Pharmacology Terminology to Know for Intro to Pharmacology

Understanding pharmacology terminology is essential for grasping how drugs work in the body. Key concepts include drug classification, pharmacokinetics, and pharmacodynamics, which explain how drugs are absorbed, distributed, metabolized, and how they interact with receptors to produce effects.

1. Drug

   • A substance used to diagnose, treat, or prevent disease.
   • Can be natural or synthetic and may have therapeutic or non-therapeutic effects.
   • Classified by their chemical structure, mechanism of action, or therapeutic use.

2. Pharmacokinetics

   • The study of how the body absorbs, distributes, metabolizes, and excretes drugs.
   • Involves four main processes: absorption, distribution, metabolism, and excretion (ADME).
   • Helps determine the onset, duration, and intensity of a drug's effect.

3. Pharmacodynamics

   • The study of the biochemical and physiological effects of drugs and their mechanisms of action.
   • Focuses on how drugs interact with receptors and produce therapeutic effects.
   • Involves concepts like agonists, antagonists, and dose-response relationships.

4. Absorption

   • The process by which a drug enters the bloodstream from its site of administration.
   • Influenced by factors such as the drug's formulation, route of administration, and the presence of food.
   • Affects the onset of action and overall bioavailability of the drug.

5. Distribution

   • The dispersion of a drug throughout the body's fluids and tissues after absorption.
   • Influenced by factors like blood flow, tissue permeability, and protein binding.
   • Determines the concentration of the drug at the site of action.

6. Metabolism

   • The chemical alteration of a drug by the body, primarily in the liver.
   • Converts drugs into more water-soluble compounds for easier excretion.
   • Can result in active metabolites that may enhance or diminish the drug's effects.

7. Excretion

   • The process of eliminating drugs and their metabolites from the body, primarily through urine or feces.
   • Renal function plays a significant role in drug clearance.
   • Impaired excretion can lead to drug accumulation and toxicity.

8. Half-life

   • The time it takes for the concentration of a drug in the bloodstream to reduce by half.
   • Influences dosing schedules and duration of drug action.
   • Affected by factors such as metabolism and excretion rates.

9. Bioavailability

   • The proportion of a drug that enters the circulation when introduced into the body and is available for action.
   • Affected by the route of administration and first-pass metabolism.
   • Critical for determining the appropriate dosage for effective treatment.

10. Therapeutic index

    • A measure of the safety of a drug, defined as the ratio between the toxic dose and the effective dose.
    • A higher therapeutic index indicates a safer drug with a wider margin for error.
    • Important for assessing the risk of adverse effects.

11. Agonist

    • A substance that binds to a receptor and activates it, producing a biological response.
    • Can mimic the action of naturally occurring substances in the body.
    • Examples include morphine (an opioid agonist) and albuterol (a beta-agonist).

12. Antagonist

    • A substance that binds to a receptor but does not activate it, blocking the action of agonists.
    • Can prevent or reduce the effects of endogenous substances or other drugs.
    • Examples include naloxone (an opioid antagonist) and propranolol (a beta-antagonist).

13. Dose-response curve

    • A graphical representation of the relationship between drug dose and the magnitude of its effect.
    • Helps determine the potency and efficacy of a drug.
    • Can illustrate concepts like threshold dose, maximal effect, and variability among individuals.

14. Side effect

    • An unintended, often mild effect of a drug that occurs in addition to its therapeutic effects.
    • Can be predictable or unpredictable and vary in severity.
    • Examples include drowsiness from antihistamines or gastrointestinal upset from antibiotics.

15. Adverse drug reaction

    • An unwanted or harmful reaction to a drug that occurs at normal doses.
    • Can be serious and may require medical intervention or discontinuation of the drug.
    • Examples include allergic reactions, organ toxicity, or severe interactions.

16. Drug interaction

    • Occurs when one drug affects the pharmacokinetics or pharmacodynamics of another drug.
    • Can enhance or diminish the effects of one or both drugs, leading to potential toxicity or therapeutic failure.
    • Important to consider in polypharmacy situations.

17. Tolerance

    • A reduced response to a drug after repeated use, requiring higher doses to achieve the same effect.
    • Can develop due to physiological adaptations or changes in drug metabolism.
    • Common in chronic pain management and substance use disorders.

18. Dependence

    • A state in which the body adapts to a drug, leading to withdrawal symptoms when the drug is not taken.
    • Can be physical (physiological changes) or psychological (craving for the drug).
    • Important in the context of addiction and substance use disorders.

19. Withdrawal

    • A set of symptoms that occur when a dependent individual reduces or stops taking a drug.
    • Symptoms can range from mild to severe and vary depending on the substance.
    • Management may require medical supervision and supportive care.

20. Receptor

    • A protein molecule on the surface of cells that binds to specific substances (ligands) like drugs or hormones.
    • Activation of receptors triggers a series of cellular responses, leading to the drug's effects.
    • Types of receptors include ion channels, G-protein coupled receptors, and enzyme-linked receptors.