PK/PD Flashcards
(52 cards)
1
Q
- Study of substances that interact w/ living systems
- Beneficial therapeutic effect
- Toxic effects (parasites infecting patient)
A
Pharmacology
2
Q
Deal w/ the undesirable effects of chemicals on living systems
A
Toxicology
3
Q
Study of the therapeutic uses and effects of drugs
A
Pharmacotherapeutics
4
Q
ADME
- A: absorption
- D: distribution
- M: metabolism (biotransformation)
- E: elimination of drugs
A
Pharmacokinetics (PK)
5
Q
What the body does to the drug
A
PK (pharmacokinetics)
6
Q
Study of the relationship between the concentration of a drug and the response obtained in a patient
A
Pharmacodynamics (PD)
7
Q
What the drug does to the body
A
PD (pharmacodynamics)
8
Q
- What drug has an action/effect in the body.
- Requires what 2 things?
A
- “free drug”
- Needs a therapeutic site/ or is free
9
Q
Fraction (F) of the administered dose that reaches the systemic circulation
A
Bioavailability
10
Q
Defined as 100% for intravenous administration
A
Bioavailability
11
Q
What is reduced after administration by other routes (less than 100%)?
A
Bioavailability
12
Q
By which 2 ways is bioavailability reduced?
A
- Incomplete absorption (and in the intestine, expulsion of drug by intestinal transporters)
- First-pass metabolism (and any distribution into other tissues that occurs before the drug enters the systemic circulation)
13
Q
- Absorption pattern: absorption circumvented
- Limitations/Precautions: increased risk of adverse effects
What is the route and %?
A
Intravenous 100%
14
Q
- Absorption pattern: Prompt from aq solution. Slow and sustained from repository preparations
- Limitations/Precautions: Not suitable for large volumes. Possible pain or necrosis from irritating substances
What is the route and %?
A
Subcutaneous 75 - 100%
15
Q
- Absorption pattern: Prompt from aq solution. Slow and sustained from repository preparations.
- Limitations/Precautions: Precluded during anticoagulant therapy. May interfere w/ interpretation of certain diagnostic tests (CK)
What is the route and %?
A
Intramuscular (IM) 75 - 100 %
16
Q
- Absorption pattern: Variable, depends on many factors
- Limitations/Precautions: Requires patient compliance. Bioavailability potentially erratic and incomplete.
What is the route and %?
A
Oral Ingestion 5- 100%
17
Q
Route of administration:
- Offers maximal convenience
- Absorption is often slower
- Subject to first pass effect (significant amount of agent is metabolized in gut wall, portal circulation, and liver before reaching systemic circulation)
A
Oral (swallowed)
18
Q
Route of administration:
- Direct absorption into systemic venous circulation (bypassing hepatic portal circuit and 1st pass metabolism)
A
Buccal and sublingual (not swallowed)
19
Q
Route of administration:
- Offers delivery closest to respiratory tissues (asthma)
- Usually very rapid absorption (for anesthetic gases)
A
Inhalation
20
Q
Route of administration:
- Includes application to skin or mucous membrane of the eye, ear, nose, throat, airway, or vagina for local effect
A
Topical
21
Q
Route of administration:
- Involves application to the skin for systemic effect.
- Absorption usually occurs very slowly (due to thickness of skin)
- First pass effect is avoided
A
Transdermal
22
Q
Give some examples of how factors may affect bioavailability of a drug with various routes of administration.
A
- Some of the inhaled drug accidentally gets swallowed
- Rubbing site after IM injection alters kinetics and causes vasodilation
- Oral: first pass effect
- IM injection in thigh of runner/athlete will alter absorption
23
Q
Which route of administration is increased substantially in newborns due to underdeveloped stratum corneum and increased skin hydration?
A
Skin/Topical
24
Q
***Which route of administration should NEVER be used in pediatric patients? Why?***
A
IM, bc/ drug absorption is impossible to predict
25
What changes in absorption are seen in pregnancy? Route?
**Oral:**
* N/V (pt can't absorb drug if they vomit soon after taking it) --\> should repeat dose within 1 hour if pt vomits
* Delayed gastric emptying
* Increase in gastric pH may affect the absorption of weak acids and bases
26
**Geriatric**
Most drugs are absorbed via: \_\_\_
Passive diffusion
27
**Geriatric**
Nutrients absorbed by \_\_\_.
