Pharmacokinetics I absorption & distribution of drugs Flashcards
What is drug absorption?
The process by which a drug enters the bloodstream from its site of administration.
How does pH affect drug ionization?
The pH of the environment can influence the ionization state of a drug, affecting its solubility and absorption.
True or False: Weak acids are more ionized in alkaline environments.
True.
Fill in the blank: The Henderson-Hasselbalch equation helps to predict the degree of ________ of a drug at a given pH.
ionization
What is the Henderson-Hasselbalch equation?
A mathematical formula that relates the pH of a solution to the pKa of an acid and the ratio of the ionized and un-ionized forms of the drug.
Which type of drugs are more likely to be absorbed in the stomach?
Weak acids.
True or False: The ionization of a drug affects its permeability across biological membranes.
True.
What does pKa represent?
The pH at which half of the drug is ionized and half is in its non-ionized form.
Multiple Choice: Which factor does NOT affect drug absorption? A) pH B) Blood flow C) Molecular weight D) Drug color
D) Drug color.
What is the primary site of drug absorption in the body?
The small intestine.
Fill in the blank: Drugs that are ________ are typically better absorbed in acidic environments.
non-ionized
True or False: Ionized drugs are generally more soluble in lipids.
False.
What happens to weak bases in acidic environments?
They become more ionized, which can decrease their absorption.
Multiple Choice: What is the effect of increased blood flow on drug absorption? A) Decrease absorption B) No effect C) Increase absorption D) It depends on the drug
C) Increase absorption.
What role do transport proteins play in drug absorption?
They facilitate the movement of drugs across cell membranes.
Fill in the blank: The ________ of a drug can influence its absorption by altering its solubility.
formulation
True or False: Food can affect drug absorption by changing gastric pH.
True.
What is the effect of a drug being highly ionized on its absorption?
It is likely to have poor absorption due to reduced lipid solubility.
What does ‘first-pass metabolism’ refer to?
The initial metabolism of a drug in the liver before it reaches systemic circulation.
Multiple Choice: Which of the following is a factor that can influence drug absorption? A) Age B) Gender C) Disease state D) All of the above
D) All of the above.
What is the primary reason for the use of enteric coatings on tablets?
To protect the drug from stomach acid and ensure it is absorbed in the intestine.
Fill in the blank: The ________ of a drug affects its ability to cross cell membranes.
lipophilicity
True or False: The solubility of a drug does not impact its absorption.
False.
What is the relationship between drug concentration and absorption rate?
Generally, a higher concentration of drug increases the absorption rate.
What is the definition of the oral route of administration?
The oral route of administration involves taking medication by mouth, allowing it to be absorbed through the gastrointestinal tract.
True or False: The oral route is the most common route of drug administration.
True
What is one advantage of oral administration?
It is non-invasive and generally easy for patients to self-administer.
What is one disadvantage of oral administration?
It may have variable absorption due to food interactions and gastrointestinal conditions.
Fill in the blank: The ______ route of administration involves injecting medication directly into the bloodstream.
intravenous
What is a key advantage of intravenous administration?
It provides rapid onset of action and precise control over drug levels in the bloodstream.
What is a major disadvantage of intravenous administration?
It requires specialized skills for administration and carries a risk of infection.
Which route of administration involves inhaling medication directly into the lungs?
Inhalation route
True or False: Inhalation administration can provide rapid effects for respiratory conditions.
True
What is one advantage of the transdermal route of administration?
It allows for sustained release of medication over an extended period.
What is a disadvantage of transdermal administration?
It is limited to drugs that can penetrate the skin effectively.
What is the definition of the subcutaneous route of administration?
The subcutaneous route involves injecting medication into the tissue layer between the skin and muscle.
What is one advantage of subcutaneous administration?
It is relatively easy to perform and can be self-administered.
What is a disadvantage of subcutaneous administration?
Absorption can be slow and variable compared to other routes.
