Pharm Module 1 Flashcards
how to calculate bioavailability
area under curve for IV drugs
IV route has what bioavailablity
- 100%
when is the bioavailability of drugs measured
- after the first pass effect
acidic drugs bind what
- albumin
basic drugs bind what
- alpha1 acidic glycoprotein
hydrophobic drugs bind what
- lipoproteins
steroid hormones bind what
- globulins
what part of the drug can be cleared renally?
- the free, unbound fraction of the drug
if you have a high volume of distribution, where does the drug go?
- little in the plasma
- more in the interstitial and intracellular fluid
if you have a low volume of distribution, where does the drug go?
- more in the plasma
how to calculate volume of distribution
Vd = Q/Cp
Q= amount of drug in body Cp= plasma drug concentration
Clearance and plasma concentration of a drug with high Vd
- low clearance
- low plasma concentration
clearance and plasma concentration of a drug with low Vd
- high clearance
- high plasma concentration
how to calculate renal clearance
CL = UV/P
U= drug concentration in urine V = flow rate P = plasma concentration of drug
half life of drug formula considering CL
t1/2 = (0.7*Vd)/CL
half life of a drug as Vd increases
- will also increase
half life of a drug as CL increases
- will decrease
calculation of elimination rate constant (Ke)
Ke = CL/Vd
half life concentration in regard to Ke
t1/2=0.7/Ke
what does a higher elimination constant mean
- faster the drug is eliminated from the body
how to calculate maintenance dose
MD = (CpCLт)/F
т=dosage interval
F=bioavailability
Cp=plasma concentration at steady state
how to calculate loading dose
LD = (Cp*Vd)/F
F = bioavailability
Cp=plasma concentration at steady state
what is loading dose
- single dose that will distribute across the body to produce a single therapeutic concentration
