Flashcards in PK and PD General principles Deck (32):
Name an example of a Physical mechanism of action by drug.
Activated charcoal (adsorbs substance and prevents absorption)
Mannitol (osmotic activity)
Name 2 examples of Chemical mechanism of drugs.
Antacids (neutralizes gastric acids)
Chelating agents (inactivates toxic metals)
Drugs that bind R have affinity for receptor and Intrinsic activity, what does this mean?
Affinity - ability to bind R
Intrinsic activity - ability to change something on R
Drugs are classified based on Affinity and IA. What does Agonists, antagonists, inverse agonists and partial agonists have?
Agonist: + Affinity, + IA
Antagonist: +Affinity, - IA
Inverse agonist: + Affinity and Negative IA
Partial agonist: +Affinity, sub-maximal IA
Name example of Inverse agonist.
Bicuculline (binds GABA-A receptor and stimulates neurons instead of inhibiting them).
What is definition of drug action and drug effect?
Action - conformational change caused
Effect - biological function as consequence of drug
DRC that has a parallel shift means...?
DRC that has change in height of curve means...?
Change on slope of curve means...?
Changes in Potency of drug
Change in Efficacy of drug
Steep slope (small change in drug causes dramatic response), flat slope (large changes in dose to get some results)
Give an example of Synergism between drugs.
Levodopa + Carbidopa
Give 2 examples of Physiological antagonism.
1. Epinephrine + Histamine with respect to smooth muscle
2. Steroids + Insulin with respect to blood sugar
A right parallel shift in DRC means _____ was used.
A decrease in efficacy in DRC can be caused by___, ___, ___.
Rapid desensitization produced by repeated small/frequent doses of drug, rendering it ineffective.
Spare receptors are said to exist when ____>____.
EC50 > Kd
Drugs that undergo First pass metabolism will ____ their Bioavailability.
Bioavailability (F) is ___ for IV drugs and ___ for other routes.
____ binds plasma proteins, meaning 99% of drug stays in plasma.
___ (anti-malarial drug) doesn't bind plasma proteins, which means >99% will go inside tissues.
Drugs that bind plasma proteins ____ their Vd (volume of distribution).
Phase I metabolism makes drug more hydrophilic, name some reactions.
Phase II metabolism adds conjugates to drug, name some reactions
Glucoronidation (MC in body)
Name CYP inducers.
Name CYP inhibitors.
How does CYP induction/inhibition affect Pro-drugs.
CYP inducers --> increase concentration of active drug
CYP inhibitors --> decrease concentration of active drug
P-glycoproteins expel drugs from intestinal mucosa to lumen, increasing excretion. Name 2 examples of P-gp inhibitors.
Renal excretion depends on ___, ___, ___. Name factors they are affected by.
glomerular filtration (size dependent)
tubular reabsorption (ionization dependent, NON-IONIZED/lipid soluble substances are reabsorbed)
tubular secretion (Indépendant of PP binding, lipid solubility)
Alkalization of urine can be achieved by... in treatment of Barbiturate or Aspirin poisoning.
Acidification of urine can be achieved by...in treatment of Morphine or Amphetamine poisoning.
Probenecid affects concentration of Penicillin by affecting its ___.
Maintains it in blood for longer, increasing [ ].
Probenecid ___ the effectiveness of diuretics (e.g. Furosemide).
Diuretics work by binding pumps in tubular lumen, if maintained in blood, can't act on their targets.
Zero order drugs (ex. Alcohol) get excreted as ______ per unit time.
First order drugs get excreted as _____ per unit time.
constant fraction (%)
Clearance of drug predicts rate of elimination. If Cl=GFR means ____, Cl > GFR means _____, Cl < GFR means ____.
no active secretion or absorption
Drug has reabsorption
Drug has secretion
How many half lives are required to eliminate >97% of drug?