Fill in the blank: The ______ route of administration delivers medication directly into the muscle.
intramuscular
What is one advantage of intramuscular administration?
It allows for larger volumes of medication to be injected compared to subcutaneous administration.
What is a disadvantage of intramuscular administration?
It may cause pain and discomfort at the injection site.
Which route of administration involves placing medication under the tongue?
Sublingual route
True or False: The sublingual route allows for rapid absorption into the bloodstream.
True
What is one advantage of the rectal route of administration?
It can be useful for patients who are vomiting or unable to take medications orally.
What is a disadvantage of rectal administration?
It may be uncomfortable for some patients and has variable absorption.
What is the definition of the topical route of administration?
The topical route involves applying medication directly to the skin or mucous membranes.
What is one advantage of topical administration?
It targets local effects and minimizes systemic side effects.
What is a disadvantage of topical administration?
It may not be suitable for deeper tissue conditions.
Fill in the blank: The ______ route is often used for vaccines and involves administration into the skin.
intradermal
What is one unique characteristic of the intradermal route?
It allows for a small volume of medication to be administered with a targeted local effect.
What is drug bioavailability?
Drug bioavailability is the fraction of an administered dose of a drug that reaches the systemic circulation in an unchanged form.
True or False: Bioavailability is only relevant for intravenous drug administration.
False.
What are the two primary routes of drug administration?
Enteral and parenteral.
Fill in the blank: The bioavailability of a drug is influenced by its ________ and ________ properties.
pharmacokinetic, pharmacodynamic
Which factor can significantly affect drug absorption in the gastrointestinal tract?
Gastric pH.
What is the term for the first-pass metabolism?
The metabolism of a drug by the liver before it reaches systemic circulation.
True or False: The formulation of a drug can affect its bioavailability.
True.
What is the significance of solubility in drug bioavailability?
Higher solubility can enhance absorption and increase bioavailability.
List one physiological factor that affects drug bioavailability.
Gastrointestinal motility.
What is the impact of food on drug bioavailability?
Food can enhance or inhibit the absorption of certain drugs.
What is the relationship between drug formulation and bioavailability?
Different formulations (e.g., tablets, capsules, liquids) can have varying bioavailability.
True or False: All drugs have 100% bioavailability when administered intravenously.
True.
What does a bioavailability of 0.5 mean?
It means that 50% of the administered dose reaches systemic circulation in an unchanged form.
Fill in the blank: The presence of ________ can alter drug absorption due to changes in gastrointestinal pH.
antacids
What is the role of drug transporters in bioavailability?
Drug transporters can facilitate or hinder the absorption of drugs in the intestines.
Which factor can influence the bioavailability of orally administered drugs?
Presence of other medications.
True or False: Age can affect drug bioavailability.
True.
What does the term ‘bioequivalence’ refer to?
The comparison of two drugs that have the same bioavailability and pharmacokinetic profiles.
What is the effect of liver function on bioavailability?
Impaired liver function can increase bioavailability due to reduced first-pass metabolism.
List one drug characteristic that affects bioavailability.
Molecular size.
What is a common method to measure bioavailability?
Plasma concentration-time curve analysis.
True or False: Bioavailability is a fixed value for every drug.
False.
What does the term ‘absolute bioavailability’ mean?
The comparison of the bioavailability of a drug administered by a non-intravenous route to that of the same drug administered intravenously.
Fill in the blank: Drug ________ can affect how much of the drug is absorbed into the bloodstream.
stability
What role does the gut microbiome play in drug bioavailability?
The gut microbiome can metabolize drugs and affect their absorption.
What is bioavailability?
Bioavailability is the fraction of an administered dose of a drug that reaches the systemic circulation in an unchanged form.
True or False: The route of administration significantly affects the bioavailability of a drug.
True
Fill in the blank: The __________ route of administration generally has the highest bioavailability.
intravenous
Which route of administration typically has lower bioavailability: oral or intravenous?
oral
What factors influence the bioavailability of orally administered drugs?
