Flashcards in Pharm p. 242-244 Deck (42):
What variable represents Michaelis-Menten constant?
enzymatic reactions that exhibit a sigmoid curve usually ----- kinetics.
Km is ---- related to the affinity of the enzyme for its substrate.
Most enzymatic reactions follow hyperbolic
Vmax is directly proportional to the enzyme ----.
Formula for Km? Km =
Km = [S] at 1/2 Vmax
According to Michaelis-Menten kinetics, Vmax is the point at which the enzymes are ----.
In Lineweaver-Burk plot, the higher the y-intercept, the --- Vmax.
In Lineweaver-Burk plot, on the x-axis, the closer to zero, the ---- the Km and the ---- the affinity.
How can one distinguish btw reversible and non-reversible inhibitors on the Lineweaver-Burk plot?
Reversible competitive inhibitors cross each
other competitively, whereas noncompetitive
inhibitors do not.
Do irreversible Competitive inhibitors bind to the active site?
Yes, only Non-comp. don't.
T or F? Irreversible Competitive inhibitors incr Vmax.
T or F? reversible Competitive inhibitors dcr Km.
T or F? Irreversible Competitive inhibitors incr efficacy.
T or F? reversible Competitive inhibitors decr efficacy.
Which kind of inhibitors can be overcome by incr [S]?
reversible Competitive inhibitors
Formula for Vd?
Vd = (amount of drug in the body) /
(plasma drug concentration)
Liver and kidney disease decr protein binding to drugs causing --- Vd.
Drugs that are large/charged molecules and plasma protein bound have a ---- Vd.
Drugs that are small lipophilic molecules and bound
to tissue protein are found in which tissues?
All tissues, specially fat tissue
Formula for Cl?
CL= (rate of elimination of drug) /
(plasma drug concentration)
Formula for Cl in terms of Vd?
Cl = Vd × Ke (elimination constant)
If a drug is mostly found in the blood, what is its Vd?
Time to steady state depends primarily on --- and is independent of ---- ----.
dose and dosing frequency
Loading dose =
Loading dose = (Cp × Vd) / F
A drug infused at a constant rate takes --- half-lives
to reach steady state.
Maintenance dose =
MD = (Cp × CL × τ) / F
t1/2 = (0.693 × Vd) / CL
It takes --- half-lives to reach 90% of the steady-state level.
In renal or liver disease, maintenance dose --- and
loading dose is usually -----.
If a drug is mostly found in the ECF, what are the properties of the drug?
Made out of small hydrophilic molecules
after 4 half-lives, what % of the drug is remaining in body?
A constant amount of drug eliminated per unit time is called?
To treat overdose of a weak acidic drug one must administer what kind of drug?
To treat overdose amphetamines, give which drug?
Examples of 3 drugs with Zero-order elimination at
high or toxic concentrations?
Phenytoin, Ethanol, and Aspirin "PEA"
A constant fraction of drug eliminated per unit time is called?
Another name for Zero-order elimination?
Give 4 examples of acidic drug OD that Bicarbonate can treat?
Another name for First-order elimination?
In Phase II of metabolism, what is Conjugation referred to? "GAS"