2047 L1

NUR2047 Pharmacology

• Focuses on basic drug concepts and dosage calculations.
• Course is taught by Winsy WAN.

Basic Concept

• Drug Names:

  • Chemical names describe drug structures based on atomic/molecular structure and functional groups. Used less in medical practice.
  • Generic names assigned by manufacturers (approved by regulatory bodies). Used throughout a drug's lifetime and recognized internationally.
  • Brand names/trade names are usually short and easy to remember. One drug can have multiple brand names from different companies.

• Drug Effects:

  • Therapeutic effect is the desired effect of a drug.
  • Palliative drug relieves disease symptoms without affecting the disease itself.
  • Curative drug cures a disease or condition.
  • Supportive drug supports body function until other treatments are available or the body's response picks up.
  • Substitutive drug replaces body fluids or substances.
  • Chemotherapeutic drug destroys malignant cells.
  • Restorative drug returns the body to health.
  • Side effects are unintended but predictable responses. Can range from mild to severe.
  • Adverse drug reactions are harmful and undesirable responses that can range in severity from mild to severe.
  • Secondary effects are additional effects of a drug, which can be either beneficial or harmful.

• Drug Interactions:

  • Drug interactions can occur between drugs or between drugs and food.
  • Multiple drugs increase the chance of interaction
  • Interactions can be beneficial or harmful.
  • Food interactions can altar drug absorption, bio-availability, and rate.

• Drug Toxicity:

  • Augmented reactions/drug toxicity are potentially harmful effects resulting from altered pharmacokinetics (absorption, metabolism, excretion).
  • Increased receptor sensitivity can increase a patient's response to drugs and adverse effects or impaired metabolism or excretion.
  • Cumulative effect occurs when the administration rate of a drug exceeds the metabolism or excretion rate causing an accumulation of drug in the blood.
  • Overdose is an excessive dosage, intentionally or accidentally given. It can also be caused by medical or drug therapy or negligence.

Drug Allergy

• Hypersensitivity is an abnormal response to a drug resulting from an immunologic reaction.
• When exposed to a foreign substance (antigen), the body may produce antibodies, developing mild allergic reactions, or severe anaphylactic reactions.
• Symptoms can occur anytime from a few minutes to two weeks after the administration of the drug. Important to ask about the allergy history as well as related signs and symptoms.
• Mild reactions might include skin rash, itching, angioedema, diarrhea, vomiting, rhinitis, or swelling.
• Severe reactions can be life-threatening and fatal including wheezing and dyspnea, accumulated fluids in the respiratory tissue, acute shortness of breath, acute hypotension, and tachycardia.

Drug Effects - Adverse Reactions

• Idiosyncratic effect is a sensitivity-related adverse reaction not due to drug's pharmacological properties or allergies. It is unexpected and unexplained reaction to a drug for a given patient.
• Some reactions have a genetic cause.
• Examples include Stevens-Johnson Syndrome.

Drug Effects - Dependence

• Physiological dependence is due to biochemical changes in the body tissues, especially in the nervous system. Tissues begin to require the substance for normal functioning.
• Psychological dependence is an emotional reliance on a drug to maintain a sense of well-being, accompanied by feelings or cravings for that drug.
• Drug habituation is a mild form of psychological dependence.

Drug Effects - loss of drug effect

• Drug tolerance is a decreased response to a drug over time.
• Tachyphylaxis refers to a rapid decrease in the effectiveness of a drug over a short time.
• Drug resistance is when a drug has a decreased or no effect, such as with antibiotics.

Dosage Calculation

• Understand metric units of weight and volume.
• Understand how to convert between units.
• Methods to calculate dosages by using the universal formula, ratio proportions.

Pharmaco-kinetics

• Study of what the body does to the drug.
• The processes of absorption, distribution, metabolism, and excretion.

Pharmaco-dynamics

• Study of what the drug does to the body.
• The mechanisms by which drugs exert biochemical and physiological effects at their target sites.

Pharmaco-kinetics vs Pharmaco-dynamics

• Pharmacokinetics are the body's interactions with the drug; and Pharmacodynamics describes drug effect on an organism.

ADME

• Absorption, distribution, metabolism, excretion describe the processes of a drug in the human body

Drug Formulation & Route

• Several methods used to administer drugs.

Types of Drug Preparations

• Descriptions and details provided for different types of drug preparations.

Drug Administration

• Routes of administration and their relevant pros and cons of drug administration
  • Oral dosage
  • Intravenous dosage
  • Intramuscular dosage
  • Subcutaneous dosage
  • Buccal dosage
  • Sublingual dosage
  • Rectal dosage
  • Inhalation dosage
  • Topical dosage
  • Transdermal dosage

Drug Absorption

• Oral (PO): Rate of absorption can be affected by food, acid medium, and the fact that some drugs don't dissolve well in GI fluids.
• Intravenous (IV): Direct entry to the bloodstream.
• Intramuscular (IM): Rapid, but more prone to risk if high bleeding.
• Subcutaneous (SC): Slower absorption than intramuscular.
• Rectal: Absorption can be unpredictable/used for localized needs only when other means are not available.

ADME - Distribution

• Transportation of a drug from absorption site to its site of action in the body.
• Blood flow is a major factor, affecting drug delivery to different organs based on vascularity.
• Solubility is another significant factor, impacting either drug accumulation in fatty tissue or binding to plasma proteins.

ADME - Metabolism

• Biotransformation: drugs chemically altered by the body.

• Conversion of prodrugs into active drugs by enzymes.

• Metabolic processes impact drug activity and toxicity, potentially leading to further metabolism of the metabolites.

• Drugs can undergo further metabolism before excretion.

• Understand what CYP450 enzymes are responsible for during the metabolic processes.

• Factors effecting metabolism (Chemical, Biological, Physiochemical)

ADME- Excretion

• Removal of drugs from the body.
• Primarily through the kidneys, but can also involve bile, sweat, breast milk, and lungs.
• Changes in excretion rate impact plasma drug concentration.

Other forms of excretion

• Excretion pathways aside from via the kidneys including through bile, sweat, and breast milk
• The lungs can excrete drugs, as well as exocrine glands (sweat, salivary, or mammary)

Dosage Calculation (Advanced) - Includes Body Weight

• Dosage calculations are crucial for effective and safe drug administration, especially considering patient-specific factors.

Loading Dose and Maintenance Dose

• Loading dose is given at the outset of therapy to quickly achieve the target concentration
• Maintenance dose adapts drug dosage to keep the level at a steady state and avoid overdose.

Basic Concepts of Pharmacodynamics

• Drug's effects on an organism and receptor/ non-receptor mechanisms.
• Agonists (promote response by binding to receptor) and antagonists (prevent response or block)
• Understanding different types of receptors(internal and cell surface) including the role of these receptors and G protein couples including the role of enzymes in these processes