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The following message was posted to: PharmPK
There seems to be different philosophies out there regarding dosing of
antibiotics in patients receiving hemodialysis. Some believe that
manufacturer recommended extra doses to be administered after dialysis
can be avoided by administering the entire dose post dialysis. Examples
would include drugs like Pip/Tazo, Aztreonam, Ceftazidime, Fluconazole
etc.
Others believe that a supplemental dose is a must regardless of the
actual timing of the dose. This group of clinicians argues that a
supplemental dose is necessary to bring the patient back to "steady
state" even if it is given together with the regular dose after the
dialysis session.
Those of you, who actually do dialysis dosing pharmacokinetic studies-
which philosophy do you support?
Thanks,
Alla Paskovaty, PharmD
Clinical Coordinator in Infectious Diseases
1275 York Ave, Schwartz 526
NY, NY 10021
Tel: 212-639-7212
Email: paskovaa.aaa.mskcc.com
[A timely question for me. I was looking to develop a teaching module
for hemodialysis and have had a brief look at the literature. I have
some questions.
* Are there any simple PK models for hemodialysis?
*I gather there are low flux and high flux systems with different
M.Wt cut-off characteristics. Has anyone developed an equation for
Dialysis clearance vs M.Wt for each of these systems?
- db]
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Alla
Interesting question. We have done some studies looking at the PK of
aminoglycosides in patients with ESRD and receiving HD. Some
specific findings include: 1) the intradialytic clearance of Ags
approaches that of patients with normal renal function (but does not
exceed) and 2) that the total CL of Ags in the interdialytic period
is approximately equal to that provided by a 4 hour dialysis
session. So dialysis helps to temporarily "normalise" the PK profile.
As far as dosing in relation to HD goes - it depends on the schedule
dependence of your drug. If you are interested in time above MIC
then dosing after HD would seem appropriate. If you are interested
in a high Cmax:MIC ratio within a defined total exposure level then
dosing immediately before HD would seem appropriate.
Neither of these schedules requires that an empirical supplementar y
dose be given.
Regards
Steve
=Steve Duffull
http://www.uq.edu.au/pharmacy/index.html?page=31309
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)