5 - Aging Pharm

Question 1

how does age change drugs binding to protein?

Answer 1

inc free fraction of some highly bound acidic drugs
albumin normal in health, but may drop rapidly w/ illness > inc free conc of lots of drugs
alpha-1-acid glycoprotein inc w/ age, up further w/ illness > binds more antidepressants

Question 2

phenytoin conc in elderly

Answer 2

twice as much is free in older people, so let total level be half as much as in adults as long as they are seizure free

Question 3

which CYP450 complex is most used by drugs on market?

Answer 3

CYP3A4 (things you can’t take grapefruit juice with use this enzyme)

Question 4

first pass effect and old people

Answer 4

old people are slower at metabolizing > less first pass effect > inc effective dose more in old person than young person when you double dose

Question 5

Cockroft Gault Eqn

Answer 5

estimates renal function
CLcr = (140-age)IBW/(SCr72)
(x0.85 if female)
really shitty for old people

Question 6

MC sx from drug interactions

Answer 6

hypoTN /orthostatic changes
acute renal failure
confusion
cognitive impairment