* Vitamin B12
* Iron
* Calcium
* Magnesium
* Leucine
(may have impaired absorption in older adults)
Active transport
28
**Geriatric**
* Evidence for a decreased first-pass effect on \_\_\_\_\_.
* Results in ____ and higher plasma concentrations of drugs
* (you can give smaller doses)
* Decreased 1st pass effect on **heptic or gut wall metabolism**
* Results in **increased bioavailability**
29
* Concentration of a drug is greatly reduced before it reaches the systemic circulation
* Fraction (F) of lost drug during the process of absorption which is generally related to the \_\_\_\_\_.
* Give an example
* **First-pass effect**
* Related to **liver and gut wall**
* **Propranolol** (F) fraction of drug lose during absorption is about **25%**
30
First Pass Extraction
31
**Drug Movement: Distribution: PK**
* 2 forms of passive transport
* Paracellular transport
* Diffusion
32
**Drug Movement: Distribution: PK**
* 2 forms of active transport
* Facilitated diffusion
* Drug transporters
33
**PK: Distribution: Drug Movement**
What are the 2 ion channel examples?
* **Voltage activated Na channel** (depolarization/hyperpolarization)
* **Ligand gated Na channel** (ACh)
34
* relates the amount of drug in the body to the serum concentration
* determined by the physiologic volume of blood and tissues and how the drug binds in blood and tissues
* used to calculate the loading dose of a drug that will immediately achieve a desired steady-state concentration
* *gentamicin*
PK: Volume of Distribution
35
Pediatric patients are made up of more \_\_\_\_. So what type of drugs do we give them?
Water, give them water loving drugs bc/ they distribute well.
36
What drugs increase plasma levels? Be careful with dosing this medication if the patient is fluid overloaded.
Diuretics
37
* Largest protein in the body
* Lots of drugs bind to it
* ASA is 98 - 99% bound to this protein
* At higher doses it becomes "extended release drug"
Albumin
38
\_\_\_\_ are not available to exert pharmacologic effects.
Protein-bound molecules
39
* Anticoagulant w/ narrow margin of safety/narrow therapeutic window *(very small difference in doses can move from therapeutic to toxic range)*
* 98% protein bound
* Addition of another highly protein bound drug such as ASA, competes for the protein which results in more free drug for both ___ and ASA through inhibition of clearance of \_\_\_\_.
Warfarin
40
Pediatric patients ARE NOT LITTLE ADULTS
* What are 4 difference in distribution in peds patients compared to adults?
* Give examples
* **Increased total body water** (as % of total body weight)
* **Increased extracellular fluid volume** (is markedly different compared to adults)
* *Ex: Gentamicin distribution volumes is 0.48 L/kg in neonates / 0.20 L/kg in adults*
* **Decreased binding of drugs to plasma proteins is decreased in newborn infants**
* **Decreased amount of body fat is substantially lower in neonates than in adults**
41
What are 2 differences in distribution in pregnancy?
* **Increased body fat** (volume of distribution of fat soluble drugs may increase)
* **Decreased plasma albumin concentration** (increases volume of distribution of drugs that are highly protein bound)
42
* Decreased total body water
* Decreased lean body mass
* Increased body fat
* No change or Decreased serum albumin
* Increased alpha acid glycoprotein
* Decreased CO (cardiac output)
PK: Distribution for Geriatric patients
43
•specific molecules in a biologic system with which drugs interact to produce changes in the function of the system.
Receptors
44
Which drugs bind to and activate the receptor in some fashion, which directly or indirectly brings about the effect?
Agonist drugs
45
•binds to its receptor but produces a smaller effect at full dosage than a full agonist
Partial agonist
46
Which drugs, by binding to a receptor, compete with and prevent binding by other molecules?
Antagonist drugs
47
Which drugs bind to the same receptor molecule but do not prevent binding of the agonist?
* may enhance or inhibit the action of the agonist molecule
* not overcome by increasing the dose of agonist
Allosteric drugs
48
•an antagonist that cannot be overcome by increasing the agonist
Irreversible antagonist
49
Where does the drug action happen?
At the receptors
50
Allosteric binding
A + C (enhances activity of A)
Ex: synergism (1+1=3)
51
Drug has BTDT "been there and done that"
Now what happens?
Metabolism and excretion
52
* What is the most important organ for drug metabolism?
* Which other organ plays an important role in metabolism of some drugs?
* Which drugs are metabolized in many tissues (liver, blood, intestinal wall)? and why?
* Liver (most important)
* Kidney (some drugs)
* Esters, bc/ wide distribution of their enzymes
