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Hello,
I am searching the literature for alternative equations for the
estimation of ideal body weight to use in the calculation of estimated
Creatinine Clearance and to use with population estimates of volume of
distribution for aminoglycosides, etc. Thanks in advance for any information
provided...
-DT-
Del Tippey R.Ph., M.S.S.M.
DCH Regional Medical Center
801 University Blvd. E.
Tuscaloosa,AL 35405
1-205-759-7310
djtippey.at.dbtech.net
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Del !
I suggest you read a consensus document that was posted recently on the
pulsing dosing of aminoglycosides. In an appendix at the end of this
document you will find the desired equations and more. The address is:
http:/pharm.cpb.uokhsc.edu/pkin/consensus/oda-cd3.html
Good luck
*************************************
Nasr Anaizi, PhD RPh
Univ of Rochester Med Cntr
nanaizi.-at-.pharmacy.urmc.rochester.edu
*************************************
At 10:41 AM 2/24/97 -0600, you wrote:
>PharmPK - Discussions about Pharmacokinetics
> Pharmacodynamics and related topics
>
>Hello,
>
> I am searching the literature for alternative equations for the
>estimation of ideal body weight to use in the calculation of estimated
>Creatinine Clearance and to use with population estimates of volume of
>distribution for aminoglycosides, etc. Thanks in advance for any information
>provided...
>
>-DT-
>Del Tippey R.Ph., M.S.S.M.
>DCH Regional Medical Center
>801 University Blvd. E.
>Tuscaloosa,AL 35405
>1-205-759-7310
>djtippey.at.dbtech.net
>
>Also see: http://www.cpb.uokhsc.edu/pkin/pkin.html
>
Back to the Top
The following equation can be use :
LBW (males) = 50 kg + 2.3 kg per inch over 5 ft
LBW (females) = 45.5 kg + 2.3 kg per inch over 5 ft
Please also see page 420, Applied biopharmaceutics and
pharmacokinetics Leon Shargel and Andrew B.C. Yu for detail
Masood
______________________________ Reply Separator
_________________________________
Subject: Ideal Body Weight Calculations
Author: PharmPK.aaa.pharm.cpb.uokhsc.edu at Internet
Date: 2/24/97 7:53 PM
PharmPK - Discussions about Pharmacokinetics
Pharmacodynamics and related topics
Hello,
I am searching the literature for alternative equations for the
estimation of ideal body weight to use in the calculation of estimated
Creatinine Clearance and to use with population estimates of volume of
distribution for aminoglycosides, etc. Thanks in advance for any information
provided...
-DT-
Del Tippey R.Ph., M.S.S.M.
DCH Regional Medical Center
801 University Blvd. E.
Tuscaloosa,AL 35405
1-205-759-7310
djtippey.-at-.dbtech.net
Also see: http://www.cpb.uokhsc.edu/pkin/pkin.html
Back to the Top
At 10:41 AM 2/24/97 -0600, you wrote:
>PharmPK - Discussions about Pharmacokinetics
> Pharmacodynamics and related topics
>
>Hello,
>
> I am searching the literature for alternative equations for the
>estimation of ideal body weight to use in the calculation of estimated
>Creatinine Clearance and to use with population estimates of volume of
>distribution for aminoglycosides, etc. Thanks in advance for any information
>provided...
>
>-DT-
>Del Tippey R.Ph., M.S.S.M.
>DCH Regional Medical Center
>801 University Blvd. E.
>Tuscaloosa,AL 35405
>1-205-759-7310
>djtippey.at.dbtech.net
>
The following is the equation that I always use. It has been verified in
infants, children and adults.
BSA = (Wt in Kg)**0.5378 * (Ht in cm)**0.3964 * 0.04265 m2
Haycock GB, Schwartz GJ, Wisotsky DH: Geometric method for measuring body
surface area: a height-weight formula validated in infants, children, and
adults. Journal of Pediatrics 1978;93:62-66.
*******************
Ronald A. Herman, Ph.D. S525 College of Pharmacy
Asst. Prof., College of Pharmacy Iowa City, IA 52246
Clinical & Administrative Pharmacy Division (319) 335-8765
(319) 353-5646 (Fax)
http://rherman.pharmacy.uiowa.edu Ronald-A-Herman.-at-.uiowa.edu
*******************
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Thank you for the reply, but are you aware of equations that estimate ideal
body weight for patients that fall outside this range -i.e. height < 60
inches, below knee amputees, etc. Thanks in advance...
