[1] Pharmacokinetics I (CH2) Flashcards
1
Q
there are 2 types of drug administration, what are they?
A
enteral and parenteral
2
Q
what are the 3 types of enteral drug administration to remember?
A
oral
sublingual/buccal
rectal suppository
3
Q
what are the 4 types of parenteral drug administration to remember?
A
inhalation
injections (IV, IA, SC, IM, intrathecal)
topical
transdermal (patch, iontophoresis, phonophoresis)
4
Q
A
most drugs, lipid soluble
5
Q
A
easy and convenient to self-administer
6
Q
A
- *** first pass effect (decreases amount of drug reaching blood and eventual target)
- some drugs (peptides, small proteins, etc.) are broken down by the gut, which could lead to potential irritation of the GI tract
- factors such as food, vomiting, and diarrhea may interfere
7
Q
what is the first-pass effect?
A
The first pass effect is a phenomenon where GI –> portal vein –> metabolism by liver results in a reduced concentration of the active drug in systemic circulation and eventual target site
8
Q
A
nitroglycerin
9
Q
A
- rapid onset of action
- absorbed through oral mucosa and hits bloodstream
- avoids first pass metabolism by liver
10
Q
A
excessive dry mouth can influence absorption
11
Q
A
laxative suppository
12
Q
A
- avoids first pass metabolism by the liver
- may be given to pt who is unconscious or vomiting
- useful to treat local rectal condition (ie. hemorrhoids)
- useful to stimulate GI movement in cases of constipation
13
Q
A
- some drugs may irritate the rectal mucosa
- may be poorly or incompletely absorbed
- pt may have trouble self-administering suppository
14
Q
things to note about parenteral routes of drug administration
A
- generally parenteral admin allows the drug to react the site of action through a more direct or “targeted” route, making the quantity of the drug when it reaches the site more predictable
- parenteral admin is not administered through the GI tract and is usually not subject to the first-pass metabolism of the liver
15
Q
A
general anesthetic / asthma
16
Q
A
- may be used for drugs in gaseous or volatile state
- may be used for drugs suspended as tiny droplets
- rapid onset; large SA and high blood flow (ie. lungs)
- useful to directly treat respiratory disorders
17
Q
A
- some drugs can irritate the alveoli or respiratory tract
- patient may have trouble self-admin
- patient compliance
18
Q
- list all the types with their respective abbreviation
A
IV; Intravenous IA; Intra-arterial SC; Subcutaneous IM; Intramuscular Intrathecal
19
Q
- examples of each injection type along with a quick tidbit about them
A
IV: ex. analgesics … quick delivery of known amount
IA: ex. anti-cancer meds … very targeted delivery to tumor
SC: ex. insulin, anticoagulants … relatively easy route for drugs that can’t do oral
IM: ex. vaccines, botox … skeletal mm. is a large target
Intrathecal: specific site such as spinal subarachnoid space, tendon sheath,
bursa—may connect to catheter and pump
20
Q
A
antimicrobials, anti-inflammatory steroids
21
Q
A
- easy use for patient (applying cream or ointment to skin)
- small amounts typically do not penetrate deep enough for adverse systemic effects
- could apply topically for a systemic effect where you may get absorption into your blood (nasal spray, eye drops, topical NSAID)
22
Q
A
- if large amounts are applied often enough to a large body SA, drug may be absorbed into the blood and cause adverse effects systemically
23
Q
A
analgesics (acetaminophen), nicotine
24
Q
A
- easy application for the patient by applying patch to skin
- we want the drug to pass through the skin and into the bloodstream for systemic effect
- the use of TD patches is expanding for issues like: angina, high BP, contraception
25
[parenteral drug admin.]: TRANSDERMAL PATCH disadvantages
- the drug has to pass through the skin in order to work
| - patients need to be reminded to take off the old patch and dispose properly
26
[parenteral drug admin.]:
- what is transdermal iontophoresis
- what is transdermal phonophoresis
iontophoresis uses an electrical current to drive drug through skin to subcutaneous tissue
phonophoresis uses ultrasound waves to enhance the movement of the drug through the skin
27
define bioavailability
“percentage of the drug administered that reaches the bloodstream”
28
If give 100 mg of drug X (IV injection) and measure 100 mg of drug X in bloodstream, what is the bioavailability?
bioavailability is 100%
29
If give 100mg of drug X (orally) and measure 50mg of drug X in bloodstream, what is the bioavailability?
bioavailability is 50%
30
what can affect bioavailability?
