Pharmacology Week #2 (Test 1) UPDATED ACTUAL
Questions and CORRECT Answers
What is pharmacokinetics? Pharmacokinetics is the study of how the body handles a drug over a period of
time.
What does it include? (4)
This includes absorption, distribution, biotransformation, and excretion
These factors effect what?
These factors affect a patient's response to drug therapy.
List the four factors that are involved when talking 1. Absorption: Getting the drug into the body.
about pharmacokinetics of a drug, along with a 2. Distribution: How the drug moves around in the body.
definition for each. 3. Elimination: How to body gets rid of chemicals.
4. Metabolism: How the body chemically changes drugs to make them more
water soluble or inactive.
What does absorption involve? Getting the drug from the Gut into Systemic Circulation.
Absorption is faster with what? Faster on an empty stomach (especially if the drug is non-fat soluble), slower
with food in stomach.
How long does absorption typically take for immediate
release drugs? Usually range of 20 minutes to an hour for Immediate Release drugs.
How does most absorption take place? What does this Most absorption takes place via passive diffusion across a semi-permeable
mean? (3) membrane. This means the molecules must be relatively small, neutral charge,
and fairly lipid soluble.
Where does most absorption actually take place? In the small intestine.
,Based on the concept of passive diffusion, explain how 1. Drugs will go down their concentration gradient, from high to low
drugs are absorbed. (3) concentration, until it's even on both sides.
2. The more drug on one side of the bilayer, the faster it will cross (called
concentration dependent transfer). As the concentration gradient on either
side of the membrane becomes less and less, the rate of passive diffusion will
also get less and less.
3. Also the more drug that is given, the faster it is going to get there.
In order for a drug to be absorbed via passive diffusion 1. Must be small.
in either the stomach or the small intestine, what three 2. Cannot have an electrical charge.
characteristics must it have? 3. Must be fat soluble, or lipophilic.
Although most drugs are transported across the cell If the molecule is lipophilic, too large, or has a charge, then is is transported via
membrane via passive diffusion, how else can they active transport, or a carrier-mediated mechanism.
cross the phospholipid bilayer?
What direction do transporter proteins transport From the intestinal lumen to the interstitial space.
drugs?
P glycoprotein. This is a genetic defect some individuals have where instead of
What is a genetic defect that effects this process? pumping drugs / toxins out of the intestinal lumen into the interstitial space, the
drugs are pumped from the interstitial space back into the intestinal lumen,
increasing toxicity.
What does the cell membrane consist of? Consists of a lipid bilayer with protein molecules irregularly dispersed
throughout
What can a protein molecule act as? (3) 1. A carrier enzyme
2. A receptor
3. An antigenic site (a mechanism by which infectious agents alter their surface
proteins to avoid the host's immune system).
What type of drugs can pass through the phospholipid Lipid-soluble drugs can pass through the lipid membrane, but water-soluble
membrane? drugs cannot
Water-soluble substances, such as urea, alcohol, electrolytes, and water, must
enter the cell through membrane pores.
Where does absorption begin? Absorption begins at the site of administration.
The rate and extent of absorption depends on what 1. Dosage
three factors?
2. Dosage form
3. Route of administration
What are two other factors that influence absorption? 1. The nature / thickness of the absorption surface. If a drug must only pass
through a single layer of cells (intestinal epithelium) transport will be much
faster, compared to if it must pass through several layers (skin).
2. The surface area. The greater the surface area of the absorbing site, the
greater the absorption and the more rapid the drug effect. The small intestine
offers the largest surface area, due to the presence of villi / microvilli.
The stomach has a relatively small absorption surface area
, How does blood flow effect absorption? A rich blood supply enhances absorption (sublingual route), and a poor blood
supply delays absorption (subcutaneous route).
Ex. (2)
Ex. A patient in shock may not respond to IM administration, because
diminished circulation decreases absorption.
Ex. Also why nitroglycerine is given sublingually, in order to increase the rate of
absorption.
What delivery system immediately places the drug into IV administration immediately places the drug in the circulatory system. It is
the circulatory system? completely absorbed and must be delivered to target tissue
How does solubility effect absorption? The more soluble the drug, the more rapidly it is absorbed.
Ex. Ex. Tylenol pill will longer to break down than a liquid capsule.
How does the pH of the drug environment effect In order to increase the likelihood of drug absorption, it needs to have a
absorption? neutral charge.
In solution, what do most drugs exist as? In solution, many drugs exist in an ionized (charged)and un-ionized
(uncharged) form.
The extent of this depends on what? (3)
How and to what extent a drug ionizes depends on:
1. Whether it is an acid or a base
2. Its relative strength
3. Measure of this degree of dissociation is referred to by the pKa
If an un-ionized drug is lipid soluble, then it will do If an un-ionized drug is lipid-soluble, then it readily diffuses across the cell
what? membrane.
Ex. Ex. An acidic drug (e.g., aspirin) is relatively un-dissociated (un-ionized) in an
acidic environment such as the stomach
What is the pKa? The pKa is a quantitative measure of the strength of a particular acid in
solution. The lower the pKa (esp if negative) the stronger the acid (or the lower
the pH).
What will happen to a weak acid drug in basic media? The drug will dissociate into two charged particles, now making it so it cannot
cross the phospholipid bilayer without a protein transporter.
What is the relationship between breastmilk and Breastmilk is more acidic than the blood. So, basic drugs will pick up charges in
blood?????????? DOUBLE CHECK!!!! the acidic breastmilk, and now they cannot leave the breast, 2/2 obtaining this
charge and now not being able to cross the membrane (because the drug is
no longer unionized).
When tends to happen when drugs are administered in Drugs administered in high concentrations tend to be absorbed more rapidly
high concentrations? than those administered in low concentrations.
