Drug Receptors (Pharmcodynamics) Flashcards
How does a drug create a physiological response? What is an acceptor and how does it affect drugs?
It alters the rate or magnitude of an already existing cellular response (doesn’t create new response)
-acceptors are entitites that do not directly cause any change in responses (example serum albumin) but do alter pharmcokinetics of the drug action
What is an agonist? Primary agonist? allosteric agonist? partial agonist? inverse agonist? Draw on a response/dose log graph
- agonist: drug that binds to phsyiological receptors and mimic the effect of the existing compound
- primary agonist: drug binds ot the same recognition site as the endogenous agonist
- Allosteric agonist: bind to a different region on the receptor (not the like a primary)
- partial: only partly as effective regardless of dose given
- inverse: gives a opposite response to an agonist (so if agonist increase BP, inverse decreases BP)
What is the difference between an antagonist and a inverse agonist? Give an example w/ BP
- inverse agonist will do the opposite of an agonist
- antagonist w/o an agonist will give no response
- example: increasing BP w/ an agonist. adding an inverse agonist will decrease BP (regardless if agonist is present or not). giving an antagonist will only decrease BP if agonist present (by itself, antagonist gives NO response!!!)
Draw the dose log/response curve for the following: competitive antagonism, non competitive antagonism, antagonism, and potentiation
pg 62 of week1 course notes
T/F. digoxin is specific to Na/K ATPase of the heart
False. ubiquitous (non specific)
What is tachyphylaxis
Chronic administration of nitrovasodilators to treat angina results in rapid development of complete tolerance
_____ determines the quantitative relationship between dose and response, and do so by _____. The _____ may limit the maximal effect a drug may produce
- receptors
- selectivity
- total number of receptors
Name the three types of antagonism, number of receptors, and describe w/ examples.
- pharmacological antagonism (1 receptor): both agonist and antagonist compete for same receptor
- physiological antagonism (2 receptors): two agonist bind to two different receptors. each agonist elicits its own physiological response but is opposite!!!
- Example: giving a medication for drowsyness (benodril) and then drinking a cup of coffee (caffeine) - chemical antagonism: (0 receptors): antagonist directly interacts w/ agonist.
- protamine: positively charged so it neurtralizes negatively charged heparin
What is the key difference between competitive and non-competitive antagonists?
-competitive antagonists can be overcome but a lot of agonist, while non-competitive (or irrevisible) antagonists will always keep the agonist from reaching max potential (unless present in super low doses where very high doses of agonist can cause max response)
What is the function of phenoxybenzamine? What time of agonist or antagonist is it? What happens when you give too much? How about protamine, agonist or antagonist and what type?
- phenoxybenzamine is an irreversible adrenoceptor antagonist that is used to control hypertension caused by catecholamines released from pheochromocytoma, a tumor of the adrenal medulla. It lowers BP. Too much, and you will lower BP too much so you give a pressor agent (physiological antagonist) that works on different receptor
- protamin chemical inactivates heparin, it is a chemical antagonist
What is the function of benzodiazepine? What type of drug is it, agonist, antagonist, or something else? Net effect
-benzodiazepine is an allosteric modulator that binds noncompetitively to ions channels activated by GABA, enhancing the net activating effect of GABA on channel conductance
A partial agonist concentration-effect curve most closely resembles what? How are partial agonists used clinically?
full agonists in the presence of a irreverisble antagonist (not sure about this one)
-used clinically as antagonists because it competes w/ full agonists for receptors and thus can inhibits full agonists
What is buprenorphine?
It is a partial agonist of opoid receptors that is safer than morphine because it produces less respiratory depression in overdose. Can cause withdrawal in morphine addicted patients.
Draw a graph illustrating relative potency and relative efficiacy
look in course notes
What are the three variables associated w/ drug-receptor interactions? What assumptions must be made when quantifying dose response? (5)
- dose, time, effect
assumptions: intensity prop to number of receptors bound, one drug binds one receptor, amount of drug bound to receptor is very small compared to total drug available, binding is reversible and short duration, binding of one receptor doesn’t affect another
