Podcast
Questions and Answers
What best describes local action of a drug?
What best describes local action of a drug?
- The action is systemic and affects all organ systems.
- The action is felt throughout the entire body.
- The action is transmitted to a linked nervous system area.
- The action is only manifested at the site of application. (correct)
Which of the following processes is NOT part of the pharmacokinetics acronym ADME?
Which of the following processes is NOT part of the pharmacokinetics acronym ADME?
- Absorption
- Metabolism
- Expenditure (correct)
- Distribution
What is the primary focus of pharmacokinetics?
What is the primary focus of pharmacokinetics?
- The temporal concentration trend of a drug in the body. (correct)
- The effects of a drug at the cellular level.
- The psychological effects of drug consumption.
- The study of drug interactions.
Which of the following terms refers to the process by which a drug moves from the blood to tissues?
Which of the following terms refers to the process by which a drug moves from the blood to tissues?
Why is it important for patients to follow the therapeutic regimen?
Why is it important for patients to follow the therapeutic regimen?
What type of action extends to a whole area connected at nervous and vascular levels?
What type of action extends to a whole area connected at nervous and vascular levels?
What is the overall goal of pharmacokinetics?
What is the overall goal of pharmacokinetics?
What must occur before a drug can exert its effect in the body?
What must occur before a drug can exert its effect in the body?
Which concentration is critical in determining the therapeutic regimen?
Which concentration is critical in determining the therapeutic regimen?
How does metabolism affect a drug within pharmacokinetics?
How does metabolism affect a drug within pharmacokinetics?
What characterizes zero-order kinetics in drug transport?
What characterizes zero-order kinetics in drug transport?
What happens when the partition coefficient (PC) of a drug is much larger than 1?
What happens when the partition coefficient (PC) of a drug is much larger than 1?
In which scenario does first-order kinetics occur during drug transport?
In which scenario does first-order kinetics occur during drug transport?
Which of the following factors does NOT influence the flow of a drug across a membrane according to Fick’s Law?
Which of the following factors does NOT influence the flow of a drug across a membrane according to Fick’s Law?
What process involves the formation of vesicles for large, hydrophilic drugs?
What process involves the formation of vesicles for large, hydrophilic drugs?
How does passive diffusion of a drug proceed?
How does passive diffusion of a drug proceed?
Which factors influence the permeability of membranes for drug absorption?
Which factors influence the permeability of membranes for drug absorption?
Under what condition can a weak acid like acetylsalicylic acid more easily diffuse through a membrane?
Under what condition can a weak acid like acetylsalicylic acid more easily diffuse through a membrane?
How does binding to plasma proteins affect the penetration of drugs through membranes?
How does binding to plasma proteins affect the penetration of drugs through membranes?
What is a characteristic of transcytosis in cellular transport?
What is a characteristic of transcytosis in cellular transport?
What happens to a weak base when it is placed in an acidic bodily fluid?
What happens to a weak base when it is placed in an acidic bodily fluid?
What typically occurs when the drug concentration is greater than the saturated transporter capacity?
What typically occurs when the drug concentration is greater than the saturated transporter capacity?
Which of the following best represents a characteristic necessary for a drug to effectively cross the membrane?
Which of the following best represents a characteristic necessary for a drug to effectively cross the membrane?
Which transport mechanism always follows the concentration gradient and does not require energy?
Which transport mechanism always follows the concentration gradient and does not require energy?
Which of the following is the least permissive barrier for drug absorption?
Which of the following is the least permissive barrier for drug absorption?
What happens during receptor-mediated endocytosis?
What happens during receptor-mediated endocytosis?
In relation to drug concentration, what determines the crossing velocity from compartment 1 to compartment 2?
In relation to drug concentration, what determines the crossing velocity from compartment 1 to compartment 2?
What term describes the build-up of a higher concentration of a chemical across a cell membrane due to pH differences?
What term describes the build-up of a higher concentration of a chemical across a cell membrane due to pH differences?
What is the primary reason the blood-brain barrier (BBB) is highly impermeable?
What is the primary reason the blood-brain barrier (BBB) is highly impermeable?
Which area of the body has a more permeable barrier compared to the normal BBB?
Which area of the body has a more permeable barrier compared to the normal BBB?
What is one of the main disadvantages of the oral administration route?
What is one of the main disadvantages of the oral administration route?