Questions and CORRECT Answers
What is pharmacokinetics? Pharmacokinetics is the study of how the body handles a drug over a period of
time.
What does it include? (4)
This includes absorption, distribution, biotransformation, and excretion
These factors effect what?
These factors affect a patient's response to drug therapy.
List the four factors that are involved when talking 1. Absorption: Getting the drug into the body.
about pharmacokinetics of a drug, along with a 2. Distribution: How the drug moves around in the body.
definition for each. 3. Elimination: How to body gets rid of chemicals.
4. Metabolism: How the body chemically changes drugs to make them more
water soluble or inactive.
What does absorption involve? Getting the drug from the Gut into Systemic Circulation.
Absorption is faster with what? Faster on an empty stomach (especially if the drug is non-fat soluble), slower
with food in stomach.
How long does absorption typically take for immediate
release drugs? Usually range of 20 minutes to an hour for Immediate Release drugs.
How does most absorption take place? What does this Most absorption takes place via passive diffusion across a semi-permeable
mean? (3) membrane. This means the molecules must be relatively small, neutral charge,
and fairly lipid soluble.
Where does most absorption actually take place? In the small intestine.
,Based on the concept of passive diffusion, explain how 1. Drugs will go down their concentration gradient, from high to low
drugs are absorbed. (3) concentration, until it's even on both sides.
2. The more drug on one side of the bilayer, the faster it will cross (called
concentration dependent transfer). As the concentration gradient on either
side of the membrane becomes less and less, the rate of passive diffusion will
also get less and less.
3. Also the more drug that is given, the faster it is going to get there.
In order for a drug to be absorbed via passive diffusion 1. Must be small.
in either the stomach or the small intestine, what three 2. Cannot have an electrical charge.
characteristics must it have? 3. Must be fat soluble, or lipophilic.
Although most drugs are transported across the cell If the molecule is lipophilic, too large, or has a charge, then is is transported via
membrane via passive diffusion, how else can they active transport, or a carrier-mediated mechanism.
cross the phospholipid bilayer?
What direction do transporter proteins transport From the intestinal lumen to the interstitial space.
drugs?
P glycoprotein. This is a genetic defect some individuals have where instead of
What is a genetic defect that effects this process? pumping drugs / toxins out of the intestinal lumen into the interstitial space, the
drugs are pumped from the interstitial space back into the intestinal lumen,
increasing toxicity.
What does the cell membrane consist of? Consists of a lipid bilayer with protein molecules irregularly dispersed
throughout
What can a protein molecule act as? (3) 1. A carrier enzyme
2. A receptor
3. An antigenic site (a mechanism by which infectious agents alter their surface
proteins to avoid the host's immune system).
What type of drugs can pass through the phospholipid Lipid-soluble drugs can pass through the lipid membrane, but water-soluble
membrane? drugs cannot
Water-soluble substances, such as urea, alcohol, electrolytes, and water, must
enter the cell through membrane pores.
Where does absorption begin? Absorption begins at the site of administration.
The rate and extent of absorption depends on what 1. Dosage
three factors?
2. Dosage form
3. Route of administration
What are two other factors that influence absorption? 1. The nature / thickness of the absorption surface. If a drug must only pass
through a single layer of cells (intestinal epithelium) transport will be much
faster, compared to if it must pass through several layers (skin).
2. The surface area. The greater the surface area of the absorbing site, the
greater the absorption and the more rapid the drug effect. The small intestine
offers the largest surface area, due to the presence of villi / microvilli.
The stomach has a relatively small absorption surface area
, How does blood flow effect absorption? A rich blood supply enhances absorption (sublingual route), and a poor blood
supply delays absorption (subcutaneous route).
Ex. (2)
Ex. A patient in shock may not respond to IM administration, because
diminished circulation decreases absorption.
Ex. Also why nitroglycerine is given sublingually, in order to increase the rate of
absorption.
What delivery system immediately places the drug into IV administration immediately places the drug in the circulatory system. It is
the circulatory system? completely absorbed and must be delivered to target tissue
How does solubility effect absorption? The more soluble the drug, the more rapidly it is absorbed.
Ex. Ex. Tylenol pill will longer to break down than a liquid capsule.
How does the pH of the drug environment effect In order to increase the likelihood of drug absorption, it needs to have a
absorption? neutral charge.
In solution, what do most drugs exist as? In solution, many drugs exist in an ionized (charged)and un-ionized
(uncharged) form.
The extent of this depends on what? (3)
How and to what extent a drug ionizes depends on:
1. Whether it is an acid or a base
2. Its relative strength
3. Measure of this degree of dissociation is referred to by the pKa
If an un-ionized drug is lipid soluble, then it will do If an un-ionized drug is lipid-soluble, then it readily diffuses across the cell
what? membrane.
Ex. Ex. An acidic drug (e.g., aspirin) is relatively un-dissociated (un-ionized) in an
acidic environment such as the stomach
What is the pKa? The pKa is a quantitative measure of the strength of a particular acid in
solution. The lower the pKa (esp if negative) the stronger the acid (or the lower
the pH).
What will happen to a weak acid drug in basic media? The drug will dissociate into two charged particles, now making it so it cannot
cross the phospholipid bilayer without a protein transporter.
What is the relationship between breastmilk and Breastmilk is more acidic than the blood. So, basic drugs will pick up charges in
blood?????????? DOUBLE CHECK!!!! the acidic breastmilk, and now they cannot leave the breast, 2/2 obtaining this
charge and now not being able to cross the membrane (because the drug is
no longer unionized).
When tends to happen when drugs are administered in Drugs administered in high concentrations tend to be absorbed more rapidly
high concentrations? than those administered in low concentrations.
