Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pharmacology 1 > ADME > Flashcards

ADME Flashcards

1
Q

First order kinetic processes

A

Remove a constant proportion (percentage) of drug

  • applies to most oral and extra-vascular administrations
  • elimination rate constant primarily determines terminal drug concentrations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Drug disposition is composed of

A

Absorption
Distribution
Metabolism
Excretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Biotransport

A

Movement of drug across biological membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Filtration

A

Open channels allow small molecules to move

  • bulk flow
  • ex: filtration of drugs at the glomerulus
  • water flows freely thru pores
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Facilitated diffusion

A

Passive diffusion that utilizes carrier protein for the solute to cross the membrane (carries substances that would not normally cross)

  • uses no energy
  • follows concentration gradient
  • can become saturated
  • ex: glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Active transport

A

Uses carrier protein to move drug against a concentration gradient
- relies on direct expenditure of ATP as energy source

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Pinocytosis

A

Type of endocytosis (cell drinking) used to move very large molecules in a solution inside the cell
- takes in dissolved water soluble molecules that would not normally enter the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Passive diffusion

A

Most common method of biotransport, drugs must pass 3 interfaces (phospholipid bilayer)

  • outer water-lipid interface
  • lipid membrane
  • inner water-lipid interface
  • drugs must be water soluble enough to enter aqueous solutions, but lipid soluble enough to traverse lipid membrane*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What allows a substance to cross the lipid membrane?

A

Lipid solubility

all drugs are water soluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What attributes must a drug have for biotransport by passive diffusion?

A
  • small: diffusion coefficient inversely related to sq root of MW
  • unbound (free) drugs
  • lipid solubility
  • unionized
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What effect does protein binding of a drug have on its ability to passively diffuse?

A

Most drugs are nonspecifically bound to proteins (acidic drugs bind to albumin, basic drugs bind to glyco/lipoproteins)

  • weak (reversible) binding via electrostatic interactions, van der Waals, hydrogen binding
  • drug-protein complex is too large to allow for passive diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Regarding drug binding, is bound, unbound (free), or both in an active state to interact with receptors?

A

Unbound*

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fick’s Law of diffusion

A 
dQ/dt = rate of diffusion
A = surface area of membrane
h = membrane thickness
D = diffusion coefficient
Characteristics of solute (drug): 
Kp = partition coefficient
C1-C2 = concentration difference for solute
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Rate of diffusion characteristics

A
  • larger the surface area = greater rate of diffusion
  • thicker the membrane = slower rate of diffusion
  • diffusion coefficient = characteristics of membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Lipid-solubility

A

Oil:water partition coefficient

- greater partition coefficient, higher the lipid-solubility of the drug, and the greater its diffusion across membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Most drugs are ______

A

Weak acids or weak bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Unionized characteristic

A

Ionized particles attract water –> cannot pass thru lipid bilayer
- fraction of drug that is unionized depends on chemical nature, pKa, and local pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Brodie pH partition hypothesis

A

Uses Henderson-Hasselback equation to predict drug concentration across a membrane

  • acidic drugs concentrate on more basic side of membrane (outside cell)
  • basic drugs concentrate on more acidic side of membrane (inside cell)
  • need to know the pKa and the pH)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Clinical application of Brodie pH partition hypothesis

A

Basic drugs penetrate intracellularly better than acidic drugs
- ion trapping can be used to enhance renal elimination of a drug or toxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

pKa

A

pH at which half of a molecule is in its ionized form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Bioavailability versus bioequivalence

A

Bioavailability: fraction of drug absorbed (F)
Bioequivalence: refers to extent of absorption (bioavailability) and rate of absorption

22
Q

A drug is considered to be absorbed when it enters _________

A

Central circulation

23
Q

Generic formulations must show _______ to pioneer product in order to be approved

A

Bioequivalence

24
Q

First pass effect

A

Removal of the drug by the liver before it enters the central circulation after oral dosing

