Pharmacology and Medication Management Study Notes

Course Overview

  • NURS 1009 Pharmacology & Medication Management Week 1 at Carleton University.

Course Structure

  • Review of syllabus, assignments, and grade breakdown.
  • Overview of professional standards.
  • Chapters covered in this week:
    • Chapter 4: Pharmacokinetics
    • Chapter 5: Pharmacodynamics
    • Chapter 6: Drug Interactions
    • Chapter 7: Adverse Drug Reactions and Medication Errors
    • Chapter 8: Variations in Drug Responses
    • Chapter 11: Drug Therapy During Pregnancy and Breastfeeding
    • Chapter 12: Drug Therapy in Paediatric Patients
    • Chapter 13: Drug Therapy in Older Adults

Safe Medication Practices

  • CNO Foundational Standard: Medication ETP Competency
    • 1.1: Applies knowledge of pharmacology and principles of safe medication practice.

Module Objectives

  • Students will learn to access CNO Foundational Standards, Medication and Documentation.
  • Understanding authority, competence, and safety concerning medication.
  • Documentation skills related to medication.
  • Familiarization with Canadian Patient Safety Institute (CPSI) tools and Institute for Safe Medication Practices (ISMP) resources.

CNO Foundational Practice Standard: Medication

  • Purpose: To outline nurses’ accountabilities in medication practices (administration, dispensing, storage, inventory management, and disposal).
Three Principles of Medication Practices
  • Authority: Nurses must have necessary authority for medication practices.
  • Competence: Nurses must have the knowledge, skill, and judgment to perform medication practices safely.
  • Safety: Compliance with legislation and practice standards is essential for all medications due to potential harm.

Authority

  • Required for:
    • Involvement in controlled acts.
    • Administration of prescription medications.
    • Compliance with legislative requirements.

Competence

  • Nurses must:
    • Seek client medication history.
    • Collaborate with clients to make informed decisions.
    • Provide education on medication use.
    • Ensure practice is evidence-informed.
    • Assess practice appropriateness.
    • Acknowledge personal limits of knowledge.

Safety (continued)

  • Nurses must:
    • Administer via prescriber-indicated routes.
    • Dispense medications directly to clients.
    • Document all medication dispensed.
    • Ensure medications are obtained and stored safely.
    • Report medication errors and adverse reactions.
    • Not engage in practices that conflict with their professional duty.

Additional Support Resources

  • Canadian Patient Safety Institute tools, ISMP resources (e.g., patient safety improvement guides, frameworks for safety culture).

Pharmacokinetics

Definition

  • Pharmacokinetics is the study of drug movement through the body, derived from:
    • Pharmakon (drug or poison)
    • Kinesis (motion)
Four Basic Pharmacokinetic Processes
  • Absorption: Movement from site of administration into the blood.
  • Distribution: Movement from blood to tissues and cells.
  • Metabolism: Enzymatic alteration of drug structure.
  • Excretion: Removal of drugs and metabolites from the body.

Application of Pharmacokinetics to Drug Therapy

  • Maximizing Beneficial Effects: Achieving adequate drug concentrations for desired responses.
  • Minimizing Harm: Avoiding excessive drug concentrations through proper route, dosage, and schedule.

Benefits of Pharmacokinetics in Clinical Practice

  • Reduces medication errors (correct route and dosage).
  • Enhances job satisfaction (less stress regarding drug therapy).

Phases of Pharmacokinetics

  • Absorption: Influenced by drug’s physical/chemical properties and physiological/anatomical factors at the absorption site.

Routes of Administration

  • Enteral: GI tract (e.g., orally - PO).
  • Parenteral: Outside GI tract (e.g., injections: IV, IM, subQ).

Oral Drug Absorption Mechanics

  • Drugs must dissolve before absorption.
  • Larger surface areas (like the small intestine) allow for greater absorption.
  • Drugs with high lipid solubility are absorbed faster.

Drug Distribution

Factors Affecting Distribution
  • Blood Flow: Tissues with high perfusion receive drugs more quickly.
  • Drug Exit from Vascular System: Important for drug action, metabolism, and excretion.
Distribution Mechanisms
  • Capillary Beds: Drugs can pass freely due to pores.
  • Blood-Brain Barrier (BBB): Unique anatomy limits drug passage to the CNS; lipid-soluble drugs cross over more easily.
  • Placenta: Most drugs can cross, but barriers exist for certain types.
  • Protein Binding: Drugs form reversible bonds with proteins which can affect their distribution and efficacy.

Metabolism

Definition
  • Metabolism: Chemical alteration of drug structures primarily in the liver.
  • Enzyme System: Cytochrome P450 family (CYPs) metabolizes drugs into active/inactive forms and alters toxicity.
Therapeutic Consequences of Metabolism
  • Accelerated Renal Excretion: Conversion of lipophilic drugs to hydrophilic forms.
  • Increased Therapeutic Action: Examples include the conversion of codeine to morphine.
  • Increased Toxicity: Certain metabolites can become toxic (e.g., acetaminophen).

Excretion

Definition & Mechanisms
  • Excretion: Removal of drugs from the body (primarily through urine).
  • Renal Processes: Filtration, passive tubular reabsorption, and active secretion.
Non-Renal Excretion
  • Methods include excretion through bile, breast milk, sweat, and respiration.

Time Course of Drug Responses

Key Terms

  • Minimum Effective Concentration (MEC): Plasma drug level required for therapeutic effect.
  • Toxic Concentration: Plasma level at which toxic effects start.

Therapeutic Range

  • Difference between MEC and toxic concentration; the goal of drug dosing is to maintain levels within this range.
Pharmacokinetics Summary
  • Factors such as half-life and multiple dosing impact accumulation, therapeutic effect duration, and drug fluctuation management techniques.

Pharmacodynamics

Definition

  • Pharmacodynamics: Study of drug effects and mechanisms at the biochemical and physiological level.

Dose-Response Relationships

  • Maximal Efficacy: Largest drug effects achievable, which varies between drugs.
  • Potency: Amount of drug required to achieve an effect; independent of efficacy.
Receptor Interactions
  • Drugs interact with receptors to produce effects (active vs. inactive states).

Drug Interactions and Adverse Reactions

Overview

  • Drug interactions can enhance or inhibit drug efficacy/safety and can have intended or unintended consequences.

Common Drug Interaction Mechanisms

  • Direct Chemical Interaction: Inactive combinations.
  • Altered Absorption: Changes in absorption due to other drugs.
  • Altered Metabolism: Changes in metabolic pathways impacting drug effect.

Medication Errors

Definition

  • Medication Errors: Preventable events leading to inappropriate medication use or patient harm.

Prevention Strategies

  • Encouraging a culture of safety, education for healthcare professionals, and ensuring proper communication during prescribing and administration.
Key Takeaway
  • Understanding pharmacokinetics and pharmacodynamics, along with safe medication practices, is vital for effective nursing care, particularly for vulnerable populations like infants, the elderly, and pregnant patients.