drug distribution Flashcards
how can a drug be active
drug must leave the blood stream and enter the inter or intracellular spaces
what does drug distrubution refer to
Reversible Transfer of a Drug between the Blood and the Extra Vascular Fluids and Tissues of the body
what protiens in the plasma does drugs bind to
albumin or alpha 1 glycoprotien
why s therapeutic range useful?
shows when drug is toxic and when drug is inefective
what are the three important things when considering drug distribution
volume of distribution, clearance and half-life.
what is volume of distribution
volume of plasma that would be necessary to account for the total amount of drug in a patient’s body
the greater the Vd the …… the ability of the drug to diffuse into and through membranes
greater
how many litres should be put in if its highly protien bound
3l
how many litres should be put in if it stays in extracellular fluid but can not penetrate cells?
12
what is clearance
theoretical volume from which drug is completely removed over a period of time
what does renal clearamce depend on
concentration and urine flow rate
what does hepatic clearance depend on?
metabolism and biliary excretion
define the term half life
the time taken for the drug concentration in the blood to decline to half of the current value
what does half life depend on
Half life depends on the volume of distribution and rate of clearance.
what happens if you prolong the half life
increase of toxicity
what are the 2 parts of drug elimination
drug metabolism and drug excretion
what is the primary organ for drug excretion
kidneys
what are the three principle mechanisms for excretion
glomerular filteration
passive tubular reabsorption
active tubular secretion
what is Glomerular filtration
the process that your kidneys use to filter excess fluid and waste products out of the blood into the urine collecting tubules of the kidney
what is tubulr secretion
Tubular secretion is the transfer of materials from peritubular capillaries to the renal tubular lumen
whats the most important system for eliminating protien bound cationic and anionic drugs?
active tubular secretion
what is enter-hepatic circulation
drugs that are reabsorbed from the bile into the circulation