25
____ and _____ administration may bypass the first effect
Rectal and buccal
26
What is enterohepatic recirculation and how does it affect bioavailability?
Drug already in the central circulation is removed by the liver but then reenters the circulation - falsely increases value of F to greater than 100% - give activated charcoal to prevent drugs/toxins from being reabsorbed
27
Diffusion limited distribution
Distribution is diffusion (permeability) rate limited when: - drug is ionized and polar (water soluble), such that physiological barriers restrict the diffusion of such drugs into the cell - most drugs
28
Perfusion limited distribution
Perfusion rate is the volume of blood that flows per unit time per unit volume of the tissue (ml/min per kg of tissue) - greater blood flow = faster distribution - extent to which a drug is distributed in a particular tissue depends on the size of the tissue and the tissue blood partition coefficient of the drug
29
Distribution is perfusion rate limited when
- drug is highly lipophilic | - drug is easily diffused through highly permeable membrane (capillaries, muscles)
30
Restricted vascular space (category 1)
Most restrictive - can not pass thru endothelium - drugs bound to blood constituents (ex: protein bound portion of drug) - rare (ex: hetastarch)
31
Restricted to extracellular space (category 2)
Free portion of drug with moderate protein binding able to pass thru endothelium - limited lipid solubility (primarily water soluble) - highly ionized - ex: penicillin, does not cross inside cell, but can move into extracellular fluid
32
Category 3
Crosses most cell membranes and tissue barriers - moves into WBC, overcomes blood-placenta, blood-milk, blood-prostate barriers - free portion of drugs with moderate protein binding - moderate lipid solubility - unionized drug (ion trapped, as tissue pH is acidic vs plasma)
33
Category 4
Crosses all barriers - blood brain, blood aqueous humor, blood testicular barriers - highly lipid soluble, low protein binding, non ionized
34
How do neonates differ from adults relative to percentage of body water and how might this affect the dose of a water-soluble drug given to a neonate
Neonates have a larger percentage of body water - larger Vd for drugs that distribute primarily to extracellular space (cat 2 distribution) - lower albumin --> lower protein binding and greater distribution with greater excretion (unbound drug)
35
How effective is the blood-placental barrier against penetration of most drugs?
No barrier! | - exception: heparin
36
Storage sites for drugs
- fat - bone: chelation to calcium, or active transport using calcium transporter - stored drug is biologically inactive until mobilized
37
How do lipid soluble drugs differ from water soluble drugs regarding absorption and excretion?
Lipophilic: readily absorbed/stored Hydrophilic: readily excreted
38
Major routes of elimination
``` Kidney - filtration, secretion, reabsorption - pH influence Liver - digestive tract (feces) ```
39
Urine and feces are ________
Aqueous media | - lipophilic agents cannot partition into urine or feces and cannot be excreted (bioaccumulation)
40
____ has a large influence on reabsorption
pH
41
Minor routes of elimination
- respiratory tract (major route for volatile anesthetics) | - tears, sweat, milk
42
Which domestic animals are born with renal function near adult levels?
Foals and ruminants | - GFR adult at 2 days, secretion adult at 2-4 days
43
Which domestic animals are born with hepatic function near adult levels?
Foals | - rapid hepatic metabolic development occurs in the first 3 days of life
44
What is biotransformation
Metabolism - chemical alteration of molecule - tissues: liver most active, kidney, skin, intestine, adrenal are moderately active - enzyme-mediated (protein, chemical catalyst, lowers activation energy for rxn)
45
Cytochrome P450
Enzyme family with broad substrate specificities - most significant of all drug oxidation reactions - important in detoxification of many compounds - can cause bioactivation
46
In what organ does biotransformation primarily occur?
Liver
47
Does biotransformation always inactivate a drug?
No, could result in no change in toxicity or result in greater toxicity
48
Phase 1 of biotransformation rxn
Nonsynthetic reaction - adds or uncovers a reactive group - makes molecule more chemically reactive, metabolite can be same, less, or more active - more likely to undergo phase 2 metabolism - oxidation or hydrolysis
49
Phase 2 of biotransformation rxn
Synthetic reaction - adds an endogenous ligand - makes more polar and water soluble, and usually detoxifies - ligand interacts with reactive group and metabolite is inactive (rare exceptions) - conjugation reactions
50
Cats are deficient in what enzyme system involved in biotransformation? State an example where this deficit makes cats more susceptible to drug toxicity
Glucuronyl transferase - metabolism of many drugs altered, leading to toxicity - ex: acetaminophen toxicity, if body has enough glutathione then body is safe, if not intermediates build up and covalently bind leading to cell death
51
Enzyme inhibitor
Decreases activity of metabolic enzymes, thereby decreasing the rate of metabolism of other drugs - immediate onset due to chemical reaction
52
Enzyme inducer
Increases the amount of enzymes available for metabolism, thereby increasing the rate of metabolism of itself (autoinduction) or other drugs (induction) - requires several weeks

Pharmacology 1 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions