Pharmacology: Pharmacokinetics and dynamics Flashcards
What is the volume of distribution?
Theoretical volume of drug in body in relation to plasma volume
How many half lives does it take to reach steady state?
4-5
How do you change the dose in renal impairment?
usually have lower maintenance dose, but loading dose unchanged
What does tachyphylactic mean?
A decrease in the response to a drug after repeated use. Ie. nitrates, niacin, LSD, MDMA
What is a competitive antagonist?
shift the curve to the right so you get decreased potency. You can overcome with more agonist substrate- diazepam as agonist and flumazenil as competitive antagonist
Non competitive antagonist?
Can’t overcome with more substrate as it is shifts curve down (decreased efficacy). You can’t overcome with more substrate.
What is a partial agonist?
works at the same site as a full agonist by less effect (decreased efficacy)
Zero order elimination vs first order elimination?
zero order is the same regardless of the concentration, first order means the the rate changes with fraction of drug (faster rate for more concentration of the drug, as the drug decreases, the rate decreases). Most drugs are first order elimination.
What is Phase 1 and Phase 2 elimination?
Phase 1 (geriatric patients lose first), reduction, oxidation, hydrolysis, slightly polar, water soluble metabolites. Phase 2 is conjugation (methylation, gluuronidation, acetylation, sulfation) polar inactive metabolites.
Efficacy vs potency?
Efficacy is the maximum effect a drug can produce, potency is the amount of drug needed to produce effect? unrelated!
What does histamine 1 receptor do?
pain, pruritis, increased nasal secretions, bronchoconstriction, , increased vascular permeability
what does cholinesterase do?
breaks down acetylcholine into choline and acetic acid
What does D1 receptor promote?
vasodilation. Example Fenoldopam for D1 will treat postoperative hypertension
What does midodrine do?
is an alpha 1 agonist so promotes increased vascular tone and used to treated orthostatic hypotension
What is histamine (scombroid poisoning)?
Dark fish, tuna, mahi-mahi, mimics anaphylaxis
