Understanding Pharmacokinetics and Pharmacodynamics in Anesthesia
dorothy prieto
What is the definition of bioavailability?
The rate and extent of drug absorption from a dosage form.
What does pharmacokinetics study?
The rate processes involved in the absorption, distribution, metabolism, and excretion of drugs.
What does ADME stand for in pharmacokinetics?
Absorption, Distribution, Metabolism, Excretion.
What is the focus of pharmacodynamics?
The relationship between drug concentration at the site of action and the pharmacologic response.
What is a full agonist?
A substance that binds to and activates a receptor, producing maximal biological response.
Define a partial agonist.
A substance that binds to and activates a receptor but does not produce a maximal response.
What is a neutral antagonist?
A substance that binds to a receptor but does not activate it, competing with agonists for receptor binding.
What effect does an inverse agonist have on a receptor?
It induces an effect opposite to that of an agonist and reduces the constitutive activity of the receptor.
What is the primary process of drug disposition?
Absorption.
What is the significance of the intravenous (IV) route in drug administration?
In IV administration, there is no absorption, resulting in 100% bioavailability.
Which part of the gastrointestinal tract is the most important site for drug absorption?
Small intestine.
What is the Henderson-Hasselbalch Equation?
pH = pK_a + log ( [A^-] / [HA] )
How do acidic drugs behave in an acidic medium according to the Henderson-Hasselbalch Equation?
Acidic drugs are non-ionized.
What physiological factor affects gastric emptying rate (GER)?
Body position can influence GER.
How does a fatty meal affect drug absorption?
Fatty meals decrease absorption except for certain drugs.
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Description
Explore the key concepts of pharmacokinetics and pharmacodynamics, focusing on drug absorption, distribution, metabolism, and excretion, as well as their implications in anesthesia and pain management.
Questions
Download Questions1. What does pharmacokinetics study?
2. Which of the following accurately describes a full agonist?
3. What is the main site for drug absorption in the gastrointestinal tract?
4. What does bioavailability refer to?
5. Which drug undergoes first-pass effect and has rapid hepatic metabolism?
6. What is the primary function of albumin in drug distribution?
7. Which phase of drug metabolism involves oxidation, reduction, deamination, and hydrolysis?
8. Which of the following is a characteristic of a neutral antagonist?
9. Which part of the gastrointestinal tract has the largest surface area for drug absorption?
10. What effect does lying on the right side have on gastric emptying rate (GER)?
Study Notes
Pharmacokinetics and Pharmacodynamics in Anesthesia
This document provides an integrated overview of pharmacokinetics and pharmacodynamics as they relate to anesthesia, highlighting the mechanisms of drug action, absorption, and their implications for patient care during surgical procedures.
Anesthesia Overview
- Types of Anesthesia: General anesthesia induces unconsciousness affecting the entire body, while local anesthesia targets specific areas without altering consciousness.
- Administration Techniques: General anesthetics can be inhaled or administered intravenously, each with distinct pharmacokinetic properties.
Pharmacokinetics
- ADME Process: Understanding Absorption, Distribution, Metabolism, and Excretion (ADME) is critical for determining how anesthetic agents affect patients.
- Absorption: The route of administration influences bioavailability; intravenous drugs achieve 100% bioavailability immediately.
- Distribution: Drugs spread through bodily fluids and tissues post-administration.
- Metabolism & Excretion: Primarily occurs in the liver; understanding these processes aids in predicting drug elimination rates.
Pharmacodynamics
- Drug-Receptor Interaction:
- Agonists vs. Antagonists: Full agonists activate receptors fully, while partial agonists have limited activation. Neutral antagonists block receptor activity without activating them. Inverse agonists reduce baseline receptor activity.
- Dose-Response Relationship: This relationship illustrates how varying doses impact therapeutic effects and side effects.
Key Takeaways
- Understanding both pharmacokinetics and pharmacodynamics is essential for selecting appropriate anesthetic agents tailored to individual patient needs.
- The route of administration significantly affects drug absorption rates and overall effectiveness during surgical procedures.
- Knowledge of drug interactions at the receptor level informs clinical decisions regarding medication management in anesthesia practice.