Lecture 1 Introduction to pharmacology (NO PHARMACOLOGY HISTORY)

Term: Pharmacology

Definition: The science of drugs (pharmakon = drug/medicine, logos = discourse). It is the study of drug action and fate in the body. It aims to identify drug targets and understand how drugs work by interacting with them, and to understand how drugs are handled/modified by the living organism.

Term: Toxicology

Definition: A science focusing on chemicals with harmful effects. It deals with undesirable effects of chemicals on living systems.

Term: Therapeutics

Definition: The treatment of disease (using drugs or other means).

Term: Drug

Definition: Any substance that brings about a change in biologic function through its chemical actions. According to the FDA definition, it includes "articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease" and "articles (other than food) intended to affect the structure or any function of the body of man or other animals". Essential nutrients and endogenous compounds can also be drugs.

Term: Drug target

Definition: The specific molecule in the body that a drug interacts with to produce its effects. This is often a receptor, enzyme, or other molecule.

Term: Agonist

Definition: A drug that activates a receptor and produces a biological response, often mimicking a natural compound.

Term: Antagonist

Definition: A drug that inhibits the action of an agonist or a natural ligand by binding to a receptor but not activating it.

Term: Pharmacokinetics (PK)

Definition: ‘WHAT THE BODY DOES TO THE DRUG’. It is the study of the kinetics (time course) of drug concentrations and the various processes and factors that affect it. It quantitatively describes the various steps of drug disposition in the body: Absorption (F, Cmax, Tmax), Distribution to various organs and tissues (Vd), and Elimination by metabolism and excretion (k, Cl, t1/2). These processes determine the plasma concentration a particular drug dose reaches following administration.

Term: Pharmacodynamics (PD)

Definition: ‘WHAT THE DRUG DOES TO THE BODY’. It involves the study of the effects and mechanisms of therapeutic and toxic action of a drug. It describes the interaction with the target (receptors/enzymes/molecules), resulting in physiological/biochemical changes.

Term: ADME

Definition: An acronym representing the four main pharmacokinetic processes: Absorption,
Distribution, Metabolism, and Excretion. These processes determine the time course of drug concentration in blood and tissues following drug administration.

Term: Absorption

Definition: The movement of the drug from its site of administration into the bloodstream. Key parameters include Bioavailability (F), Cmax (peak concentration), and Tmax (time to peak concentration).

Term: Distribution

Definition: The spreading of the drug throughout the body once absorbed, from systemic circulation to intracellular and interstitial fluid. The extent of distribution is quantified by the Volume of Distribution (Vd).

Term: Metabolism (Biotransformation)

Definition: The transformation of the drug to more hydrophilic metabolites, primarily in the liver. This is usually an enzyme-mediated inactivation.

Term: Excretion

Definition: The removal of drug from the body, primarily by the kidney, but also in bile, breath (for volatile compounds), sweat, saliva, and breast milk.

Term: Drug concentration

Definition: The amount of drug present in a specific volume of fluid, such as plasma. Pharmacokinetics studies the time course of drug concentration.

Term: Drug dosing

Definition: The determination and administration of the appropriate amount of drug to achieve a therapeutic effect. PK data is used to determine dosing.

Term: Therapeutic benefit

Definition: The positive effects of a drug in treating a disease or condition.

Term: Adverse effects

Definition: Unintended and harmful effects that occur as a result of taking a drug.

Term: Toxicity

Definition: All possible toxic drug effects with any use/dose, including poisoning and overdoses.

Term: Drug administration

Definition: The process by which a drug is introduced into the body.

Term: Therapeutic Index (T.I.)

Definition: A measure of drug safety, calculated as the ratio of the Toxic Dose (TD50) to the Effective Dose (ED50). A larger T.I. generally indicates a safer drug.

Term: Bioequivalence

Definition: When two different drug preparations with equal dosage form produce similar pharmacokinetic measures.

Term: Generic Name

Definition: The officially approved name of a drug, which is non-proprietary and the same in all countries. Examples include Acetaminophen and Ibuprofen.

Term: Trade Name (Proprietary Name)

Definition: The brand name assigned by the manufacturer to a drug, which is proprietary (trademarked). Examples include Tylenol® and Advil®.

Term: Drug receptor

Definition: A specific target molecule that a drug interacts with, usually a protein, to initiate a pharmacological effect.