Tuesday, October 26, 2010

If the dose of a medicine is changed to x times the original value then how will the half-life change?

To be more specific if a patient takes 0.5mg of clonezepam what is the half-life.And when he takes 0.25mg of clonezepam what is the halflife.
Also when he takes 1mg,2mg,etc what is the half life.
It would also help if i can get a formula that can give me the relation between old halflife & new halflife when the dose is changed.If the dose of a medicine is changed to x times the original value then how will the half-life change?
I am not a pharmacist and can not say positively for that medication.
Some medications the half life is a fixed constant. if 1 gram becomes 0.5 left in the blood stream in 1 hr, then 10 grams becomes 5 grams in 1 hr.
Some medications don't have a "half life" they have a fixed metabolization rate. your liver can process appx 0.75 oz of alcohol per hour. it does not matter if BAC is 0.001 or 0.35. (except that the 0.001 will be completely gone before 1 hr is finished)
some medications will have a sort of "combined" version... some being metabolized at the fixed rate and some half-life effect.
I didn't think the half life changed when you changed the dose if there are first degree kinetics (most drugs). In this case the reports I have seen on the internet say that the half life is about 35 hours (depending on the patient).

No comments:

Post a Comment