Pharmacodynamics and drug-receptor interaction Flashcards
pharmacodynamics
study of biochemical, cellular, and physiological effects of drugs and their mechanics of action
Chemical mechanism of drug action
chemical nature of the drug alters the physiologic environment of the target tissue to produce an effect
Antacids
increase pH of gastric lumen to neutralize gastric acid thereby decreasing irritation to the lining of the stomach
Osmotic diuretics
increase osmolarity of tubular fluid in kidney to decrease the reabsorption of water which increases urine output
chelating agents
drugs that chemically bind to target molecules
digibind
used as an antidote for digoxin toxicity
deferoxamine
used as an antidote for iron toxicity
Receptor binding
drug functions as ligands that bind to receptors that regulate cellular processes
Agonist
when it binds to the receptor, results in producing a desired response of the receptor
Antagonist
when it binds to the receptor, it stops producing a desired response of the receptor
Receptor types
ligand gated ion channels
GPCR
enzyme linked receptors
intracellular receptors
What is Kd
equilibrium dissociation constant
ratio of the dissociation rate to the association rate
Affinity
strength of interaction between a ligand and its receptor
Kd= ?
([L][R])/ [LR]
The formation of the ligand/drug-receptor complex is determined by?
affinity
Affinity constant
Ka
reciprocal of the equilibrium dissociation constant
Drugs with a high affinity have what kind of Kd?
low
Fraction occupancy of receptors= ?
[LR]/([R]+[LR])
describes the magnitude of biological effect related to the amount of active receptors— agonists can infect this