- route of admin
- clearance or metabolism of drug (ie. first pass effect)
- drug ability to pass through various membranes
31
what letter represents bioavailability
F
32
for a drug given via IV, bioavailability (F) is usually ...
100%
33
what 4 factors are considered with the distribution of drugs within the body
– Tissue permeability
– Blood flow
– Binding to plasma proteins
– Storage in body compartments
34
[drug distribution within the body]: Tissue Permeability
| - a highly lipid-soluble drug may __, whereas a large nonlipid-soluble drug may __
Highly lipid-soluble drug may potentially reach all body compartments and enter cells, where as large nonlipid-soluble drug may remain primarily in the compartment where it is administered (e.g. GI)
35
[T/F]: a drug circulating in blood will gain greater access to tissue that is more highly perfused by blood
True
36
where would we find it difficult to get a drug from the blood stream to an area on the body that doesn't get as much blood flow?
sinuses
37
if a pt possesses a disease that reduces blood flow, what is to be expected?
some tissues may reduce drug delivery
38
[T/F]: some drugs from reversible bonds to albumin or other plasma proteins
True
| some drugs may be 90% protein bound and 10% free in plasma
39
[T/F]: unbound or "free" drug(s) is able to reach target tissue and exert its pharmacological effect
True
40
what is "volume of distribution (Vd)" ?
Vd is just an arbitrary figure (not real volume) that reflects drug distribution relative to the TBW in a human. It is calculated as the ratio of amount of drug administered to the drug [ ] in plasma. This can be written as:
Vd = (amount) / ( [ ] plasma )
41
what is the normal TBW for a male
42 L of TBW
42
Vd for drug X < 42L
| - what does this indicate?
indicates that drug X may be bound to plasma protein and retained in the bloodstream
43
Vd for drug X > 42L
| - what does this indicate?
indicates that drug X may be concentrated in some tissue, such as adipose/fat
44
following drug admin & abs, drugs are often stored in the body in these major sites:
adipose/fat
bone
muscle
organs (liver, kidneys)
45
what serves as a primary site for lipid-soluble drugs?
adipose/fat
46
due to the slow nature of fat metabolism and poor blood supply, drugs tend to ___ in adipose/fat
due to the slow nature of fat metabolism and poor blood supply, drugs tend to [remain for long periods of time] in adipose/fat
47
in what body site can some toxic heavy metals such as lead be stored in?
bone
48
what body site may serve as a long term storage of compounds?
muscle
49
drugs transported into [this body site] may form reversible bonds with intracellular structures
drugs transported into [muscle] may form reversible bonds with intracellular structures
50
[T/F]: just like muscle, organs such as the liver and kidneys can serve as a site for drugs to get into cells and form intracellular bonds
True
51
what are some of the adverse consequences of drug storage?
- tissue damage may occur when exposed to high [ ] of drugs, drug metabolites, or other toxic materials... this becomes problematic when storage sites such as adipose/fat "soak up" the drug, which could lead to a "leakage" of the drug from the site
- this ultimately prolongs the drug effect as well as extends any adverse rxns
52
provide the abbreviations for the following:
- timed release
- sustained release
- extended release
- prolonged release
- controlled release
TR, SR, ER, PR, CR
53
what perks does CR drug delivery offer
- slower/more prolonged absorption of drug
- decreases the # of dosages needed throughout the day
- prevents large fluctuations in plasma and maintains delivery while sleeping
54
when targeting drug delivery, what 2 things are we thinking about
- nanoparticles... facilitate movement across membranes
| - antibodies... attached to drugs that target the "antigen" on cells
