Veterinary Pharmacology: Pharmacokinetics and Drug Administration

Flashcards summarizing key concepts from a lecture on pharmacokinetics, pharmacodynamics, drug administration, and veterinary pharmacology.

What is pharmacokinetics?

The study of the movement of drugs within the body.

List the four steps of pharmacokinetics.

Absorption, Distribution, Metabolism, Elimination/Excretion.

What is absorption in the context of pharmacokinetics?

Getting the drug into the bloodstream.

What does distribution refer to in pharmacokinetics?

Moving the drug around in the body to reach its site of action.

Define metabolism in drug pharmacokinetics.

Changing the drug into a form that can be eliminated from the body.

What is meant by elimination/excretion in pharmacokinetics?

Getting the drug out of the body.

What is bioavailability?

The extent and rate at which the active ingredient or active moiety is absorbed and becomes available at the site of action.

What is the first-pass effect?

The metabolism of a drug in the liver before it reaches systemic circulation.

How does blood supply to an area affect drug absorption?

Increased blood supply to an area increases the rate of absorption.

What is the difference between IV and SQ absorption rates?

IV absorption is faster than SQ due to increased blood supply to muscle compared to subcutaneous space.

How does the GI status affect drug absorption?

Conditions like hyper/hypomotility, vomiting, or inflammation can affect absorption rates.

What factors can affect drug absorption?

Type of administration, blood supply to the area, drug formulation, and drug characteristics.

What is meant by passive diffusion in drug absorption?

Movement of drug molecules along a concentration gradient through a permeable membrane.

Describe facilitated diffusion.

Movement along a concentration gradient assisted by a special carrier molecule.

What is active transport in drug absorption?

Transport of substances against a concentration gradient requiring energy and a carrier molecule.

What is pinocytosis?

The active uptake of substances by cells through vesicles.

Where is the largest area of drug absorption in the body?

The small intestine, due to its design of folded villi that increase surface area.

How does pH affect drug absorption?

pH affects the ionization of drug molecules; more non-ionized (lipophilic) molecules are better absorbed.

What is a weak acid like aspirin's absorption mechanism in the stomach?

On an empty stomach, aspirin is more non-ionized due to stomach acid, enhancing absorption.

What effect do diet and food have on drug absorption?

Certain foods can alter absorption; for example, milk can neutralize stomach acid affecting aspirin absorption.

Define biotransformation in relation to metabolism.

The body's ability to chemically change a drug to a form that can be eliminated.

How do liver enzyme systems affect drug metabolism?

Young animals may not fully metabolize drugs because their liver enzyme systems are not fully developed.

Which species is noted for having difficulties in metabolizing certain drugs?

Cats, as they cannot produce glucuronic acid.

What is the primary route through which most drugs are excreted?

By the kidneys via urine.

What happens if kidneys are not functioning properly regarding drug excretion?

Drugs may accumulate to toxic levels in the body.

Describe the different routes of drug excretion besides kidneys.

Bile via liver, mammary glands, lungs, intestinal tract, sweat, salivary glands, and skin.

What is the significance of a therapeutic range?

The range of drug concentrations that produces desired effects with minimal toxicity.

What is meant by steady-state in pharmacokinetics?

The point at which drug accumulation equals elimination after repeated doses.

Define minimum effective concentration (MEC).

The lowest concentration of drug needed to produce a therapeutic effect.

What is the maximum safe concentration (MSC)?

The highest concentration of drug that can be safely tolerated without toxicity.

What is the duration of action in pharmacokinetics?

The length of time the drug concentration is at or above the MEC.

What is drug dose?

The total amount of drug administered at one time.

How is dosage different from dose?

Dosage refers to the amount of drug per unit of body weight.

What does half-life indicate in pharmacokinetics?

The time required for the amount of drug in the body to be reduced by half.

How is therapeutic index calculated?

By dividing the LD50 (lethal dose for 50% of patients) by the ED50 (effective dose for 50% of patients).

Define pharmacodynamics.

The study of how drugs produce their therapeutic effects and any adverse effects.

What is an agonist?

A drug with high affinity and efficacy that activates receptors.

What is an antagonist in pharmacodynamics?

A drug with high affinity for receptors but no efficacy.

What is an adverse drug event?

Harm caused by the administration of a drug for therapeutic or diagnostic reasons.

What is an idiosyncratic drug reaction?

An unusual or unexpected reaction to a drug that is not dose-dependent.

What are the main types of drug interactions?

Pharmacokinetic, pharmacodynamic, and pharmaceutical interactions.

What does the general formulation of drug names include?

Chemical name, code name, generic name, and trade name.

What needs to be on a medication label?

Facility name, vet's name, owner's name, patient's details, drug name and strength, instructions, expiration date.

What is meant by 'dispense as written'?

A directive on prescriptions indicating the pharmacist should not substitute a generic for the brand name.

Identify factors that can affect drug duration of action.

Drug dose, half-life, and dosing interval.

Define loading dose.

A larger-than-usual initial dose given to quickly achieve effective drug levels.

What is the significance of a maintenance dose?

The dose regimen that keeps the drug in its therapeutic range.

Why is it important to record drug doses accurately?

To ensure proper administration and to avoid confusion with different drug formulations.

What does the dosing interval refer to?

The time between successive doses of a drug administration.

What instruction does PRN stand for in medication administration?

As needed.

What does BID stand for in medication abbreviations?

Twice daily.

What is the role of the kidneys in drug metabolism and excretion?

They filter drug molecules from the blood into urine and secrete metabolites.

Why is therapeutic drug monitoring important?

To ensure drug levels remain within therapeutic range to avoid under or overdosing.

What are the effects of a high lipid solubility drug?

Better drug absorption but may hinder distribution.

Why is proper training in medication administration crucial?

To prevent errors related to drug names, dosages, and routes of administration.

What is meant by pH being lipophilic or hydrophilic for drug absorption?

Non-ionized (lipophilic) drugs are better absorbed while ionized (hydrophilic) drugs are less absorbed.

What factors can significantly alter the absorption process after oral drug ingestion?

Condition of the GI tract, presence of food, and drug characteristics.

Define and explain the importance of the therapeutic drug monitoring process.

It ensures appropriate drug levels are maintained to be effective without causing toxicity.

Explain what a toxic dose is.

A dose that exceeds the maximum safe concentration resulting in harmful effects.