Pharmacodynamics and Pharmacokinetics: Key Concepts in Drug Action and Metabolism

Pharmacodynamics

What a drug does to the body

Therapeutic

Difference between effective dose and a lethal dose

Pharmaceutic

Relating to pharmacy

Mechanism of Action

How medication does what it does

Half-life

Rate by which a drug is metabolized and broken down to one-half of the original concentration

Onset

Length of time it takes for a medication to be distributed

Peak

When the medication will likely work

Indications

Signs or symptoms that guide care

Agonist

Drug or chemical that binds to a cell receptor and activates it to produce a biological response

Antagonist

Substance that stops the action or effect of another substance

Warfarin

Oral anticoagulant used to prevent and treat thromboembolic disorders

Absorption

How a drug enters the bloodstream

Distribution

Where a drug goes once it enters the bloodstream

Metabolism

How a drug is broken down by the body

Excretion

How a drug leaves the body

Bioavailability

How much of an administered drug actually reaches the correct site

Loading Dose

An initial larger dose of a medication given when a medication has a long half-life

First Pass Effect

Concept of a drug being partially metabolized before reaching its target, making the dose weaker

Synergistic Effect

When two things work together to increase the effect of a drug

Paradoxical Effect

When a drug causes the opposite of its intended purpose

Blood Brain Barrier

Highly selective semi-permeable membrane that protects the CNS from pathogens and toxins

Intrathecal

When something is injected into the fluid-filled space surrounding the spinal cord and brain

Parenteral

Introducing a medication in a way that isn't through the digestive tract

Apoptosis

Programmed orderly death of cells

Atrophy

Partial or complete wasting away/reduction in size of a body part

Hypertrophy

Increase in muscle size

Necrosis

Sudden cell death of cells and living tissue