Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > General Principles Of Pharmacokinetics > Flashcards

General Principles Of Pharmacokinetics Flashcards

1
Q

Knowledge of pharmockinetic data about a drag tells us

A

What does to give
How often to give it
How to change the dose in medical conditions
How some drug interactions occur
Design of new drugs

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

Effective concentration is a function of

A

Dose
Absorption
Distribution
Elimination (metabolism and excretion)

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

Absorption from where to where

A

Extravascular to systemic circulation

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

Distribution from where to where

A

Bloodstream to body tissues

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

Metabolism occur in

A

Liver
gastrointestinal tract wall
Lung
Blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Excretion occur in

A

Kidney
Bile
Expired air

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

Pharmokinetic parameters

A

Absorption- Bioavailability (F)
Distribution- Volume of Distribution
Metabolism- Elimination and Clearence
Excretion

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

Factors effecting drug absorption

A

Chemical and physical properties of the drug
ROA
Patients physiological variables
Drug-drug or food interactions
Drug and drug delivery
Mechanism of transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Physiological properties that effect the drug absorption

A

Age
Sex
Genetic
Malabsorptive states
Lack of specific receptors needed for absorption
GI motility
Area of absorbing surface
Compliance of patient
Drug interactions
Site of drug administration
Blood flow at the absorption site
PH at the absorption site
Inactivation of drug in gut or liver
Food

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

Which properties effect drug absorption as a chemical and physical substance

A

Solubility— Partition coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Partition Coefficient

A

Solubility of the molecule in a lipid solvent relative to its solubility in water or physiologic buffer
Higher PC— HIGHER DIFFUSION RATE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an Ion-trap?

A

At equilibrium, the total concentration of the drug will be different in each compartment.
Trap the toxins in its ionized form in the urine where it can be excreted.

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

Which type of drugs absorbed best?

A

Lips-soluble
Non-ionized
Small molecular weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why do we need to take the drugs with the water?

A

Accelerate gastric emptying providing exposure to the upper intestine with a higher pH and much larger surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the first pass metabolism

A

Drugs absorbed from GI tract pass into the blood stream-portal circulation
Blood travels immediately to the liver
Some drugs are intensively inactivated at the first time they pass through the liver.

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

What happens if the first-pass losses are high

A

Larger doses of the drug must be given to achieve a given plasma concentration

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

Bioavailability

A

Fraction of unchanged drug reaching the systemic circulation after administration by any route

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

Bioavailability affected by

A

ROA
Dosage form
Stability of the drug in the GI tract
Presence of food/ drugs in GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Volume of distribution

A

Vd is an apparent, theoretical volume
Reflection of the amount left in the blood stream after all the drug has been absorbed and distributed

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

What does low Vd and high Vd mean?

A

A low Vd= drug mainly confined to blood and body water— Very little has overflowed into the tissues.

A high Vd tells us that the drug is widely distributed to the tissues— A lot has overflowed into the tissues.

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

What is the importance of Volume of distribution

A

Calculation of the dose needed to achieve a critical plasma concentration

22
Q

What are the factors that affecting the drug distribution

A

Lips solubility
Membrane permeability
Blood flow
Plasma protein binding
Disease
Active transport
Drugs
Sequestration
Redistribution

23
Q

How does the binding of plasma protein affects the drug absorption?

A

High protein binding— less free drug circulating in the plasma and highest drug concentrations usually found in blood

24
Q

Only which drugs can act at receptor site?

A

Free drugs

25
Q

What is the aim of drug metabolism?

A

More water-soluble
More polar
Inactive metabolites

26
Q

In some cases some drugs become pharmacologically active after?

A

Being metabolized

27
Q

What happens in the first phase of metabolism?

A

Phase 1 = microsomal oxidation, nonmicrobial oxidation, reduction, hydrolysis, dehalogenation, provide a more chemically reactive group to increase polarity of the drug molecule and a site for phase 2

28
Q

What happens in the second phase of drug metabolism?

A

Phase 2= conjugation or synthetic reactions.

29
Q

In phase 1 of drug metabolism which molecules take place?

A

Cytochrome P450 mono-oxygenase system.— CYP3A4,CYP2D6,CYP2C.
Alcohol dehydrogenase and CYP2E1
6-mercaptpuyrine—Xantine oxidase
Noradrenalinityramine— MonoAminoOxidase

30
Q

What are the important enzymes of phase 2 of drug metabolism

A

UGT,UDP-glucuronosyltransferase
NAT, N-acetyltransferase

31
Q

What reactions occur in the phase 2 conjugation step in the drug metabolism?

A

Glucuronidation
Acetylation
Methylation
Sulfate addition

32
Q

What are the features of the metabolizing enzymes in drug metabolism?

A

Have broad substrate specifity
Multiple forms
İNTERİNDİVİDUAL DIFFERENCES in genetic expresssion
Constitutive or Inducible
May be induced or inhibited by food,alcohol,other drugs.

33
Q

What are the features of the enzyme inducing drugs

A

Enhance the liver enzymes which break down drugs
Faster rate of drug breakdown
Larger dose of affected drug is needed to get the same clinical effect
Increased amount of metabolites

34
Q

Enzyme inducing drugs

A

Phenytoin
Phenobarbitone
Carbamazepine
Rifampicin
Griseofulvin
Chronic alcohol intake
Smoking

35
Q

Features of enzyme inhibiting drugs

A

Inhibit the enzyme itself or the production of enzymes which break down drugs
Decreased rate of drug breakdown— increased plasma concentration
Reduce the dose of affected drug to produce the same clinical effect.

36
Q

Enzyme inhibitors

A

Erythromycin
Ciprofloxacin
Metronidazole
Ketoconazole
Oral contraceptives
Sodium valproate
Calcium channel blockers

37
Q

What are the steps of clearance in the kidney?

A

1- Excretion— glomerular filtration, passive diffusion, active tubular reabsorption/ secretion.

2- metabolism

38
Q

What are the steps of clearance in the liver

A

1- metabolism
2- biliary secretion— ENTEROHEPATİC CIRCULATION

39
Q

Importance of Entero-hepatic circulation

A

If a drug enters this circulation that means it has a long half-life.

40
Q

Only what type of drug is filtered

A

Unbound drug

41
Q

In which type of intrinsic clearance drug is highly affected by hepatic blood flow

A

High intrinsic clearance

42
Q

In which type of intrinsic clearance the drug clearance is depends on the metabolic capacity of the liver?

A

Low intrinsic clearance

43
Q

The actual quantity of drug removed depends on what?

A

Clearance
Concentration

44
Q

How many half-lives it should be passed in order to the drug is completely removed from the circulation?

A

4-5 half-lives.
90%

45
Q

Half life formulation?

A

T1/2 = 0.7xVd /. Cl

46
Q

What half-life does not depend on?

A

Dose
Dosage interval
Plasma concentration

47
Q

In which conditions an accumulation of drug is seen?

A

If dosing interval is shorter than excretion accumulation will be seen.
With repeated drug doses, a drug will accumulate in the body until dosing stops.

48
Q

How do you change the plasma concentrations?

A

Change the dose
Change the dosage interval

49
Q

What is the first-order process?

A

Constant fraction
Half-life
Removal rate of the drug is proportional to its concentration in the plasma

50
Q

What is zero-order process?

A

Constant amount
Rate of elimination does not change
No half-life

51
Q

Maintenance dose

A

MD= Cl x Css x T

Pharmacology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions