IV Bolus - 1 Flashcards
Definition
Pharmacokinetics (PK)
the study of the process by which a drug is absorbed, distributed, metabolized, and excreted by the body
what the body does to the drug - ADME
definition
Optimal drug therapy
determination of optimal dosage regimen (how many mg and how many times a day)
definition
IV Bolus
a rapid injection that ensures the entire dose enters the systemic circulation immediately
IV bolus input:
What does the plasma [ ] vs time graph look like?
One compartment model assumptions
- The body acts like a ___ homogenous compartment and drug rapidly distributes uniformly in it.
- The drug is in rapid ___ between the blood and the tissues.
- Changes in the plasma concentration of drug will result in ___ changes in tissue drug levels.
- single
- equilibrium
- proportional
One compartment model
Elimination follows a ___ order process: the ___ rate is proportional to the [ ] of the drug
- first
- elimination
First order elimination
zero order is eliminating the same amount every time whereas first order eliminates the same precentage of the amount remaing each time.
Example: decreasing by 10 each time vs decreasing by 10% each time
Unit for kel
/h
Unit for Vd
L
Vd is the size of the compartment
IV Bolus equation
Vd equation
Different drugs show different ___ after a given dose, and thus different ___
- Cp0
- Vd
T or F: Cp0 is the y intercept on a [ ] vs time graph
true
Vd depends on the ___ properties of the drug.
physicochemical
Hydrophilic compounds
* Do not cross ___ readily
* ___ Cp0 given a dose
- membranes
- higher
Lipophilic compounds
* have ___ tissue distribution
* ___ Cp0 given a dose
- better
- lower
Vd is a measure of drug ___ in the body
distribution
Volume of distribution (Vd)
- In most cases, Vd dose not correspond to a ___ volume.
- Special occasions: if drug is confined to the bloodstream (volume ~ ___ ) or total body water (volume ~ ___ ), then the pharmacokinetic parameter Vd may reflect the physiologic volume.
- physiologic
- 5 L
- 42 L
definition
half life
The time it takes for half of the drug in the body to be eliminated or the time it takes for the plasma concentration to decrease by a half
definition
Clearance (CL)
proportionality constant relating the rate of drug elimination and the plasma concentration
Unit for CL
L/h
CL equation
- If drug A has a higher kel than drug B, it is eliminated ___
- if drug A has a higher CL than drug B, it is eliminated ___
- faster
- faster
definition
Elimination rate constant (kel)
fractional rate of loss of drug from the body
kel vs. CL
* kel = ___ rate of drug loss from the body.
* CL = ___ of drug-containing plasma from which drug is completely cleared.
- fractional (10%)
- volume (L/h)
Theoretically, CL cannot exceed ___ (because drugs reach the drug-eliminating organs via the blood pumped by heart)
cardiac output
equation for kel and t1/2
For a drug that has linear kinetics, if we double the dose then the plasma
concentration will ___ at each time point.
double
For a drug that has linear kinetics, if we double the dose then the plasma
concentration will ___ at each time point.
double
linear kinetics
Pharmacokinetic parameters ___ , ___ , and ___ are constant, that is, they are independent of dose
kel, CL, Vd
Non linear kinetics
occurs when one or more ADME processes shows ___
* dose ___ PK
saturation
* dependent
Non linear kinetics
___ and ___ are dependent on dose
CL, Vd
Linear kinetics
When the dose is higher, Vd will
A) increase
B) not change
C) decrease
not change
Linear kinetics
T or F: In linear kinetics, AUC is proportional to dose.
true
Linear kinetics
As time passes after drug administration, CL, K el or Vd will
A) increase
B) not change
C) decrease
not change
