module 3 Flashcards
where do drugs distribute in the body?
interstitial space
bone
muscle
plasma
adipose tissue
total body water
what form will a drug be in in the plasma?
protein-bound or free (ONLY FREE DRUG CAN DISTRIBUTE TO TISSUES)
what factors affect drug distrubtion
- blood flow to tissues
- ability of the drug to move out of the capillaries
- ability of drug to move into the cell
how does blood flow affect drug distribution?
low blood flow = limited drug distrubution
what conditions reduce blood flow?
neonates
abcesses
tumors
heart failure
shock
what are barriers to entering the target tissue
hydrophilic drugs
efflux transporters
what is the most widely studied efflux transporter?
P glycoprotein (pgp)
protects us from drugs and other toxins
active transporter
kicks drug out of the cell and will be back into the plasma or excreted
why cant plasma bound proteins pass into target tissue?
proteins are large and when theyre bound to plasma proteins theyre even larger! therefore theyre unable to pass through capillary fenestrations
what are the 2 major plasma proteins?
albumin
alpha 1 acidic glycoprotein
what type of drugs bind to albumin?
- weakly acidic drugs
- lipophillic
-responsible for most binding
what types of drugs bind to alpha 1 acid glycoprotein
-weakly basic
-hydrophillic drugs
what affects albumin concentration?
malnutrition, trauma, aging, liver and kidney disease
why is it bad if we have less albumin?
increases drug toxicity as more drugs will be FREE in the plasma
what increases alpha 1 acidic glycoprotein in the blood?
aging, trauma and hepatic function increase concentration
why does it matter if theres a higher concentration of alpha 1 acid glycoprotein in the blood?
more drugs will be protein bound and therefore therapeutic drug effects will be reduced
