Nursing Pharmacology Basics

Basic Pharmacology Terms

• Pharmacology Defined: The study of drugs/medications and their action on the living body.
  • A science concerned with the history, sources, physical & chemical properties of drugs, and their effects on living systems.
• Drug/Medicine Defined: Any chemical substance that affects living systems by changing their structure or function.

Subdivisions of Pharmacology

• Pharmacodynamics: Study of the biochemical and physiological effects of drugs and their mechanisms of action.
• Pharmacokinetics: Study of the:
  • Absorption of a drug from the site of entry to circulation.
  • Distribution, biotransformation (metabolism), and excretion (elimination) of the drug from the body.
• Chronopharmacology: Study of the relationship between the time of drug administration and the drug's effect.
• Pharmacotherapeutics: Study of how drugs can best be used to treat diseases.
  • Specifies what diseases a drug treats and appropriate dosages.
• Phytochemistry: Study of drugs derived from herbs and other natural sources.
  • Historically, all drugs came from plants; most are now synthetically produced.
• Toxicology: Study of poisons and poisoning.

History of Pharmacology

• Early Views: Disease was viewed as mystical, leading to superstitions and experimentation with plants.
  • Examples: alcohol and opium.
• Ancient Egypt: Credited as the cradle of pharmacology.
  • Ebers Papyrus: First written medical information (over 3,000 years ago) containing 700+ remedies.
• Hippocrates (4th Century BC): First human dissection to study organs and diseases.
• Dioscorides: Scientifically described and classified 600 plants in "De Materia Medica".
  • A major source of pharmaceutical knowledge up to the 16th century.
• Paracelsus (16th Century):
  • Advocated for single-drug use instead of mixtures.
  • Recognized the dangers of too much or too little of a drug.
  • Noted that all drugs are poisons and dosage determines toxicity.
  • Known as the father of pharmacology.
• William Harvey (17th Century): Credited with discovering blood circulation.
• Joseph Lister (19th Century): Credited with using antiseptics in surgery to prevent infection.
• Alexander Fleming: Discovered penicillin in 1928.
• Frederick Banting and Charles Best: Discovered insulin in the 1930s.

Sources of Drugs

• Substances derived from plants, animals, vitamins, minerals, and synthetic/artificial sources can all be drugs.
• Natural Sources:
  • Animals:
    • Insulin: Obtained from the pancreas of beef and pork.
    • Heparin: Obtained from the intestinal mucosa of beef and pork.
  • Plants:
    • Digoxin: Comes from foxglove.
    • Chemotherapy treatments: Derived from the yew tree.
    • Kaopectate: Comes from clay.
    • Metamucil: Comes from psyllium.
• Semisynthetic Drugs: Drugs from natural sources that have been chemically altered.
  • Example: Animal insulin modified to match human insulin.
• Synthetic Drugs: Made from chemical reactions in a lab.
  • Characteristics: very pure and free from impurities.
  • Examples: hydrochloride and Synthroid.
  • Most modern drugs are synthetic.
• Biotechnology: Involves genetic engineering and gene splicing.
  • Gene splicing: Insertion of a gene portion from one species' chromosome into another's gene.
    • Allows alteration of a gene to function in a new context.
    • Example: apple tree limb attached to a peach tree.
  • Inoculated bacteria: Example: Humulin (human insulin).
  • Another Example: hepatitis B vaccine.

Drug Uses

• Symptomatic Treatment: Relieves or decreases disease symptoms.
  • Example: acetaminophen (Tylenol) to reduce fever.
• Preventative Drugs: Used to stop a disease.
  • Example: Vaccines, such as the hepatitis B vaccine.
• Diagnostic: Lets us know if a disease is present.
  • Example: Radio dyes used in x-rays.
• Curative: Eliminates a disease.
  • Example: Antibiotics.
• Health Maintenance: Helps the body function normally.
  • Examples: Vitamins and insulin.
• Contraceptives: Prevent pregnancy.
  • Examples: birth control pills and implants.

Forms of Drugs

• Internal Medications: Absorbed within the GI tract, usually given orally.

  • Powders: Mixed with liquid before administration.

  • Pills: Round solid drug form that must be broken down into a solution in the stomach.

  • Tablets: Round, spherical, or shaped forms that dissolve in the stomach; very popular and easiest to give.

    • Scored: Indentation allows the tablet to be broken in half.

  • Enteric-Coated Tablets: Coated shell prevents absorption in the stomach; absorption occurs in the intestines.

    • Used for medications irritating to the stomach or destroyed by stomach acid.
    • Should not be given with milk or acids; pH affects absorption.
    • Should not be crushed or chewed.

  • Time-Sustained, Delayed, or Extended-Release Drugs: Coated with materials that dissolve at varying times.

