Pharmacokinetics and Clinical Pharmacology – Week 3 (Vocabulary Flashcards)

Vocabulary flashcards covering key pharmacology concepts from Week 3 notes on pharmacokinetics, pharmacogenetics, ADRs, drug interactions, and pharmacovigilance.

Pharmacokinetics

The study of how the body handles a drug, i.e., the movement of drugs through Absorption, Distribution, Metabolism, and Excretion.

ADME

The four stages of pharmacokinetics: Absorption, Distribution, Metabolism, Excretion.

Absorption

Process by which a drug enters the bloodstream from its site of administration; influenced by pH, blood flow, surface area; affects bioavailability.

Distribution

Spread of a drug from the bloodstream into tissues and organs; influenced by protein binding and tissue affinity.

Metabolism

Biotransformation of drugs, typically in the liver; involves Phase I and Phase II reactions and is affected by genetics and enzyme induction/inhibition.

Excretion

Elimination of drugs from the body, mainly via kidneys; related to renal function and age.

Pharmacogenetics

How an individual's genetic makeup affects their response to drugs.

Genetic polymorphism

Variation in DNA sequence between individuals.

SNP

Single nucleotide polymorphism; substitution of one nucleotide that can alter enzymes, transporters, or targets.

CYP enzymes

Cytochrome P450 enzymes that metabolize many drugs; genetic polymorphisms affect activity.

Poor metaboliser

Individual with little to no activity of a given CYP enzyme, leading to slower drug metabolism.

Intermediate metaboliser

Reduced enzyme activity leading to slower metabolism than normal.

Extensive metaboliser

Normal enzyme activity; typical drug metabolism.

Ultra-rapid metaboliser

Increased enzyme activity leading to faster metabolism and potentially reduced drug efficacy.

Ethnic polymorphisms

Genetic polymorphisms with varying frequency across ethnic groups; can affect drug response (e.g., alcohol metabolism variants).

Adverse Drug Reaction (ADR)

Noxious, unintended reaction to a drug occurring at normal doses.

ADR risk factor – age

Very young and elderly have higher ADR risk due to different metabolism and excretion.

ADR risk factor – gender

Gender differences can affect pharmacokinetics and drug responses.

ADR risk factor – genetics

Genetic polymorphisms can affect metabolism, transport, and targets.

ADR risk factor – pre-existing conditions

Chronic diseases can impair clearance and increase ADR risk.

ADR risk factor – allergies

History of drug allergies increases risk of hypersensitivity reactions.

Polypharmacy

Use of multiple medications, increasing the risk of drug interactions and ADRs.

Dose and duration

Higher doses and longer use can raise risk of toxicity.

Route of administration (ADR risk)

Some routes (e.g., intravenous) can cause more immediate or severe ADRs.

Pharmacovigilance

Monitoring and reporting of adverse drug reactions to ensure drug safety.

Grapefruit–drug interaction

Grapefruit components inhibit intestinal CYP3A4, raising the bioavailability of some drugs (effect may last up to 3 days).

Bioavailability

Fraction of an administered dose that reaches systemic circulation; influenced by formulation and absorption.

Drug interactions – three categories

Interactions outside the body, in the GI tract, and after absorption.

Drug incompatibility

Chemical incompatibility when drugs are mixed in the same syringe or container.

Drug interactions in GI tract

Affect absorption and bioavailability; formulation and food can alter absorption.

Drug interactions after absorption (PK/PD)

Interactions that alter distribution, metabolism, excretion, or pharmacodynamics after absorption.

Additive pharmacodynamics

Combined effect of two drugs with similar effects equals the sum of their individual effects.

Synergistic pharmacodynamics

Combined effect greater than the sum of individual effects.

Antagonistic pharmacodynamics

One drug reduces or opposes the effect of another.

Naloxone and opioids (receptor interaction)

Naloxone competes at the mu-opioid receptor to reverse opioid effects.