Pharmacokinetics, Pharmacodynamics & Therapeutics (Video Notes)

Vocabulary flashcards covering key terms in pharmacokinetics, pharmacodynamics, routes of administration, and therapeutics based on the lecture notes.

Pharmacokinetics (PK)

The study of how drugs move through the body, described by ADME: Absorption, Distribution, Metabolism, and Elimination.

Pharmacodynamics (PD)

The study of what a drug does to the body, including drug–receptor interactions and resulting cellular effects.

Absorption

Process by which a drug enters the bloodstream from its site of administration; influenced by dosage form, route, and bioavailability.

Distribution

How the drug spreads from the bloodstream to tissues and organs; involves protein binding (e.g., albumin) and barriers like the blood–brain barrier.

Metabolism

Chemical modification of a drug, primarily in the liver; often converts active drugs to inactive metabolites; first-pass effect.

Elimination (Excretion)

Removal of drug from the body, mainly via kidneys (urine) and sometimes via feces; measured by CrCl or GFR.

Bioavailability

Fraction of an administered dose that reaches systemic circulation; IV ≈ 100%, oral usually less due to absorption and first-pass metabolism.

First-pass effect

Initial metabolism of oral drugs in the liver after intestinal absorption before reaching systemic circulation.

Cytochrome P-450 (CYP) enzymes

Family of liver enzymes that metabolize many drugs (e.g., CYP1A2, CYP2D6, CYP3A4).

CYP1A2

A member of the CYP family involved in metabolizing certain drugs; activity varies with genetics and interactions.

CYP2D6

A CYP enzyme with high genetic variability that metabolizes many drugs.

CYP3A4

A major hepatic CYP enzyme responsible for the metabolism of a large number of drugs; highly inducible and inhibited.

CYP inhibitors

Substances that decrease CYP enzyme activity, increasing drug levels and risk of toxicity.

CYP inducers

Substances that increase CYP enzyme activity, lowering drug levels and potentially reducing efficacy.

Serum half-life

Time required for the drug’s serum concentration to fall by 50%; influences time to steady-state (4–5 half-lives).

Loading dose

An initial higher dose to rapidly achieve therapeutic drug concentration.

Steady state

When the amount of drug administered equals the amount eliminated, producing a constant serum level.

Creatinine clearance (CrCl)

A measure of kidney function used to estimate drug elimination; normal ~120 mL/min (men) and ~95 mL/min (women).

Glomerular filtration rate (GFR)

Estimated rate at which the kidneys filter blood per minute; key measure of renal function.

Serum drug level

Measured concentration of a drug in the blood at a specific time, reflecting its duration in the body.

Albumin binding

Drugs can bind to plasma proteins (e.g., albumin); bound drug is inactive while free drug is pharmacologically active.

Oral administration (PO)

Drugs taken by mouth; convenient but with variable bioavailability and slower onset due to GI absorption and first-pass metabolism.

Sublingual/Buccal

Routes where drug is placed under the tongue or in the cheek for rapid absorption, often bypassing first-pass metabolism.

Inhalation

Administration as a gas or aerosol for rapid effects on the lungs; may affect respiration.

Topical & Transdermal

Drug routes applied to skin or mucous membranes; generally fewer systemic side effects but may irritate skin.

Intravenous (IV)

Delivery of drugs directly into the bloodstream; rapid action; nearly 100% of dose reaches circulation; sterile technique required.

Intramuscular (IM)

Injection into muscle; rapid absorption but volume limited and can be painful; avoid with anticoagulants.

Subcutaneous (Sub-Q)

Injection into tissue under the skin; slower absorption and usually small volumes.

PICC line

Peripherally Inserted Central Catheter; long-term IV access reducing needle sticks but more invasive with infection/clot risks.

PIV (Peripheral IV)

Peripheral intravenous access for drug administration; easier but shorter-term and with infection risk.

Agonist

Drug that binds to a receptor and activates it, producing a biological response.

Antagonist

Drug that binds to a receptor but does not activate it, blocking receptor activation.

Drug–receptor interaction

Binding of a drug to a cellular receptor to produce a pharmacologic effect.

Receptor theory

Concept explaining drug effects via receptor binding, including agonist/antagonist dynamics.

Blood-brain barrier

Protective barrier that limits drug entry into the brain, affecting CNS distribution.

Therapeutics

Uses of drugs to diagnose, treat, prevent disease, cure, or alleviate symptoms.