venipuncture

• Four goals of pharmacology:

  • Gain knowledge of various drug types
  • Describe forms in which medications are administered
  • Describe proper modes of administration
  • Recognize toxicity and overdose
• • Animal insulin and penicillin changed the treatment of endocrine and infectious diseases in the 20th century
  • Presently, human insulin and tPA (Tissue plasminogen activator) are used
• Historical Trends in Pharmacology:

  • Ancient health care used herbs and minerals to treat the sick and injured as far back as 2000 B.C.
  • Tinctures of opium, coca, and digitalis were available in the 17th and 18th centuries
  • In 1796, Edward Jenner developed smallpox inoculation
  • In 1875, Rudolf Steiner demonstrated that chickenpox was caused by an infectious agent
  • In 1954, Thomas Weller isolated VZV from vesicular fluid
  • Atropine, chloroform, codeine, ether, and morphine were in use in the 19th century
• Routes of Drug Administration:

  • Enteral Route:
  • Involves the esophagus, stomach, and intestines
  • Includes Oral and Sublingual administration
  • Parenteral Route:
  • Involves intravenous, intramuscular, and subcutaneous administration
  • Other Routes:
  • Include Inhalation, Intrathecal/Intraventricular, Topical, Transdermal, and Rectal administration
• Six Rights of Medication Administration:

  • Right patient
  • Right Medication
  • Right Dose
  • Right Time
  • Right Route
  • Right Documentation
• Special Considerations:

  • Pregnant Patients:
  • Consider benefits vs. risks to the fetus
  • FDA categories indicate drug safety during pregnancy
  • Pediatric Patients:
  • Dosage based on weight or body surface area
  • Broselow Tape used for pediatric emergencies
  • Geriatric Patients:
  • Physiological changes affect drug response
  • Polydrug use is common
• Pharmacokinetics (ADME):

  • Absorption
  • Distribution
  • Metabolism
  • Elimination
  • Determines speed, intensity, and duration of drug action
• Mechanism of Drug Absorption from GI Tract:

  • Passive diffusion
  • Facilitated diffusion
  • Active transport
  • Endocytosis and Exocytosis
  • Variables affecting drug absorption include nature of absorbing surface, blood flow, solubility, pH, drug concentration, dosage form, routes of administration, and bioavailability
• Passive Transport:

  • Diffusion: Movement of solute from high to low concentration
  • Osmosis: Movement of solvent from low solute concentration to high solute concentration
  • Filtration: Movement of molecules from high pressure to low pressure
• Active Transport:

  • Involves specific carrier proteins
  • Requires energy
  • Moves drugs against the concentration gradient
  • Selective and saturable
  • Example: Na - K pump
• Endocytosis and Exocytosis:

  • Endocytosis: Engulfment of a molecule by the cell membrane
  • Exocytosis: Release of molecules
  • Example: Vitamin B12 transport across the gut wall by endocytosis
• Distribution:

  • Reversible process where the drug leaves the bloodstream and distributes into interstitial and intracellular fluids
  • Transport of a drug through the bloodstream to various tissues and its site of action
  • Includes drug reservoirs and plasma protein binding (e.g., Albumin)
• Barriers to Drug Distribution:

  • Some organs exclude drugs from distribution
  • Blood brain barrier: Tight junction of capillary endothelial cells in the CNS vasculature
  • Placental barrier: Restricts certain molecules at the maternal/fetal interface
• Metabolism:

  • Biotransformation of drugs into metabolites by the liver or other tissues
  • Majority occurs in the liver (endoplasmic reticulum)
  • Effects of biotransformation: Can make a drug more or less active, or more water soluble
• Elimination:

  • Drugs and metabolites are eliminated into urine, bile, or feces
  • Organs of excretion include kidneys, intestines, lungs, sweat and salivary glands, and mammary glands
• Pharmacodynamics:

  • Study of a drug's effects
  • Types of drug actions: Receptor interaction, changing cell properties, chemical combination, altering metabolic pathways
• Drug Response Relationship:

  • Optimal effects require appropriate drug concentrations at the site of action
  • Response depends on dosage and drug's course through the body
  • Therapeutic index and biological half-life are important factors
• Factors Altering Drug Response:

  • Age, body mass, sex, environmental milieu, time of administration, pathologic state, genetic factors, psychological factors