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Overview of Pharmacology Key Concepts

Apr 23, 2025

Pharmacology Lecture Notes

Chapter 21: Introduction to Pharmacology

Objectives

  • Recognize common definitions and nomenclature associated with pharmacology.
  • Recognize the various classifications of drugs.
  • Describe the actions, indications, and precautions related to various drugs.

Key Concepts in Pharmacology

  • Drug Definition: A chemical substance that produces a biologic response in a living system.
  • Intent of Drugs: Aid in diagnosis, treatment, or prevention of disease.
  • Pharmacology: Science concerned with the origin, nature, effects, and uses of drugs.

Drug Nomenclature

  • Chemical Name
    • Identifies the chemical structure of a drug (e.g., Acetylsalicylic Acid).
  • Generic Name
    • Name given when a drug becomes commercially available (e.g., Aspirin).
  • Trade Name
    • Name given by a particular manufacturer (e.g., Bayer Aspirin).

Physician's Desk Reference (PDR)

  • Commonly known as PDR.
  • Annual publication with current product information.
  • Available online and in hardbound format.
  • Contains accepted uses, side effects, contraindications, biochemical action, drug class, and dosage considerations for FDA-approved drugs.
  • Consult a pharmacist if PDR is unavailable.

Drug Classifications and Dosages

  • Classification by Chemical Action: Drug Families.
  • Classification by Legal Name
    • Legend Drugs: Prescription drugs.
    • Non-Prescription: Over-the-counter drugs.
  • Dosage Forms
    • Tablets, Inhalants, Suppositories, Capsules, Solutions, Suspensions, Transdermal Patches, Creams.

Classification by Drug Action

  1. Analgesics: Pain relievers.
  2. Anesthetics: Induce anesthesia.
  3. Anti-anemic Agents
  4. Anti-anxiety Agents
  5. Anti-arrhythmics
  6. Antibiotics
  7. Anticholinergics
  8. Anticoagulants
  9. Antidepressants
  10. Antiepileptics

Additional Drug Action Classifications

  • Antidiabetic Agents
  • Antiemetics
  • Antifungal Agents
  • Antihistamines
  • Antihyperlipidemic Agents
  • Antihypertensives
  • Antiparkinson Agents
  • Antiplatelets
  • Antipsychotics

Further Drug Action Classifications

  • Antiallergic Agents
  • Antiviral Agents
  • Benzodiazepine Antagonists
  • Bronchodilators
  • Cholinesterase Inhibitors
  • Coagulants
  • Corticosteroids
  • Diuretics
  • Hormones
  • Laxatives
  • Hypnotics

Final Drug Action Classifications

  • Anti-Alzheimer's Drugs
  • Mood Stabilizing Drugs
  • Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
  • Opioid Antagonist
  • Osteoporosis Drugs
  • Sedatives
  • Stimulants
  • Thrombolytics
  • Vasoconstrictors
  • Vasodilators

Controlled Drug Schedules

  • Regulated by the Federal Controlled Substances Act.
  • Consists of 5 schedules.
  • Indicates drug action and its likelihood of abuse and physical/psychological dependency.

Pharmacokinetics Process

  • Absorption
  • Distribution
  • Metabolism
  • Excretion

Drug Absorption

  • How drug enters the circulatory system.
  • Bioavailability: Amount of drug that reaches systemic circulation.
  • Drugs need to be absorbed to begin activity.

Drug Distribution

  • Absorption of drug into the body and its travel to the intended site of activity via the circulatory system.
  • Affected by several factors.

Drug Metabolism (Biotransformation)

  • Altering the drug's chemical structure.
  • Mostly occurs in the liver.
  • Affected by many factors, including drug interactions.

Drug Excretion

  • Primary Route: Kidneys.
  • Secondary Routes: Liver and biliary tract, lungs, sweat, saliva, breast milk.

Factors Influencing Drug Action

  • Patient Age.
  • Health Status.
  • Time of Day.
  • Emotional State.
  • Other Drugs in the Body.
  • Genetic Variations.
  • Disease State.

Drug Reactions

  • Side Effect: Unrelated response due to drug acting on non-target tissues.
  • Idiosyncratic Reaction: Uncommon response not including therapeutic effect.
  • Anaphylaxis: Severe reaction causing respiratory/cardiovascular collapse.

Sedation Drugs

  • Minimal Sedation/Anxiolysis
  • Moderate Sedation/Analgesia (Conscious Sedation)
    • Common in select medical imaging procedures.
  • Deep Sedation/Analgesia
  • General Anesthesia

Conclusion

  • Radiologic and imaging science professionals need a basic knowledge of pharmacology.
  • PDR is a key reference found in radiology departments.
  • Pharmacists should be consulted for drug-related queries.
  • Common dosage forms include tablets, capsules, suppositories, solutions, suspensions, and transdermal patches.
  • Professionals should be aware of drug actions, precautions, and the factors affecting patient response.
  • Post-administration, relevant drug information should be recorded in the patient's chart.