY BEING HURT) • - Contrast dye to determine what injuries a pt has • Copyright © 2017, Elsevier Inc. All rights reserved. 22 Pharmacokinetics (Cont.) • The length of time until the onset and peak of action and the duration of action play an important part in determining the peak level (highest blood level) and trough level (lowest blood level) of a drug. If the peak blood level is too high, then drug toxicity may occur. Copyright © 2017, Elsevier Inc. All rights reserved. 23 Pharmacokinetics (Cont.) • Peak level: highest blood level of a drug • Trough level: lowest blood level of a drug • Toxicity: occurs if the peak blood level of the drug is too high • Therapeutic drug monitoring Copyright © 2017, Elsevier Inc. All rights reserved. 24 Audience Response System Question The nurse is giving a medication that has a high first-pass effect. The health care provider has changed the route from IV to PO. The nurse expects the oral dose to be A. B. C. D. higher because of the first-pass effect. lower because of the first-pass effect. the same as the IV dose. unchanged. Copyright © 2017, Elsevier Inc. All rights reserved. 25 Pharmacodynamics • The study of what the drug does to the body • The mechanism of drug actions in living tissues • Therapeutic effect • Mechanism of action • Drug–receptor relationships • Enzymes Copyright © 2017, Elsevier Inc. All rights reserved. 26 Pharmacodynamics (Cont.) Copyright © 2017, Elsevier Inc. All rights reserved. 27 Audience Response System Question A patient is complaining of severe pain and has orders for morphine sulfate. The nurse knows that the route that would give the slowest pain relief would be which route? A. B. C. D. IV IM Subcutaneous PO Copyright © 2017, Elsevier Inc. All rights reserved. 28 Pharmacotherapeutics • The clinical use of drugs to prevent and treat diseases • Defines principles of drug actions—the cellular processes that change in response to the presence of drug molecules • Drugs are organized into pharmacologic classes Copyright © 2017, Elsevier Inc. All rights reserved. 29 Pharmacotherapeutics (Cont.) • • • • • • • • Contraindications Acute Maintenance (80 ml/hr) Supplemental (or replacement) Palliative – end of life Supportive Prophylactic – preventing Empiric – someone has increase of temp and we want to cover them • Give a bolus to give to counteract kidney destruction Copyright © 2017, Elsevier Inc. All rights reserved. 30 Pharmacotherapeutics (Cont.) • • • • • • • Monitoring Therapeutic action- what we want to happen Adverse effects- diarrhea from abx Toxic effects – abx causing cdiff Therapeutic index Drug concentration – mg/cc Patient condition – is there kidneys + liver working well Copyright © 2017, Elsevier Inc. All rights reserved. 31 Pharmacotherapeutics (Cont.) • Tolerance: decreasing response to repeated drug doses • Dependence: physiologic or psychological need for a drug • Physical dependence: physiologic need for a drug to avoid physical withdrawal symptoms • Psychological dependence: also known as addiction and is the obsessive desire for the euphoric effects of a drug Copyright © 2017, Elsevier Inc. All rights reserved. 32 Pharmacotherapeutics (Cont.) • • • • • Drug interactions Additive effects Synergistic effects Antagonistic effects Incompatibility Copyright © 2017, Elsevier Inc. All rights reserved. 33 Pharmacotherapeutics (Cont.) • Adverse drug event – out come you do not want • Adverse drug withdrawal event – taken away med too quickly • Medication error – reportable event • Adverse drug reaction Copyright © 2017, Elsevier Inc. All rights reserved. 34 Pharmacotherapeutics (Cont.) • Six rights of drug administration • • • • • • Right drug Right dose Right time Right route Right patient Right documentation Copyright © 2017, Elsevier Inc. All rights reserved. 35 Pharmacotherapeutics (Cont.) • • • • • Medication use process Prescribing Dispensing Administering Monitoring Copyright © 2017, Elsevier Inc. All rights reserved. 36 Pharmacotherapeutics (Cont.) • Adverse drug reactions • Pharmacologic reaction • Hypersensitivity (allergic) reaction • Idiosyncratic reaction • Drug interaction Copyright © 2017, Elsevier Inc. All rights reserved. 37 Pharmacotherapeutics (Cont.) • Other drug effects • Teratogenic • Mutagenic • Carcinogenic effects Copyright © 2017, Elsevier Inc. All rights reserved. 38 Pharmacognosy • The study of natural (versus synthetic) drug sources (i.e., plant, animals, minerals) Copyright © 2017, Elsevier Inc. All rights reserved. 39 Pharmacoeconomics • Study of the economic factors influencing the cost of drug therapy • Cost–benefit analysis Copyright © 2017, Elsevier Inc. All rights reserved. 40 Toxicology • Science of the adverse effects of chemicals on living organisms • Clinical toxicology deals specifically with the care of poisoned patients Copyright © 2017, Elsevier Inc. All rights reserved. 41