Which factor directly influences the bioavailability of a drug administered orally?
Which factor directly influences the bioavailability of a drug administered orally?
What is first-pass metabolism?
What is first-pass metabolism?
What is the primary site of drug absorption when taken orally?
What is the primary site of drug absorption when taken orally?
What is the effect of carbohydrates on blood flow during drug absorption?
What is the effect of carbohydrates on blood flow during drug absorption?
How does the presence of food generally affect drug absorption after oral administration?
How does the presence of food generally affect drug absorption after oral administration?
What does selectivity refer to regarding a drug's interaction with receptors?
What does selectivity refer to regarding a drug's interaction with receptors?
Which factor is NOT important for oral bioavailability?
Which factor is NOT important for oral bioavailability?
Study Notes
Drug Action Types
- Local Action: Effects confined to the application site (e.g., local anesthetics, topical anti-inflammatories).
- Regional Action: Effects extend to the entire area connected via the nervous and vascular systems (e.g., epidural anesthesia).
- Systemic Action: Drug affects the whole organism via systemic circulation.
Pharmacokinetics Overview
- Definition: Study of drug concentration trends over time in the body.
- Processes Involved:
- Absorption: Drug movement from administration site to bloodstream.
- Distribution: Drug movement from blood to tissues.
- Metabolism: Biotransformation processes that inactivate drugs for elimination.
- Excretion: Elimination of drugs from the body.
- Goal: Optimize therapy by predicting drug concentration at action sites.
Membrane Crossing Mechanisms
- Drug Crossing Mechanisms:
- Passive Diffusion: Drug moves along concentration gradients without energy.
- Transport Mediated: Channels and carriers facilitate drug movement.
- Endocytosis/Exocytosis: Vesicle formation for large, hydrophilic drugs.
Partition Coefficient (PC)
- Definition: Ratio of drug concentration in oil vs. water; indicates lipophilicity.
- PC Interpretation:
- PC > 1: Compound is lipophilic; easy membrane diffusion.
- PC close to 0: Compound is hydrophilic; difficult to cross membranes.
- Factors Affecting PC: Metabolism, pH, and pKa of drug.
Henderson-Hasselbalch Equation
- Purpose: Determines the permeability of charged molecules across membranes.
- Ion Trapping: Weak acids/bases can become charged in different pH environments, affecting their permeability.
Fick's Law
- Principles:
- Drug crossing is favored by PC near 1.
- Thinner membranes enhance diffusion; larger surfaces favor it.
- Flow is affected by concentration differences across compartments.
Kinetics of Drug Transport
- Passive Diffusion Kinetics: Follows first-order kinetics where diffusion rate decreases until equilibrium.
- Active Transport: Involves zero-order kinetics at saturation; constant velocity regardless of concentration.
Administration Routes
- Enteral: Oral, sublingual, rectal routes; drugs pass through gastrointestinal tract.
- Parenteral: Intravascular (IV), intramuscular, cutaneous, and other routes bypass GI tract.
Oral Administration
- Key Steps for Oral Drugs:
- Must dissolve in the digestive tract.
- Cross gastrointestinal mucosa to enter portal circulation, bypassing hepatic filtering.
- Bioavailability Factors: Solubility, surface area, vascularization, and organ functional state influence how much drug reaches systemic circulation.
Blood-Brain Barrier (BBB)
- Characteristics: Highly impermeable due to tight junctions and astrocyte end-feet.
- Factors Affecting Drug Passage:
- Binding to plasma proteins.
- Ionization: Only non-ionized drugs can cross.
- Lipophilicity: Highly lipophilic drugs penetrate better.
- Transport Mechanisms: Specialized transporters aid larger molecules' crossing.
Specific Flow and Permeability
- Specific Flow: Indicates membrane permeability; higher specific flow accelerates absorption.
- Barrier Features: Vascular permeability varies by tissue type; highly vascular areas may still be impermeable.
Key Definitions
- Selectivity: Ability of a drug to bind preferentially to one receptor subtype over others.
- Specificity: Degree to which a drug interacts with a particular receptor.
Conclusion
- Understanding pharmacokinetics, membrane dynamics, and administration routes is crucial for drug efficacy and patient therapy optimization.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the different types of drug actions based on their effects on the body. Learn about local, regional, and systemic actions, and how these classifications influence medical treatment strategies. Ideal for students in pharmacology or medicine.
