Pharmacologic Principles 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.

Copyright © 2017, Elsevier Inc. All rights reserved. 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.

Chemical, Generic, and Trade Names and Chemical Structure of Ibuprofen Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacologic Principles Pharmaceutics Pharmacokinetics Pharmacodynamics Pharmacogenomics (pharmacogenetics) Pharmacotherapeutics Pharmacognosy Pharmacoeconomics Toxicology Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. 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.

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? Crush the tablets and mix them with applesauce or pudding. Call the pharmacy and ask for the liquid form of the medication. Call the pharmacy and ask for the IV form of the medication. Encourage the patient to try to swallow the tablets. Correct answer: B Rationale: The liquid form is appropriate because it is also given via the oral route. Enteric-coated tablets should not be crushed, and the patient should not be forced to take the tablets. This medication does not have an IV form, but even if it did, the routes cannot be changed without a health care provider’s order. Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. Pharmacokinetics The study of what the body does to the drug Absorption Distribution Metabolism Excretion Copyright © 2017, Elsevier Inc. All rights reserved.

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.

Copyright © 2017, Elsevier Inc. All rights reserved. Enteral Route The drug is absorbed into the systemic circulation through the oral or gastric mucosa or the small intestine Oral Sublingual Buccal Rectal (can also be topical) Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. Parenteral Route Intravenous (fastest delivery into the blood circulation) Intramuscular Subcutaneous Intradermal Intraarterial Intrathecal Intraarticular Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. Topical Route Skin (including transdermal patches) Eyes Ears Nose Lungs (inhalation) Rectum Vagina Copyright © 2017, Elsevier Inc. All rights reserved.

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? 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. Correct answer: D Rationale: Transdermal drugs should be placed on alternating sites, on a clean and nonirritating area, and only after the previously applied patch has been removed. Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. Pharmacokinetics Distribution Transport of a drug by the bloodstream to its site of action Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacokinetics (Cont.) Distribution Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacokinetics (Cont.) Distribution Albumin is the most common blood protein and carries the majority of protein-bound drug molecules. Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacokinetics (Cont.) Copyright © 2017, Elsevier Inc. All rights reserved.

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. Copyright © 2017, Elsevier Inc. All rights reserved.

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.

Pharmacokinetics (Cont.) Excretion Elimination of drugs from the body Renal excretion Biliary excretion Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacokinetics (Cont.) Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacokinetics (Cont.) Half-life: time required for half (50%) of a given drug to be removed from the body Steady state Copyright © 2017, Elsevier Inc. All rights reserved.

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.

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.

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 higher because of the first-pass effect. lower because of the first-pass effect. the same as the IV dose. unchanged. Correct answer: A Rationale: The first-pass effect is the metabolism of a drug before it becomes systemically available, and it reduces the bioavailability of the drug. Therefore, oral doses need to be higher than IV doses because of the first-pass effect. Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. 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.

Pharmacodynamics (Cont.) Copyright © 2017, Elsevier Inc. All rights reserved.

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? IV IM Subcutaneous PO Correct answer: D Rationale: Parenteral routes result in the fastest absorption and therefore also the fastest effects. Copyright © 2017, Elsevier Inc. All rights reserved.

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.

Pharmacotherapeutics (Cont.) Contraindications Acute Maintenance Supplemental (or replacement) Palliative Supportive Prophylactic Empiric Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacotherapeutics (Cont.) Monitoring Therapeutic action Adverse effects Toxic effects Therapeutic index Drug concentration Patient condition Copyright © 2017, Elsevier Inc. All rights reserved.

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.

Pharmacotherapeutics (Cont.) Drug interactions Additive effects Synergistic effects Antagonistic effects Incompatibility Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacotherapeutics (Cont.) Adverse drug event Adverse drug withdrawal event Medication error Adverse drug reaction Copyright © 2017, Elsevier Inc. All rights reserved.

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.

Pharmacotherapeutics (Cont.) Medication use process Prescribing Dispensing Administering Monitoring Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacotherapeutics (Cont.) Adverse drug reactions Pharmacologic reaction Hypersensitivity (allergic) reaction Idiosyncratic reaction Drug interaction Copyright © 2017, Elsevier Inc. All rights reserved.

Pharmacotherapeutics (Cont.) Other drug effects Teratogenic Mutagenic Carcinogenic effects Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. Pharmacognosy The study of natural (versus synthetic) drug sources (i.e., plant, animals, minerals) Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. Pharmacoeconomics Study of the economic factors influencing the cost of drug therapy Cost–benefit analysis Copyright © 2017, Elsevier Inc. All rights reserved.

Copyright © 2017, Elsevier Inc. All rights reserved. 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.