Pharmacology Exam 1 Study Guide

Study Notes

Pharmacology Exam 1 Study Guide

Pharmacokinetics: The process of drug movement in the body to achieve drug action. The four processes are absorption, distribution, metabolism, and excretion.
Drug Dissolution: The process by which a solid drug dissolves into a solution to be absorbed into the bloodstream. This is crucial for oral medications.
Excipients: Inert substances added to drugs to help with formulation, size, shape, or enhance dissolution.
Disintegration: The breakdown of oral drugs into smaller particles.
Dissolution: The combination of those particles with a liquid to form a solution for absorption.
First-pass effect: Metabolism of a drug in the liver before reaching systemic circulation, reducing the amount of active drug available.
Bioavailability: The percentage of administered drug available to produce the desired effect. Factors affecting it include drug form, administration route, gastric motility, food intake, and liver metabolism.
Passive transport: Drug movement down a concentration gradient without energy.
Active transport: Drug movement that requires energy and a carrier protein.
Pinocytosis: Drugs are engulfed in vesicles.
Blood-Brain Barrier (BBB): A tightly-packed endothelial lining of brain blood vessels, protecting the brain from drug entry.
Prodrug: An inactive compound converted to an active drug in the body. This enhances bioavailability or targets specific actions.
Half-life: The time it takes for half the drug in the body to be eliminated. Calculated from the rate of metabolism and excretion.
Highly protein-bound Drugs: Drugs that bind to >90% of plasma proteins. These are inactive.
Weakly protein-bound Drugs: Drugs that bind to <10% of plasma proteins. These are active.
Therapeutic Index (TI): The ratio of a drug's toxic dose to its therapeutic dose. A narrow TI requires close monitoring.
Agonists: Activate receptors to produce a full response.
Antagonists: Block receptors, preventing a response.
Partial agonists: Produce a moderate response, also potentially blocking the full response.
Tolerance: A gradual decrease in drug response over time.
Tachyphylaxis: A rapid decrease in drug response after the first dose.
Placebo Effect: A response to a drug due to psychological factors.
Drug-Induced Photosensitivity: A reaction to UV light exposure.

Conceptual Questions with Answers (Chapters 3 and 4)

Enteric-coated (EC) drugs: Not to be crushed before administration to protect them from stomach acid.
Gastric pH: Affects drug dissolution and absorption; acidic pH speeds things up, alkaline slows it down.
Villi: Increases surface area of small intestine for drug absorption. Decreased villi leads to decreased absorption.
Gastrointestinal tract factors: Gastric pH, blood flow, presence of food, gastric emptying time, and drug solubility affect drug absorption.
Protein-bound drug interactions: Affect the relative amount of active drug, increasing the risk of toxicity.

Application-Based Questions (Chapters 3 and 4)

Warfarin and furosemide: Potential for increased free drug levels of furosemide and increased bleeding risk due to displacement of warfarin by furosemide, from protein binding sites.
Hypoalbuminemia: Low albumin reduces protein binding, increasing free drug levels and increasing risk of toxicity. A load dose is needed to achieve therapeutic levels.
Phenytoin: A loading dose is needed, due to it's long half-life.

Additional Topics (Chapters 3 & 4)

Renal function and drug therapy: Impaired renal function reduces drug excretion, potentially leading to drug accumulation and toxicity.
Drug onset, peak, duration of action: Key considerations when monitoring drug efficacy and side effects.
Narrow therapeutic index drugs: Require close monitoring to avoid toxicity.
Enzyme inducers/inhibitors: Affect drug metabolism, affecting the effectiveness and potential toxicity of drugs.