Metabolite PK Flashcards
Metabolites can affect PK of a ___ and alter pharmacologic
response to the ___
parent drug
What is the metabolite of Zidovudine?
Zidovudine triphosphate
Most effects of metabolites are ___ dependent
concentration
kf represents ___
metabolism
km represents ___
elimination
What is rate-limiting step that determine metabolite amount in the body?
kf = 0.05
km = 1.2
Formation of metabolite
What is rate-limiting step that determine metabolite amount in the body?
kf = 1.2
km = 0..05
elimination of metabolites
K ___ Km
* metabolite elimination is formation rate-limited
* t1/2 of metabolite is ___ than the t1/2 of the parent drug
* apparent t1/2 of metabolite is ___ to the t1/2 of the parent drug
* typical pattern for most drugs
- «
- shorter
- similar
K ___ Km
* Apparent metabolite elimination is metabolite elimination rate-limited
* Both the apparent and true t1/2 of metabolite is ___ than t1/2 of parent drug
* typical pattern for prodrugs
- > >
- longer
Formation-limited
- Time to reach SS is determined by ___
- Time to reach SS for metabolite is the ___ as that of parent drug
- t1/2
- same
Elimination-limited
- Time to reach SS is determined by ___
- Time to reach SS for metabolite is ___ than that of parent drug
- t1/2
- longer
Drugs that experience significant first pass effect (high EH) show ___ metabolite-to-parent drug concentration ratio after oral administration as compared to IV
high
When drugs of high EH are administered and the metabolites are inactive:
* IV administration typically leads to ___ drug response
* Low F of the drug requires ___ oral doses
- faster
- higher
When prodrugs of high EH are administered:
* A ___ onset and a more ___ response may occur after oral
administration than iv
* Low F of prodrug does not mean a ___ therapeutic effect following
oral administration
- shorter, intense
- poor
