Pharmacokinetics, Pharmacodynamics, and Pain Management Pharmacology

Vocabulary flashcards focusing on core concepts of pharmacokinetics, pharmacodynamics, pain pathways, non-opioid analgesics, NSAIDs, opioids, muscle relaxants, and anti-migraine therapy based on NU226 lecture slides.

Pharmacokinetics

The study of what happens to a drug from the time it enters the body until the parent drug and all metabolites have left the body, encompassing absorption, distribution, metabolism, and excretion (ADME).

Absorption

The rate at which a drug leaves its site of administration and passes into the systemic circulation.

Bioavailability

The proportion of an administered drug that enters the systemic circulation and is able to exert an active effect.

First-Pass Effect

The hepatic metabolism of an orally ingested drug before reaching systemic circulation, reducing its bioavailability to less than $100\%$.

Distribution

The transport of drugs within body fluids from the bloodstream to sites of action, elimination, and body tissues.

Blood-Brain Barrier

A protective blockade composed of a tightly woven mesh of capillaries that limits the movement of potentially dangerous substances from the blood into brain tissue.

Metabolism (Biotransformation)

The chemical alteration of a drug by body systems into compounds that are more easily excreted, primarily occurring in the liver.

Enzyme Induction

A process where the liver increases enzyme production, resulting in faster drug breakdown and potentially requiring a higher dosage.

Enzyme Inhibition

A mechanism where liver enzymes are blocked, causing slower drug breakdown and increasing the risk of toxicity.

Excretion

The elimination of parent drugs or active/inactive metabolites from the body, primarily mediated by the kidneys.

Pharmacodynamics

The study of how drugs act on specific target sites of action in the body.

Drug Half-Life

The time required for the concentration of active drug in the body to decrease by $50\%$.

Onset of Action

The time required after administration for a drug to elicit a therapeutic response.

Peak Effect

The time required for a drug to reach its maximum concentration in the body and achieve its highest therapeutic response.

Duration of Action

The length of time that drug concentrations remain sufficient to elicit a therapeutic response without additional doses.

Loading Dose

A large initial dose administered to rapidly achieve constant drug blood levels (plateau), followed by maintenance dosing.

Therapeutic Index

A quantitative measurement of the relative safety of a drug, reflecting the margin between effective concentration and toxic concentration.

Drug Potency

The amount or concentration of a drug required to produce a desired therapeutic effect.

Nociception

The physiological processing of harmful chemical, mechanical, or thermal stimuli through a normally functioning nervous system.

A-delta Fibers

Myelinated nerve fibers responsible for transmitting localized, fast pain sensations.

Unmyelinated C Fibers

Nerve fibers responsible for transmitting poorly localized, dull pain sensations.

Pain Threshold

The minimum intensity of a stimulus that an individual perceives as painful.

Pain Tolerance

The maximum intensity of pain that an individual can endure in a given situation.

Acute Pain

Transient, protective pain lasting up to $3$ to $6\text{ months}$ that has a direct cause and resolves with normal tissue healing.

Chronic Pain

Non-protective pain that persists or recurs frequently for longer than $3$ to $6\text{ months}$, lasting beyond expected tissue healing time.

Somatic Pain

Pain originating from the skin, joints, and muscles, characterized as sharp or dull.

Visceral Pain

Poorly localized, aching, gnawing, or cramping pain originating from internal organs and body cavity linings.

Referred Pain

Pain perceived in a location distant from its original point of origin due to shared spinal cord innervation.

Neuropathic Pain

Intense, burning, shooting, or shock-like pain caused by dysfunction or structural damage within peripheral or central nervous pathways.

Nociplastic Pain

Pain arising from altered nociception without clear evidence of actual or threatened tissue damage (e.g., fibromyalgia).

Cyclooxygenase-1 (COX-1)

An enzyme present in all tissues that protects gastric mucosa, regulates renal blood flow, and stimulates platelet aggregation.

Cyclooxygenase-2 (COX-2)

An enzyme induced at tissue injury sites that promotes inflammation and sensitizes pain receptors to painful stimuli.

First-Generation NSAIDs

Non-selective nonsteroidal anti-inflammatory drugs (e.g., Ibuprofen, Naproxen, Aspirin) that inhibit both COX-1 and COX-2 enzymes.

Reye's Syndrome

A severe complication marked by brain swelling and liver damage, triggered when aspirin is administered to children or adolescents under $18\text{ years}$ of age with viral illnesses.

Celecoxib

A second-generation, COX-2 selective NSAID that treats musculoskeletal pain and inflammation with decreased risk for gastrointestinal bleeding.

Acetaminophen

A central antipyretic and analgesic agent that decreases pain perception in the brain without inhibiting peripheral inflammation, limited to a maximum dose of $4\,g/day$.

Morphine

A prototype strong opioid agonist that binds Mu and Kappa receptors to modulate pain perception and produce analgesia.

Fentanyl

A synthetic opioid agonist that is up to $50\times$ stronger than heroin and $100\times$ stronger than morphine.

Tramadol

A Schedule IV centrally acting analgesic that blocks uptake of norepinephrine and serotonin and acts as a weak Mu-opioid agonist.

Naloxone (Narcan)

An opioid antagonist that displaces opioids from Mu and Kappa receptors to reverse respiratory and CNS depression during an opioid overdose.

Gabapentin

An anticonvulsant GABA analogue used to treat neuropathic pain by enhancing GABA release to inhibit neuronal firing.

Pregabalin

A Schedule V GABA analogue that binds to voltage-gated calcium channels on nerve terminals to inhibit excitatory neurotransmitter release.

Sumatriptan

A serotonin receptor agonist used for acute migraine treatment by inducing cranial vasoconstriction; contraindicated in coronary artery disease.