Flashcards in Intro to Pharmacokinetics Deck (22)
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1
ADME
Absorption
Distribution
Metabolism
Elimination
2
Pharmacodynamics
how the drugs affect the body
3
Pharmacokinetics
how the body affects/handles the drug
4
Pharmacokinetic calculations needed for...
1. concentration dependent efficacy/toxicity
2. Narrow therapeutic index
5
Absorption
Passive
- ionized (eliminated) v. unionized (re/absorbed)
Active absorption/transport (and carrier mediated)
1. ENERGY REQUIRING
2. Saturable - competitive inhibition by other meds
3. Movement against gradients - electrochemical and concentration gradients
6
Lipid solubility in ionized v. unionized
Ionized - Lower lipid solubility = do not easily diffuse across lipid bi-layer membranes
Unionized - higher lipid solubility = easily diffuse across lipid bi-layer membranes
7
Ionization status depends on 2 factors
1. pKa of med
2. pH of membrane gradient
When pKa=pH; 50:50 ratio of ionized:unionized
8
2 body systems where pH varies and commonly impacts ionization status
GI tract
Kidneys
9
Protein binding: bound v. unbound
bound = inactive
UNBOUND = ACTIVE
10
alpha (small v. large)
unbound fraction
small alpha = less unbound
11
Phase 1 Reaction
Metabolism - alters functional groups (oxidation, reduction, hydrolysis)
12
Phase 2 Reaction
Metabolism - alters covalent linkages (glucuronidation, sulfation, acetylation)
13
Cytochrome P450 Enzyme System
Main sites: liver, GI, Brain, Kidney
14
CYP450 enzyme inducers
carbamazepine
phenytoin
phenobarbital
isoniazid
15
CYP450 enzyme inhibitors
fluoxetine
omeprazole
cimetidine
16
First pass metabolism
determines oral administration v. IV
liver metabolizes
17
Elimination via liver and kidneys:
lungs, sweat, bile/feces
18
REduced renal or hepatic function may result in ____ in dose
change
19
3 main processes of Renal Elimination
1. Passive GF
2. Passive tubular diffusion
3. Active tubular secretion
20
Passive GF
blood flow dependent
21
Passive tubular diffusion
PcT, DcT
ionization and concentraiton status dependent
22
