Video 7&8 PB Pharmacokinetics&Pharmacodynamics Flashcards
What is the Km (Michaelis Kinetics) formula?
Km = (S) at 1/2 V max
What is inversely related to the affinity of the enzyme for the enzyme for its substrate?
Km
What is directly proportional to the enzyme concentration?
V max.
How can you explain the Lineweaver -Burk plot?
The further to the right the X-intercept (i.e., closer to zero), the greater the Km and the lower the affinity.
In the Lineweaver-Burk plot what is the formula for Slop?
Slop = Km/Vmax
Which are the characteristics of Competitive inhibitors (Reversible)?
Resemble Substrate: Yes. Overcome by increased Substrate concentration: Yes. Bind active site: Yes. Effect on Vmax: Unchanged. Effect on Km: increase. Pharmacodynamics: decreased potency.
Which are the characteristics of competitive inhibitors (irreversible)?
Resemble Substrate: Yes. Overcome by increased Substrate concentration: No. Bind active site: Yes. Effect on Vmax: Decrease. Effect on Km: Unchanged Pharmacodynamics: decreased efficacy.
Which are the characteristics of Noncompetitive inhibitors?
Resemble Substrate: No. Overcome by increased Substrate concentration: No. Bind active site: No. Effect on Vmax: Decrease. Effect on Km: Unchanged. Pharmacodynamics: decreased efficacy.
Which are the 4 pharmacokinetics equations?
1) Volume of Distribution.
2) Clearance.
3) Loading Dose.
4) Maintenance Dose.
How is Volume of distribution calculated?
Vd = amount of drug in the body / Plasma drug concentration
At which compartment works the drug if the Volume of distribution are low, medium or high?
Low: Blood.
Medium: ECF.
High: All tissues including fat.
How is Clearance calculated?
CL = Rate of elimination / Plasma drug concentration.
Css (Steady state concentration) X Volume of distribution, this formula belong to…
Loading dose.
How is Maintenance dose calculated?
Css X Clearance.
What does Bioavailability mean?
Fraction of administered drug reaching systemic circulation unchanged. IV dose, F=100%.
What does the function of the Half-life in drugs?
It is the time required to change the amount of drug in the body by 1/2 during elimination (or constant infusion).
Property of First-order elimination. It will be 94% after 4 half-life.
What term describes the maximum effect a drug can produce?
Efficacy.
What term describes the measure of the amount of drug needed to produce a given result?
Potency.
What term describes the dose of a drug that produces the desired effect?
Effective dose (ED)
What term describes the dose of a drug that produce death?
Lethal dose (LD).
What term describes the measure of the safety of a drug?
Therapeutic index.
How is therapeutic index calculated?
LD50/ED50
How does a competitive antagonist affect the dose-response curve?
Shifts it to the right (increased ED50)
How does a Noncompetitive antagonist affect the dose-response curve?
Shifts it downward (decreased maximal response)