Factors include drug formulation, gastrointestinal pH, presence of food, and first-pass metabolism.
Multiple Choice: Which of the following routes has the lowest bioavailability? A) Oral B) Sublingual C) Intravenous D) Intramuscular
A) Oral
What is first-pass metabolism?
First-pass metabolism is the process by which a drug is metabolized at specific sites in the body, primarily the liver, before reaching systemic circulation.
True or False: Sublingual administration bypasses first-pass metabolism.
True
Fill in the blank: __________ administration allows for rapid absorption directly into the bloodstream.
Intravenous
What is the primary advantage of using intramuscular injections?
Intramuscular injections can achieve a faster onset of action compared to oral administration.
Multiple Choice: Which route of administration is typically used for vaccines? A) Oral B) Intravenous C) Subcutaneous D) Intramuscular
D) Intramuscular
What is the bioavailability of a drug administered intravenously?
The bioavailability of a drug administered intravenously is considered to be 100%.
True or False: Topical administration generally provides high systemic bioavailability.
False
Fill in the blank: The __________ route is often used for local effects, resulting in lower systemic bioavailability.
topical
What is the impact of food on oral drug bioavailability?
Food can enhance or inhibit the absorption of oral drugs, thereby affecting their bioavailability.
Multiple Choice: Which of the following is a disadvantage of oral administration? A) Easy to administer B) First-pass metabolism C) Rapid onset D) High bioavailability
B) First-pass metabolism
What does the term ‘systemic circulation’ refer to?
Systemic circulation refers to the part of the cardiovascular system that carries blood from the heart to the rest of the body and back.
True or False: Rectal administration can provide variable bioavailability.
True
Fill in the blank: Drugs administered __________ can have their absorption affected by the formulation and pH of the gastrointestinal tract.
orally
What is the significance of drug formulation in relation to bioavailability?
Drug formulation can affect the release and absorption rate of the drug, impacting its overall bioavailability.
Multiple Choice: Which route of administration is NOT typically used for immediate effects? A) Oral B) Intravenous C) Inhalation D) Topical
A) Oral
What is an example of a drug with high first-pass metabolism?
Morphine is an example of a drug with high first-pass metabolism.
True or False: Inhalation administration generally has high bioavailability.
True
Fill in the blank: The __________ route of administration is often used for rapid delivery of medication to the lungs.
inhalation
What is the effect of drug solubility on bioavailability?
Drug solubility can influence the rate and extent of absorption, thereby affecting bioavailability.
What is drug distribution?
The process by which a drug is dispersed throughout the fluids and tissues of the body.
True or False: Drug distribution is influenced solely by the drug’s chemical properties.
False
What are the primary factors that determine the rate of drug distribution?
Blood flow, tissue permeability, binding to plasma proteins, and the drug’s lipophilicity.
Fill in the blank: The ________ of a drug affects how quickly it reaches its target tissue.
rate of distribution
Multiple choice: Which factor is NOT a determinant of drug distribution? A) Blood flow B) Age C) Lipophilicity D) Molecular weight
B) Age
What role does blood flow play in drug distribution?
Increased blood flow enhances the delivery of the drug to various tissues.
True or False: Highly lipophilic drugs distribute faster than hydrophilic drugs.
True
What is the significance of plasma protein binding in drug distribution?
It affects the free concentration of the drug available for distribution to tissues.
Fill in the blank: The ________ of the tissue can affect how quickly a drug is distributed.
permeability
Multiple choice: Which type of tissue typically has the highest permeability for drug distribution? A) Muscle B) Fat C) Brain D) Skin
C) Brain
Describe how molecular size influences drug distribution.
Larger molecules may have more difficulty crossing cell membranes and therefore distribute more slowly.
True or False: Drug distribution is a passive process.
True
What is the term for the volume of distribution (Vd)?
A pharmacokinetic parameter that describes the extent to which a drug is distributed in body tissues.
