CPPS 304 exam QUESTIONS WITH VERIFIED SOLUTIONS

Receptor Macromolecule whose biological function changes when a drug binds to it What are the link between chemical actions and biological function? Receptors Emax maximum effect of a drug What happens when Emax is reached? Emax occurs when all receptors are bound What is in indication that spare receptors are present? When Emax is reached before all receptors are bound Agonist has affinity for a receptor as well as intrinsic activity at the receptor Antagonist has affinity for a receptor but no intrinsic activity at the receptor partial agonist has affinity for a receptor but lacks the full intrinsic activity of an agonist inverse agonist binds to a constitutively active receptor and inactivates it affinity the propensity of a ligand to bind to a receptor high affinity = binds readily to a receptor low affinity = spends less time bound to a given receptor intrinsic activity the action carried out by the ligand while it is bound to a receptor Kd dissociation constant (affinity of a drug for a receptor) What does the value of Kd signify? measures the propensity of a drug to release (dissociate) from a receptor What does a high Kd mean? drug readily dissociates from its receptor What does a low Kd mean? suggests high affinity for its receptor If a patient were to overdose on a reversible antagonist, what could you do? Add more agonist Irreversible or Non-Competitive Antagonists bind to receptor for life Reversible or Competitive Antagonists bind and release from a receptor and are in a constant state of flux True or False, increasing the concentration of agonist will overcome the effects of an irreversible antagonist. False What are the four types of receptors? Ion channel, G-protein coupled, Coupled to enzymes, Intracellular What type of receptor involves Acetylcholine? Ion channel What is the fastest type of receptor? Ion channel What type of receptor involves adrenergics like epinephrine? G-protein coupled What is the most common receptor type? G-protein coupled receptor What type of receptor involves receptors dimerizing after being bound by a ligand? Coupled to Enzyme Receptors Growth factors and insulin are involved in which type of receptor? Coupled to Enzyme Receptors What is the slowest type of receptor? Intracellular Steroid hormones are involved in which type of receptor? Intracellular Receptors EC50 dose that elicits 50% of the maximal response True or False? With a reversible antagonist you can still achieve the same Emax True What two types of antagonists can lower Emax? Irreversible or Allosteric antagonists What would happen to the Emax of a partial agonist compared to a full agonist? Partial agonist's Emax would be lower Quantal dose-response curve Plots the cumulative frequency of responses at a given dose What are Quantal dose-response curves good for? Predicting relative efficacy and toxicity in a population therapeutic index the ratio between the toxic and therapeutic concentrations of a drug therapeutic window Range of drug doses that can treat disease effectively while staying within the safety range. What does ADME stand for in pharmacokinetics? absorption, distribution, metabolism, excretion Bioavailability (F) amount of drug in systemic circulation/amount of drug administered What is the main site of absorption for oral drugs? small intestine What are the 4 main factors influencing oral absoprtion? molecular size, gastric emptying time, intestinal transporters, hepatic metabolism What drugs are more easily able to cross the cell membrane, lipophilic drugs or lipophobic drugs? lipophilic What drugs have more difficulty crossing membranes, polar (ionized) or non-polar molecules? polar (ionized) What happens to weakly acidic drugs in an acidic environment? They will remain un-ionized What happens to weakly basic drugs in an acidic environment? They will become ionized How can different components of food (like minerals) affect absorption? minerals can bind to drugs and reduce their absorption What are p-glycoprotein transporters? efflux pumps that push drug from enterocytes back into the lumen of the small intestine True or False? Not all drugs are substrates for Pgp transporters. True What are the four factors influencing oral absorption? molecular size, gastric emptying time, intestinal transporters, hepatic metabolism Which has the greater difficulty crossing cell membranes, polar or non-polar molecules? polar molecules