Pharmacodynamics & Pharmacokinetics Flashcards
All of the following are diuretics. Which of the following
Diuretics results in hyperkalemia?
- Acetazolamide
- Furosemide
- Hydrochlorothiazide
- Spironolactone
- Mannitol
- Spironolactone
What is the SMALLEST body fluid compartment?
A. ICF (Intracellular fluid – inside cells)
B. ECF (Extracellular fluid – outside cells)
C. Blood Plasma
D. Interstitium – (between cells -
excluding vascular compartment)
C. Blood Plasma
What ion channel does lidocain work on?
Na+
What ion channel does sulfonylurea act on?
K+
What ion channels do Nifedipines act on?
Ca2+
What ion channels do **zepam drugs act on?
Open Cl-
What amino acid is Nitric Oxide derived from?
-Arginine
What amino acid is Epinephrine derived from?
-Tyrosine
What amino acid is Serotonin derived from?
Tryptophan
What enzyme does Acetazolamide inhibit?
Carbonic Anhydrase
What enzyme does Statins inhibit?
HMG-CoA reductase
What enzyme does Ciprofloxin inhibit?
Bacterial gyrase
What enzyme does allopurinol inhibit?
Xanthine oxidase (treats gout)
What enzyme does Methotraxate inhibit?
Dihydrofolate reductase (cancer treatment)
What does Sildenafil inhibit?
PDE5 (Treats Erectile Dysfunction)
Where is PDE5 located?
- Corpus cavernosum
- Heart
- Blood vessels
- Eyes (PDE6)
Many molecules act as second messenger in cytoplasm of our cells.
One of these is NOT a common second messenger.
A. Cyclic AMP (cAMP) B. Inositol bisphosphate (IP2) C. Inositol triphosphate (IP3) D. Calcium E. Diacyl Glycerol (DAG)
B. Inositol bisphosphate (IP2)
The following are four drugs whose mechanism of action
is by activating different classes of receptors.
Choose the correct order of drugs starting
from fastest onset of action to the slowest onset.
Cortisol Insulin Norepinephrine Nicotine
Norepinephrine Nicotine Cortisol Insulin
Nicotine Norepinephrine Insulin Cortisol
Nicotine Insulin Norepinephrine Cortisol
Nicotine -> Norepinephrine -> Insulin -> Cortisol
What is a partial agonist?
-a drug that produces the effect, but cannot produce the same maximal effect
Do antagonists have any effect alone?
No
What makes a drug an inverse agonist?
-it has the opposite effect of an agonist
Which of the following drugs is an example of an inverse agonist:
A. Propranolol B. Epinephrine C. Histamine D. Diphenhydramine (Benadryl) E. Norepinephrine (Levofed)
D. Diphenhydramine (Benadryl)
What is the difference between potency and efficacy?
- potency compares ONLY the EC50 concentrations needed to achieve and effect
- efficacy compares ONLY the maximal efficacy of the drugs
What is the ratio for therapeutic index?
Lethal dose 50 / Efficacious dose 50
What common drugs (and their conditions they treat) have low therapeutic indices?
Theophylin (asthma)
Quinine (anti-arrhythmic)
Lithium (Bipolar)
Digoxin (cardiac)
What’s the safest pregnancy risk category?
A
What’s the scariest pregnancy risk category?
X
Why does a partial agonist produce below maximal biological effects compared to a full agonist?
Full agonist will only bind “active” receptor, thus pulling more receptors from inactive to active (equilibrium).
Partial agonists bind both active and inactive receptors, so there is no pull.
**Note: inverse agonist will bind the inactive form of the receptor alone
Can an antagonist also negate the effect of an inverse agonist?
Yes
When is a reaction zero order?
- when the concentration of substrate is much greater than Km
- rate is constant and independent of substrate concentration
When is a reaction first order?
- when there is a low concentration of drug compared to enzymes
- small increase in drug concentration will result in proportional increases in reaction velocity
Which form is active as blood thinner?