Fill in the blank: The volume of distribution can help predict the ________ of a drug in the body.
concentration
Multiple choice: Which condition can alter drug distribution? A) Liver disease B) Exercise C) Temperature D) All of the above
D) All of the above
What is the blood-brain barrier’s role in drug distribution?
It restricts the passage of many drugs into the central nervous system.
True or False: Drugs that are ionized are more likely to be distributed across cell membranes.
False
What does the term ‘bioavailability’ refer to in the context of drug distribution?
The proportion of a drug that enters circulation when introduced into the body and is available for action.
Fill in the blank: Drug distribution can be influenced by ________ factors such as age and gender.
physiological
Multiple choice: Which of the following drugs would likely have a high volume of distribution? A) Warfarin B) Gentamicin C) Digoxin D) Insulin
C) Digoxin
What is the impact of tissue perfusion on drug distribution?
Poorly perfused tissues receive drugs more slowly compared to well-perfused tissues.
True or False: Drug distribution is the same in all tissues of the body.
False
What factor can increase the risk of drug accumulation in tissues?
High lipophilicity of the drug.
Fill in the blank: The ________ effect can significantly affect the distribution of drugs that undergo first-pass metabolism.
first-pass
Multiple choice: Which characteristic typically allows a drug to cross cell membranes more easily? A) High polarity B) Low lipophilicity C) Small size D) High ionization
C) Small size
What does the term ‘redistribution’ mean in pharmacology?
The process by which a drug moves from its site of action to other tissues.
What is the two compartment model in pharmacokinetics?
A pharmacokinetic model that describes the distribution of a drug in the body using two compartments: the central compartment and the peripheral compartment.
True or False: In the two compartment model, the central compartment is typically where the drug is administered.
True
What are the two compartments in the two compartment model?
The central compartment and the peripheral compartment.
Fill in the blank: The central compartment often includes the _____ and _____ where the drug is rapidly distributed.
blood, highly perfused organs
What is the primary characteristic of the peripheral compartment?
It includes tissues where the drug is distributed more slowly and may remain for a longer duration.
Multiple choice: Which factor does NOT influence drug distribution in the two compartment model?
D. The color of the drug
What is meant by ‘distribution phase’ in the two compartment model?
The phase during which the drug moves from the central compartment to the peripheral compartment.
True or False: The two compartment model can accurately predict drug behavior for all drugs.
False
What is the role of blood flow in drug distribution?
Increased blood flow enhances drug distribution to tissues.
Name a physiological factor that affects drug distribution.
Tissue permeability.
Fill in the blank: The volume of distribution is a measure of how extensively a drug is _____ throughout the body.
distributed
What is the significance of protein binding in drug distribution?
It affects the free concentration of the drug available for distribution and action.
Multiple choice: Which of the following can alter drug distribution?
C. Changes in body composition
What is the effect of lipophilicity on drug distribution?
Lipophilic drugs tend to accumulate in fatty tissues and distribute more widely.
True or False: The two compartment model assumes instantaneous distribution between compartments.
False
What is the ‘equilibrium’ in the context of the two compartment model?
The state where the concentration of the drug in both compartments is stable over time.
Fill in the blank: The term ‘clearance’ refers to the rate at which a drug is _____ from the body.
eliminated
Name one clinical application of the two compartment model.
Determining appropriate dosing regimens for drugs.
What does the term ‘half-life’ refer to in pharmacokinetics?
The time it takes for the concentration of the drug in the body to reduce by half.
Multiple choice: In the two compartment model, which phase typically has a shorter half-life?
A. Distribution phase
What is the impact of age on drug distribution?
Age can alter body composition and organ function, affecting drug distribution.
Fill in the blank: Drugs that are highly _____ bound may have a reduced volume of distribution.
protein
True or False: The two compartment model is useful for drugs that exhibit linear pharmacokinetics.
True
What is the primary limitation of the two compartment model?
It may oversimplify the complex distribution processes of some drugs.
