1. Pharmacologic Principles
Chapter 2
Pharmacologic Principles
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2. Pharmacologic Principles
Drug
Any chemical that affects the physiologic processes of a living organism
Pharmacology
Study or science of drugs
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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)
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4. Chemical, Generic, and Trade Names and Chemical Structure of Ibuprofen
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5. Pharmacologic Principles
Pharmaceutics
Pharmacokinetics
Pharmacodynamics
Pharmacogenomics (pharmacogenetics)
Pharmacotherapeutics
Pharmacognosy
Pharmacoeconomics
Toxicology
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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
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7. 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.
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Pharmacokinetics
The study of what the body does to the drug
Absorption
Distribution
Metabolism
Excretion
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9. Pharmacokinetics (Cont.)
Absorption
Bioavailability
First pass effect
Enteral route
Sublingual buccal routes
Parenteral route: subcutaneous, intradermal, intramuscular
Topical route
Transdermal route
Inhaled route
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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)
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Parenteral Route
Intravenous (fastest delivery into the blood circulation)
Intramuscular
Subcutaneous
Intradermal
Intraarterial
Intrathecal
Intraarticular
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Topical Route
Skin (including transdermal patches)
Eyes
Ears
Nose
Lungs (inhalation)
Rectum
Vagina
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13. 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.
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Pharmacokinetics
Distribution
Transport of a drug by the bloodstream to its site of action
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15. Pharmacokinetics (Cont.)
Distribution
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16. Pharmacokinetics (Cont.)
Distribution
Albumin is the most common blood protein and carries the majority of protein-bound drug molecules.
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17. Pharmacokinetics (Cont.)
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18. 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.
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19. 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
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20. Pharmacokinetics (Cont.)
Excretion
Elimination of drugs from the body
Renal excretion
Biliary excretion
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21. Pharmacokinetics (Cont.)
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22. Pharmacokinetics (Cont.)
Half-life: time required for half (50%) of a given drug to be removed from the body
Steady state
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23. 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.
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24. 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
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25. 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.
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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
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27. Pharmacodynamics (Cont.)
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28. 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.
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29. 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
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30. Pharmacotherapeutics (Cont.)
Contraindications
Acute
Maintenance
Supplemental (or replacement)
Palliative
Supportive
Prophylactic
Empiric
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31. Pharmacotherapeutics (Cont.)
Monitoring
Therapeutic action
Adverse effects
Toxic effects
Therapeutic index
Drug concentration
Patient condition
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32. 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
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33. Pharmacotherapeutics (Cont.)
Drug interactions
Additive effects
Synergistic effects
Antagonistic effects
Incompatibility
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34. Pharmacotherapeutics (Cont.)
Adverse drug event
Adverse drug withdrawal event
Medication error
Adverse drug reaction
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35. Pharmacotherapeutics (Cont.)
Six rights of drug administration
Right drug
Right dose
Right time
Right route
Right patient
Right documentation
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36. Pharmacotherapeutics (Cont.)
Medication use process
Prescribing
Dispensing
Administering
Monitoring
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37. Pharmacotherapeutics (Cont.)
Adverse drug reactions
Pharmacologic reaction
Hypersensitivity (allergic) reaction
Idiosyncratic reaction
Drug interaction
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38. Pharmacotherapeutics (Cont.)
Other drug effects
Teratogenic
Mutagenic
Carcinogenic effects
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Pharmacognosy
The study of natural (versus synthetic) drug sources (i.e., plant, animals, minerals)
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Pharmacoeconomics
Study of the economic factors influencing the cost of drug therapy
Cost–benefit analysis
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Toxicology
Science of the adverse effects of chemicals on living organisms
Clinical toxicology deals specifically with the care of poisoned patients
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