What does pharmacokinetics mean?
What the body does to a drug.
What does pharmacodynamics mean?
What the drug does to the body.
What are the five stages of pharmacokinetics (LADME)?
Liberation, Absorption, Distribution, Metabolism, Excretion.
What is drug liberation?
The drug being released from its form (e.g., tablet → active ingredient).
What is absorption?
The process of a drug entering the bloodstream.
Name factors affecting absorption.
Drug form, lipid solubility, stomach pH, food, surface area, first-pass metabolism.
What is the first-pass effect?
The liver breaking down oral drugs before they reach systemic circulation.
Name drugs with high first-pass metabolism.
Aspirin, Morphine, Propranolol, GTN, Lidocaine.
What is bioavailability?
The percentage of drug reaching the bloodstream.
What route gives 100% bioavailability?
Intravenous (IV).
What does bioequivalence mean?
Two drugs have the same effect and availability at the site of action.
What are biosimilars?
Biologic drugs that are similar but not identical to the original medicine.
What affects drug distribution?
Blood flow, plasma protein binding, fat stores, and barriers (e.g., brain).
Why is plasma protein binding important?
Only unbound (free) drug is active.
What happens if albumin is low?
More free drug → stronger effect or toxicity.
Example of drug displacement interaction?
Warfarin + Aspirin → increased bleeding risk.
Where does most drug metabolism occur?
Liver.
What are prodrugs?
Inactive drugs that must be metabolized to become active (e.g., codeine → morphine).
What are enzyme inducers?
Drugs that speed up metabolism (need higher doses).
What are enzyme inhibitors?
Drugs that slow metabolism (need lower doses).
Main organ for drug excretion?
Kidneys.
Name other routes of excretion.
Bile, sweat, lungs, milk, saliva.
Drugs largely excreted unchanged?
Furosemide, Gentamicin, Methotrexate, Atenolol, Digoxin.
What is the therapeutic index (TI)?
The range between effective and toxic dose.
