Questions and Answers
What is the first phase of drug action responsible for the breakdown of drugs into smaller parts?
During which phase do drugs need to be in solution to be absorbed by the body?
Which process describes the time it takes for a drug to disintegrate and dissolve for absorption?
What is the second phase of the Pharmaceutic Phase that involves breaking down the drug into even smaller particles?
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Which phase follows the Pharmaceutic Phase in the drug action process?
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Which factor increases drug absorption in acidic media?
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What is the main concern with enteric coated drugs?
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How does the presence of food affect the dissolution and absorption of drugs?
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What does bioavailability refer to in pharmacodynamics?
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At what pH range does normal gastric acid operate?
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What is the main characteristic of facilitated diffusion?
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Which transport mechanism involves the engulfing of drug particles by cells?
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What role do transporters play in drug distribution in the body?
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What effect does protein binding have on a drug's tissue penetration?
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Which statement accurately describes active transport?
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What is the primary purpose of excipients in drug formulations?
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Which of the following factors primarily affects the rate of drug dissolution?
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In which phase of drug action is the effectiveness and stability of the delivery system maintained?
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What is a key difference between liquid and solid drugs in terms of absorption?
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Which phase of drug action involves the actual therapeutic effects of the drug?
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What role do excipients play in the identification of drug products?
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How do fillers in tablets affect drug formulation?
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What aspect of gastric pH is important for drug dissolution?
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What is the effect of lipid solubility on the absorption of a drug?
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Which factor contributes significantly to the rate of drug absorption?
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How does the degree of ionization affect drug absorption?
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What is the relationship between chemical stability and drug absorption?
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What role does blood flow to the absorbing site play in drug absorption?
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Which of the following statements about drug solubility is correct?
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What is meant by the lipid to water partition coefficient in drug absorption?
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Which statement is true regarding passive transport mechanisms for drug absorption?
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What is the impact of drug particle size on absorption?
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Study Notes
Introduction to Pharmacokinetics
- Pharmacokinetics involves drug movement and processing within the body.
- Understanding encompasses three main phases: Pharmaceutic, Pharmacokinetic, and Pharmacodynamic.
Pharmaceutic Phase
- First phase where drug disintegration occurs in the gastrointestinal (GI) tract.
- Necessary for the drug to be in solution for absorption.
- Two key processes:
- Disintegration: Breakdown of the drug into smaller particles.
- Dissolution: Further breakdown into a liquid form for faster absorption.
- Tablets comprise not just drugs but also excipients (fillers and inert substances) to:
- Ensure proper size and shape.
- Enhance dissolution and stability.
Factors Affecting Dissolution Rate in the Pharmaceutic Phase
- Form of drug: Liquid forms are absorbed more rapidly than solids.
- Gastric pH: Acidic environments enhance disintegration; normal pH ranges from 1.5 to 3.5.
- Age: Young children and elderly individuals have increased pH, potentially reducing absorption.
- Enteric-coated drugs only disintegrate in alkaline environments, suitable for intestinal absorption.
- Food presence can interfere with dissolution or enhance absorption.
Pharmacokinetic Phase
- Involves absorption into the bloodstream post-administration.
- Majority (80%) of drugs are administered enterally (by mouth).
- Key components influencing bioavailability:
- Blood flow to absorption sites.
- Surface area available for absorption.
- Drug solubility: Water-soluble drugs are absorbed slower but stay longer in circulation; fat-soluble drugs are absorbed more quickly into fatty tissues.
- Chemical stability and degree of ionization impact absorption rates.
Mechanisms of Drug Transportation
-
Passive Transport:
- Diffusion: Movement across cell membranes from high to low concentration.
- Facilitated Diffusion: Requires a carrier protein, not energy-dependent, allows for rapid penetration of low lipid-solubility molecules like glucose.
-
Pinocytosis:
- Engulfing of drug particles by cells through vesicles.
-
Active Transport:
- Requires energy to move drugs against concentration gradients, often at specific sites in the small intestine.
Distribution of Drugs
- Refers to the process where drugs move from circulation to tissues.
- Transporters are vital for crossing biological barriers; many drugs target transporters.
- Key factors affecting distribution include:
- Size of the organ and tissue.
- Protein binding affinity: Minimally bound drugs penetrate tissues better but are excreted faster than highly bound counterparts.
Summary
- Pharmacokinetics consists of multiple phases that define how a drug behaves once administered.
- Understanding these processes is critical for effective drug therapy and patient management in nursing and medical practice.
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Description
This quiz covers the fundamental concepts of pharmacokinetics and its three phases: pharmaceutic, pharmacokinetic, and pharmacodynamic. Participants will learn how drugs interact with the body and the processes they undergo once administered. Enhance your understanding of drug action and its implications in nursing practice.