A. Albumin-bound Warfarin
B. Free Warfarin
C. Both
B. Free Warfarin
When drug conc. is measured, what form(s) are measured?
A. Albumin-bound Warfarin
B. Free form of Warfarin
C. Both bound and free forms
C. Both bound and free forms
What is Ke?
-elimination constant
(T/F) the Half life for the elimination of a drug via zero order kinetics is constant.
F. Half life for zero order kinetics is dose-dependent/non-linear
The concentration of digoxin (Digitalis) in patient with
Congestive heart failure was 100 nanograms / deciLiter.
After two hours, the concentration was 90 nanograms / dLiter.
If digoxin is being eliminated by first order kinetics, what
will be concentration after two more hours?
A. 80 ng / dL
B. 81 ng / dL
C. 50 ng / dL
D. 75 ng / dL
B. 81 ng / dL
What is drug clearance defined as?
- the fixed volume of fluid cleared of the drug per unit time
- units = volume/time
What is the importance of the equation: log Ct = - K t/2.303 + log Co
-If you know the concentration of drug at time zero,
you can calculate drug concentration at any time before or after
What is this equation for? T1/2 = 0.7/Ke
you can use it to calculate half life of a drug if you know the elimination constant
How does alcohol consumption affect gluconeogenesis?
-inhibits it
**can lead to hypoglycemic coma in alcoholics low on glycogen
What does it mean for a drug’s administration to be steady state?
-the amount of drug in = the amount of drug out
Does a faster rate of drug infusion change the time needed to achieve steady state?
-no, only the steady-state concentration changes
What does the time needed to reach a steady state depend on?
ONLY the half-life of the drug
-dosage has no effect
How many half lives are considered to be the time needed to reach steady state?
4-5
What is the Loading (Bolus) Dose?
the amount of drug needed to immediately achieve a steady state concentration of drug????
You are giving one of these drugs to a patient with
a GFR of 60 ml / min (normal GFR is 120 ml / min).
What schedule is appropriate?
- Keep loading dose same, and reduce maintenance dose
- Reduce both loading dose, and maintenance dose
- Keep loading dose and maintenance dose same
- Reduce loading dose, and keep maintenance dose same
- Keep loading dose same, and reduce maintenance dose
Which one the following drugs has a high / large
therapeutic range / index?
A. Penicillin B. Theophylline C. Quinine D. Lithium E. Digitalis F. Warfarin
A. Penicillin
50 year-old male patient; you prescribe a drug with a Half life 2 hours. Volume of distribution = 100 liters
Desired Steady-state concentration 10 milligrams / liter.
How long does it take to reach steady-state?
A. 2-3 hours B. 4-6 hours C. 8-10 hours D. 8-10 minutes E. 80-100 hours
-C. 8-10 hours
50 year-old male patient; you prescribe a drug with a Half life 2 hours. Volume of distribution = 100 liters
Desired Steady-state concentration 10 milligrams / liter.
- Calculate the bolus (loading) dose
A. 100 milligrams
B. 1 gram
C. 10 grams
D. 10 milligrams
-B. 1 gram
The plasma digoxin level is 4 ng/mL. Renal function is normal, and the half-life for digoxin in this patient is 24 hours and the drug is being eliminated by first order kinetics. How long should you withhold digoxin in order to reach a safer, yet probably therapeutic, level of 1 ng/mL?
A. 1 day B. 2 days C. 3 days D. 4 days E. 5 days
-B. 2 days
A narcotics addict is brought to the emergency room in a
deep coma. His friends state that he took a large dose of
morphine 6 hours earlier. An immediate blood analysis shows a morphine blood level of 0.5 mg/L. Assume that morphine has first order kinetics with the following parameters in this patient:
Vd = 200 L, half-life = 3 hours.
How much morphine did the patient receive 6 hours earlier?
A. 50 mg B. 100 mg C. 200 mg D. 400 mg E. 800 mg
-D. 400 mg