  • Capsules: Powders or pellets enclosed in a gelatin-like form.

    • Encapsulated due to bad taste or for timing reasons.
    • Do not open or crush.
    • Hard shell or soft shell (often with liquid inside).

  • Lozenges: Sweet tablets that dissolve in the mouth to release medication (cough drops).

  • Sublingual/Buccal Tablets: Given under the tongue or inside the cheek and dissolve in the mouth.

    • Enters directly into circulation; bypasses the stomach.
    • No food or fluid until fully absorbed.

  • Oral Medications:

    • Liquids and Suspensions: Solid particles separate; shake well before administration.

      • Often contain flavor and color (easier for pediatric patients).
      • Shake suspensions thoroughly.

  • Suppositories: Drugs mixed with a lubricating substance and molded for insertion into the body.

    • Given rectally, vaginally, or urethrally.
    • Absorption occurs when the suppository melts or dissolves with body fluids.

• Percutaneous Medications: Absorbed through the skin or mucous membranes.

  • Usually produces a local action, but some can be systemic.

  • Typically, rapid absorption.

  • Topical Applications: Lotions, ointments, creams, patches.

    • Lotions: Water-based preparations that relieve pruritus (itchy skin) or protect/cleanse the skin.
    • Ointments: Oil-based semisolid medications applied to the skin or mucous membranes (e.g., nitroglycerin ointments).
    • Creams: Semi-solid non-greasy emulsions for external application.
    • Transdermal Patches: Adhesive patches providing sustained release over hours or days (e.g., nitroglycerin patches, nicotine patches).

  • Eye Drops (Ophthalmic): Drops or ointments at room temperature.

  • Eye Irrigation: Washing an area with a stream of solution through a syringe.

    • Go from the inner to the outer part of the eye.
    • Relieves inflammation, applies antiseptic solution, or flushes out exudate/irritating solutions.

  • Compresses: Warm, moist cloths to reduce inflammation (e.g., eye compresses).

  • Ear Drops (Otic): Administer at room temperature.

  • Nasal Sprays/Irrigations: Quickly absorbed through mucous membranes; less medication is needed.

• Parenteral Medications: Routes other than the digestive system, given with a syringe and needle.

  • Ampules: Glass containers accessed by snapping off the top.

    • Single-dose; use a filter needle to prevent glass from entering the syringe.

  • Vials: Glass containers sealed with a metal cap and rubber diaphragm.

    • Can be single-dose or multi-dose.
    • Larger amounts in glass or plastic containers for IVs.

  • Pre-filled Syringes: Single-dose methods used one time only.

Sources of Information

• Healthcare professionals need a reliable resource for drug information due to constant changes and new drugs.

• Institution Drug Formulary: List of drugs used at a specific institution.

  • Example: Specific list of drugs used in chemotherapy.

• American Hospital Formulary Service: Published by the American Society of Hospital Pharmacists.

  • Published annually with quarterly updates.
  • Provides information about all drugs currently in use in the United States.
  • Often called the "big red book."

• American Drug Index: Complete and current listing of drugs and drug products in a single source.

  • Published annually.
  • Provides basic drug information (brand & generic names, dose, form).
  • Little pharmacology information beyond that.

• Physician's Desk Reference: Annual publication, color-coded.

  • Drugs listed by brand and generic name with color photos for identification.
  • Doesn't include specific nursing implications.

• Nurses' Drug Handbooks/Guides: Contain all drug information and nursing implications.

  • Like the Physician's Desk Reference but for nurses.
  • Specifically has nursing considerations.

• Package Insert: Detailed description of the drug included in the package of all legend drug products sold in the United States.

  • Includes the brand name, generic name, description, clinical pharmacology, indications/usages, contraindications, warnings, precautions, what to do in case of an overdose, dosage and administration rules, how it is supplied, and the date it was published.
  • Helpful for information, such as vaccine strains for flu vaccines.

Drug Cards

• Drug cards will need to be handwritten.
• Use a credible source (drug guide or reliable internet source, not Wikipedia, Google, or WebMD).
• Complete drug cards for each system covered in class.
• Two drug cards for each drug class (can put two drugs on one card if in the same class).
• Include the following information:
  • Name of the drug (brand and generic).
  • Circle class of drug and system it belongs to.
  • Classification: How the drug works (what part of the body it affects and what it does).
  • Therapeutic uses: Why the drug is used (what it treats).
  • Side effects: Common and life-threatening.
  • Nursing considerations: What to be aware of before, during, and after administration (labs, vital signs, etc.).
  • Contraindications: Who shouldn't take the drug or use with caution.
  • Patient education: What else the patient needs to know (time of day to take, avoid sun, etc.).
  • Route and dosage: Typical adult dosage (common routes and dosages).