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For total body clearance, usually it is expressed as ml/min/kg.
However, sometimes it is given as ml/min only which makes comparison
between drugs or within a drug difficult. Is there any standard body
weights that I can use to convert between the two types of clearance
units. For example, usually an adult body weight is taken as 70kg. Is
there such a standard body weight for a man, woman, elderly, children,
etc?
Back to the Top
For total body clearance, usually it is expressed as ml/min/kg.
However, sometimes it is given as ml/min only which makes comparison
between drugs or within a drug difficult. Is there any standard body
weights that I can use to convert between the two types of clearance
units. For example, usually an adult body weight is taken as 70kg. Is
there such a standard body weight for a man, woman, elderly, children,
etc?
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The following message was posted to: PharmPK
Elfffffy wrote:
>
> PharmPK - Discussions about Pharmacokinetics
> Pharmacodynamics and related topics
>
> For total body clearance, usually it is expressed as ml/min/kg.
> However, sometimes it is given as ml/min only which makes comparison
> between drugs or within a drug difficult. Is there any standard body
> weights that I can use to convert between the two types of clearance
> units. For example, usually an adult body weight is taken as 70kg. Is
> there such a standard body weight for a man, woman, elderly, children,
> etc?
I think of a standard human having a weight of 70 kg. This implies
other standard values (e.g. age=40, sex=male, creatinine clearance=6
L/h, non-smoker, Caucasian). If you express clearance for a standard
individual then values for non-standard people differing in weight,
age, sex, renal function, smoking habit, ethnicity) can then be
predicted using suitable covariate effect models.
We have used the standard human weight of 70 kg to describe PK of drugs
in small children where we used both weight and age as covariates to
make predictions for individual children.
Nick
Anderson BJ, van Lingen RA, Hansen TG, Lin YC, Holford NHG.
Acetaminophen developmental pharmacokinetics in premature neonates and
infants: a pooled population analysis. Anesthesiology
2002;96(6):1336-45
--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New
Zealand
email:n.holford.at.auckland.ac.nz tel:+64(9)373-7599x86730 fax:373-7556
http://www.health.auckland.ac.nz/pharmacology/staff/nholford/
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