-DT-
Del Tippey R.Ph., M.S.S.M.
DCH Regional Medical Center
801 University Blvd. E.
Tuscaloosa,AL 35405
1-205-759-7310
djtippey.aaa.dbtech.net
Back to the Top
Isn't there a misprint in your formula?
In Gibaldi, M., Biopharmaceutics and Clinical Pharmacokinetics.
Philadelphia: Lea & Febiger, 1984, p. 211 we find almost the same
formula except the coefficient:
BSA(m2)=WT^0.5378*HT^0.3964*0.024265
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Thanks for the info. Also thanks for the info you sent earlier regarding
Vancomycin Vd. I'm going to check out this reference. BTW, does the ** refer
to exponent?
Del Tippey R.Ph., M.S.S.M.
DCH Regional Medical Center
801 University Blvd. E.
Tuscaloosa,AL 35405
1-205-759-7310
djtippey.-at-.dbtech.net
Back to the Top
Yes, the last term should be 0.024265.
Also, the incorrect response was sent, my full message (but inadvertantly
not sent) was:
Ideal body weight (18 years of age and older):
Males: 50 Kg + (2.3 Kg for each inch over 5 feet)
Females: 45.5 Kg + (2.3 Kg for each inch over 5 feet)
(Unable to find primary reference.)
Ideal body weight (Children age 1 - 18):
Under 5 feet: IBW (Kg) = (Ht in cm)**2 * 0.00165
5 feet or taller: Males: 39 Kg + (2.27 Kg for each inch over 5 feet)
Females: 42.2 Kg + (2.27 Kg for each inch over 5
feet)
Traub SL and Johnson CE: Comparison of methods of estimating
creatinine
clearance in children. Am J Hosp Pharm 1980;37:195-201.
Body surface area:
BSA (m2) = (Wt in Kg)**0.5378 * (Ht in cm)**0.3964 * 0.024265 m2
Haycock GB, Schwartz GJ, Wisotsky DH: Geometric method for measuring
body surface area: a height-weight formula validated in infants,
children, and adults. Journal of Pediatrics 1978;93:62-66.
*****************************************************************************
Ronald A. Herman, Ph.D. S525 College of Pharmacy
Asst. Prof., College of Pharmacy Iowa City, IA 52246
Clinical & Administrative Pharmacy Division (319) 335-8765
(319) 353-5646 (Fax)
http://rherman.pharmacy.uiowa.edu Ronald-A-Herman.at.uiowa.edu
*****************************************************************************
Back to the Top
>
> >I would like to examine the various BSA formulas; we are having quite a
> argument at work over this. Historically our hospital utilized the charts
> or calculators found in many texts that are based on the 1916 Annals of
> Internal Medicine formula of Dubors and Dubois. When pharmacy became more
> involved we used the numbers in our computer software package. This formula
> involves the square root..... I wish I had the facts here at home. Needless
> to say, the numbers come out different; I expect if I use the formula in
> this newsgroup I will get a third figure to work with. I am not a
> scientist, just a pharmacist, but I would like to know alot more about the
> different bsa formulas and their relationship, if any. Likewise, what
> happens to the toxicity of my chemo doses if I use one over the other. I
> guess I'm really looking to defend the software program and prove the non
> clinicians at the hospital they should stick to their areas of expertise.
For the specific area of cancer chemo you should read Reilly & Workman
Normalisation of anti-cancer drug dosage using body weight and surface
area: is it worthwhile? Canc Chemoth Pharmac 1993; 32:411-418
They cover in depth the issues you mention above. Unfortunately they do
not recognise that PK is determined by volume of distribution (as well
as other things) and they only discuss scaling that would be relevant to
decisions that rely on clearance i.e. steady state concs or AUC. See Holford
Clin Pharmacokin 1996;30:329-332 for a small amount of discussion of
volume scaling.
The bottom line is that there is almost no evidence that using BSA or
any other measure of size improves dose prediction for adults. The issue
becomes important when trying to scale adult doses for paediatric use.
--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, Private Bag 92019, Auckland, New Zealand
email:n.holford.-a-.auckland.ac.nz tel:+64(9)373-7599x6730 fax:373-7556
http://www.phm.auckland.ac.nz/Staff/NHolford/nholford.html
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)