02 How Medicines Work in the Body Free Online FlashCards

What does pharmacokinetics describe?

Pharmacokinetics describes how the body handles a drug through absorption, distribution, metabolism, and excretion (ADME).

What does pharmacodynamics describe?

Pharmacodynamics describes a drug’s effects and how it produces them.

What is the first-pass effect?

The first-pass effect is metabolism of some of an oral drug in the gut or liver before it reaches the circulation.

Which portion of a drug is generally readily available to act on tissues?

Distribution moves a drug through the blood into body tissues. The unbound portion is generally more readily available to act on tissues.

What can happen to a drug during metabolism?

Metabolism chemically alters a drug, usually through liver enzymes; it may inactivate the drug, activate an inactive drug, or produce active or harmful metabolites.

How can enzyme inhibition and induction affect another drug?

Enzyme inhibition can raise another drug’s concentration, while enzyme induction can lower it; either may change treatment effects or adverse-reaction risk.

How can reduced kidney function affect drug levels?

Excretion removes a drug or its metabolites. The kidneys are a major route, and reduced kidney function can slow removal and allow certain drugs to accumulate.

What is a drug’s half-life?

A drug’s half-life is the time it takes for its amount or concentration in the body to fall by about half.

How do an agonist and an antagonist differ?

An agonist activates a receptor; an antagonist blocks or reduces its activation.

Why does a narrow therapeutic range require care?

A narrow therapeutic range means small changes in dose or drug concentration can matter because the balance between expected benefit and risk is sensitive.

Name factors that can make drug responses differ between people.

Responses can differ with age, body composition, organ function, genetics, interactions, health status, prior exposure, and administration factors.

What should be verified before administering a medicine?

Follow the medication order and required safety checks; verify the patient, medicine, dose, route, and time, and review relevant allergies, vital signs, laboratory results, and precautions.