hussain redha
Forum Newbie
Topics: 1
Posts: 3
|
hi all,
can u state why the use of aspirin for analgesia is contra-indicated in gout?
___________________
the azori
|
| mjl1717
Forum Hero
Topics: 960
Posts: 5,468
|
low doses decrease urate excretion
low doses can block the effects of probenicid and other uricosuric agents that decrease tubular reabsorption of uric acid.
___________________
Smell the coffee! "Is That an Osler move??"
|
| meg
Forum Guru
Topics: 62
Posts: 806
|
yes, low doses compete with urate at the proximal tubule and hence worsen gout
but at high doses aspirin is uricosuric (dont know mechanism.. anyone knows?) and hence fine in gout in high doses but unfortunately that high dose is like 4G/day and sideeffects (gastritis, bleeding, acidosis) are terrible.
|
| asmi
Forum Hero
Topics: 1043
Posts: 4,609
|
Meg, That might be related to its zero order kinetics :?:
|
| meg
Forum Guru
Topics: 62
Posts: 806
|
asmi, please could you explain how zero order kinetics would make it uricosuric? :oops:
|
| mjl1717
Forum Hero
Topics: 960
Posts: 5,468
|
I agree with asmi
I think what he is saying is the dose is very large, thus [C] is much greater then Km
v=rate of drug metabolism=Vmax[C]/[C]=Vmax
The enzyme is Saturated by a high free- drug conc. and the rate of metabolism remains constant over time and a constant amount of drug is metabolized and excreted per unit time
**Remember Km is substrate conc. where you have 1/2 Vmax
**Bottom line-at high doses drug metabolism is zeroorder-CONSTANT AND INDEPENDENT OF DOSE-WE ARE AT Vmax!!!
asmi I feel your energy :idea:
___________________
Smell the coffee! "Is That an Osler move??"
|
|
| |
| | | | | | |
Similar forum topics