Principles of Pharmacology
The two halves of pharmacology: what the body does to the drug (pharmacokinetics — ADME) and what the drug does to the body (pharmacodynamics — receptors, dose–response, safety).
Overview & Routes
The big picture — the drug's whole ADME journey, and every door into the body.
Absorption
How a swallowed drug actually gets into your blood — and what slows it.
Distribution
Where the drug travels after the blood — protein binding, barriers, and volume of distribution.
Metabolism
The liver's chemistry set — first pass, CYP enzymes, and drug interactions.
Excretion
How the body clears a drug out — kidneys, bile, and dosing when they fail.
Kinetics & Dosing
The numbers that run every prescription — clearance, half-life, steady state, and dosing.
Pharmacodynamics: Foundations
The other half — what the drug does to the body, and the targets it acts on.
Receptors & Signalling
Receptor families and how a drug's message gets amplified inside the cell.
Drug–Receptor Interactions
Agonists, antagonists, affinity, efficacy, potency — the language of drug action.
Dose, Response & Safety
Dose–response curves and the margin between a helpful dose and a harmful one.
Adaptation & Variability
Why effects fade with repeated dosing, and why the same dose acts differently in different people.
PK + PD Together
Joining both halves — the time course of a drug's effect from first dose to worn off.
How the Body Handles a Drug: The ADME Story
You swallow one small tablet for a fever. Over the next eight hours that tablet is absorbed, carried, chemically rebuilt, and finally thrown out — a four-act journey the body performs on every drug you ever take. Learn the four acts (ADME) and one simple curve, and you can predict how fast a drug works, how long it lasts, and why the same dose can be safe in one patient and toxic in another.
Every Door Into the Body: Routes of Administration
The same drug can save a life in ten seconds or ten minutes — depending only on which door you send it through. Swallowed, injected, inhaled, slipped under the tongue, or stuck to the skin: each route trades speed for safety, convenience for control. Learn the doors and you'll understand why a code-blue drug goes in a vein while a nicotine patch goes on an arm.
The Drug's Journey: What Absorption Really Is, and How a Drug Crosses Your Cells
You swallow a tablet for a headache. It doesn't know where your head is. Yet 30 minutes later the pain fades. Between the swallow and the relief lies one of the most underestimated journeys in medicine — absorption. Let's follow the drug, step by step, and never forget how it works.
What Controls How Much and How Fast: pH, pKa, First-Pass and Bioavailability
In Part 1 the drug learned HOW to cross a membrane. Now the harder question: why does the same drug act in 15 minutes on an empty stomach but 45 after a meal — and why is a tiny nitroglycerin tablet placed under the tongue instead of swallowed? The answers are pH, surface area, blood flow, formulation, and the liver's first tax. Master these and you can predict a drug's behaviour before you ever prescribe it.
Where Drugs Travel: Distribution & Plasma Protein Binding
Once a drug reaches the blood, the journey isn't over — it's just beginning. The bloodstream is a highway, but most of a drug never rides free: it hitches onto blood proteins like passengers strapped into seats, and only the few standing by the doors can actually step off and work. Understand who rides bound and who rides free, and you'll understand why one tiny new pill can suddenly make a patient on warfarin bleed.
