Pharmacology Chapter 2 Flashcards

Pharmacology Overview

• Pharmacology is the scientific study of drugs and their effects on living organisms.
• A drug is any chemical that alters physiological processes in the body.

Drug Nomenclature

• Chemical Name: Describes a drug's molecular structure.
• Generic Name: Official name approved by Health Canada under regulations.
• Trade Name: Registered trademark assigned by the manufacturer for a drug product.

Key Concepts in Pharmaceutics

• Pharmaceutics studies how dosage forms affect pharmacokinetics (drug movement in the body) and pharmacodynamics (drug effects on the body).
• Drug absorption involves crossing bodily surfaces into circulation; factors affecting absorption include gastrointestinal (GI) tract status and drug form.

Pharmacokinetics Processes

• Four basic processes: Absorption, Distribution, Metabolism, Excretion.
• Absorption: Drugs enter systemic circulation from administration site.
• Distribution: Absorbed drugs are transported to action sites via blood and lymph.
• Metabolism: Primarily occurs in the liver where drugs are converted to less active forms.
• Excretion: Drugs are eliminated from the body, mostly through the kidneys.

Drug Absorption and Administration Routes

• Bioavailability indicates the extent and rate of drug absorption.
• Oral route undergoes the first-pass effect, where the liver metabolizes drugs before they reach systemic circulation.
• Parenteral routes (IV, IM, SC) bypass the first-pass effect.
• Topical and inhalation routes allow for gradual absorption and longer action duration.

Distribution Patterns

• Rapid distribution to vital organs: heart, liver, kidneys, brain.
• Slow distribution to muscle, skin, fat.
• CNS drugs must be lipid-soluble or injected directly into cerebrospinal fluid due to the blood-brain barrier.

Drug Effects and Dynamics

• Therapeutic effect is the desired positive change in a faulty physiological system.
• Mechanisms of action include drug-receptor interactions and drug-enzyme interactions.
• Affinity refers to how strongly a drug binds to its receptor.

Drug Interactions and Effects

• Drug interactions alter the pharmacological effects and can be additive, synergistic, antagonistic, or show incompatibility.
• Adverse drug reactions (ADRs) can arise from predictable effects, hypersensitivity, and idiosyncratic responses.

Special Considerations

• Teratogenic effects refer to drug-induced fetal abnormalities; pregnant women should avoid most drugs.
• The liver is the primary organ for drug metabolism while the kidneys are vital for drug excretion.

Dosage and Administration

• Half-life is the time taken for half of the drug to be eliminated from the body, generally taking about five half-lives for full clearance.
• Steady state occurs when drug elimination equals the dose administered.

Therapeutic Index and Tolerance

• The therapeutic index measures the margin between effective and toxic drug doses.
• Tolerance is the diminishing effect experienced with repeated doses.

Sources and Evidence in Pharmacology

• Drugs can be derived from animals, plants, minerals, and lab synthesis.
• Evidence-informed practice leads to better clinical outcomes through effective interventions.