Pharmacology and Drug Mechanisms Quiz

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Questions and Answers

What is pharmacology primarily concerned with?

The evaluation of drug therapeutic outcomes

The study of drug interactions and toxicity

The legal regulations surrounding drug use

The nature, actions, and mechanisms of drugs (correct)

What distinguishes a partial agonist from a full agonist?

A partial agonist activates a receptor but to a lesser degree than a full agonist. (correct)

A partial agonist only binds to receptors without activation.

A partial agonist has no effect on receptor activity.

A partial agonist fully activates a receptor while inhibiting it.

Which term refers to the elimination process of a drug from the body?

Elimination (correct)

Absorption

Distribution

Metabolism

Which statement best differentiates between competitive and non-competitive antagonism?

Competitive antagonism can be overcome by increasing agonist concentration, but non-competitive cannot. Signup and view all the answers

How does protein binding affect drug distribution and action?

It determines the amount of drug that is available to exert pharmacological effects. Signup and view all the answers

Which of the following is an example of a drug-induced disease?

Asthma Signup and view all the answers

What is the primary effect of a competitive antagonist?

It blocks the agonist's action by binding to the same site. Signup and view all the answers

What categorizes a drug as contraindicated?

It may cause harm to the patient if prescribed. Signup and view all the answers

Which type of drugs is known to cause teratogenesis?

Cytotoxic drugs Signup and view all the answers

What characterizes an antagonist compared to an agonist?

It prevents a receptor from producing a response. Signup and view all the answers

Which of the following best describes a partial agonist?

It activates the receptor but does not produce the maximum response. Signup and view all the answers

How do drug interactions occur?

Through combined pharmacological responses of multiple drugs. Signup and view all the answers

Which of the following is not a type of adverse drug reaction?

Increased efficacy Signup and view all the answers

What is the effect of enzyme induction on drug metabolism?

Decreases the efficacy of co-administered drugs Signup and view all the answers

Which drug is classified as an inhibitor of microsomal oxidation?

Metronidazole Signup and view all the answers

What occurs when microsomal enzymes are inhibited?

Reduced drug metabolism rates Signup and view all the answers

What is the primary role of the kidneys in drug excretion?

Filtration and removal of compounds based on size and charge Signup and view all the answers

Which of the following statements is true regarding microsomal enzymes?

CYP450 is an example of a microsomal enzyme involved in drug metabolism Signup and view all the answers

What is the primary function of a drug in the body?

To alter body functions at the molecular level Signup and view all the answers

Which of the following routes of drug administration is classified as enteral?

Rectal Signup and view all the answers

What is measured by the half-life of a drug?

The time it takes for the active substance to reduce by half Signup and view all the answers

What does pharmacokinetics specifically study?

What happens to drugs in the body Signup and view all the answers

What is the purpose of a loading dose?

To rapidly achieve a target steady state level Signup and view all the answers

What characterizes an adverse reaction to a drug?

Harmful effects occurring at therapeutic doses Signup and view all the answers

What is typically measured to determine whether a therapeutic effect has been achieved?

The level of the drug after 5 half-lives Signup and view all the answers

Which of the following refers to the study of how drugs affect the body?

Pharmacodynamics Signup and view all the answers

What is the primary function of a non-competitive antagonist?

Binds to an allosteric site on the receptor to prevent activation. Signup and view all the answers

Which route of exposure involves inhaling a chemical from particulate matter?

Inhalation Signup and view all the answers

What factor does NOT affect drug absorption?

Duration of action Signup and view all the answers

Which method of distribution allows molecules to move against a concentration gradient?

Special transport Signup and view all the answers

What is a key characteristic of passive diffusion?

Occurs from high to low concentration. Signup and view all the answers

Which characteristic does NOT relate to the characteristics of the body affecting absorption?

Lipid water solubility of the drug Signup and view all the answers

Which process involves the engulfing of solid substances by cells?

Phagocytosis Signup and view all the answers

Which is NOT a method by which small molecules cross biological lipid membranes?

Reverse osmosis Signup and view all the answers

Study Notes

Definitions

Pharmacology: The science concerned with drugs, their nature, actions, mechanisms, pharmacokinetics, uses, preparations, and administration.
Pharmacotherapeutics: The appropriate selection and application of drugs for disease prevention and treatment, focusing on therapeutic effects.
Toxicology: The study of adverse drug effects, including side effects, overdose toxicity, and allergic reactions.
Pharmacokinetics: The study of how drugs are absorbed, distributed, metabolized, and excreted (ADME) in the body.
Pharmacodynamics: The study of the effects of drugs on the body and their mechanisms of action.

Agonists, Partial Agonists, and Antagonists

Agonist: A drug that binds to receptors and mimics the action of the intended biological substance, producing a physiological response.
Partial Agonist: Binds to receptors but produces a lesser response than a full agonist.
Antagonist: Binds to receptors, blocking the action of agonists and preventing a physiological response.

Competitive vs Non-Competitive Antagonism

Competitive Antagonism: Antagonist competes with agonist for the same binding site on the receptor but does not activate it, preventing the agonist effect.
Non-Competitive Antagonism: Antagonist binds to a different site, inhibiting the receptor's activation regardless of agonist presence.

Drug Processes

Absorption: The process by which a drug enters the bloodstream, influenced by factors like lipid solubility and ionization.
Distribution: How the drug spreads through the body, crossing membranes via diffusion, filtration, special transport, and endocytosis.
Metabolism: The chemical modification of a drug, often involving liver enzymes like cytochrome P-450, affecting drug efficacy and toxicity.
Excretion: The elimination of drugs through kidneys, liver, skin, or lungs, based on molecular size and charge.

Drug Administration Routes

Enteral: Oral, sublingual, buccal, and rectal routes.
Parenteral: Intradermal, subcutaneous, intramuscular, intravenous, intra-arterial, intrathecal, intrapleural, intra-articular, and inhalation routes.
Topical: Administration via skin, ear, eye, nose, vaginal, and respiratory routes.

Half-Life and Steady State

Half-Life: Time taken for a drug's concentration to reduce by half; important for understanding dosing and scheduling.
Steady State: Achieved when drug intake equals elimination, typically occurring after five half-lives.

Factors Affecting Drug Absorption

Drug-related factors: Lipid/water solubility, molecular size, degree of ionization, dosage forms, and formulation.
Body-related factors: Surface area, vascularity, pH, GI motility, presence of other substances, and health of the absorptive surface.

Protein Binding and Drug Distribution

Protein binding affects drug distribution and therapeutic action; highly bound drugs may have altered efficacy.

Cytochrome P-450 Enzymes

Involved in drug metabolism; inducers increase enzyme activity leading to decreased drug efficacy, while inhibitors decrease activity, increasing toxicity risks.

Active vs Inactive Metabolites

Active Metabolites: Retain therapeutic activity.
Inactive Metabolites: No therapeutic effect, often resulting from drug metabolism.

Adverse Drug Reactions

Include side effects, toxicity, allergic reactions, iatrogenic diseases, and teratogenesis that can cause fetal abnormalities.
Contraindications exist when a drug should not be prescribed due to potential harm.
Drug interactions can alter the pharmacological effect, necessitating careful management.

Key Examples

Inductors: Drugs like phenobarbital can increase enzyme activity in drug metabolism.
Inhibitors: Metronidazole decreases enzyme activity, leading to increased drug toxicity.

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Description

Test your knowledge on key pharmacological concepts including agonists, antagonists, and the principles of pharmacokinetics and pharmacodynamics. This quiz covers essential definitions and applications in pharmacology and pharmacotherapeutics. Perfect for students and professionals alike.