# Drug Dosing in Obesity Reference Table

## An evidence-based drug dosing resource

Dosing weight-based medications in obese patients can often be a tricky proposition. Most medications do not have guidelines for morbidly obesity, forcing clinicians to pursue in-depth literature searches in order to decide on a dose.

The purpose of this page is to serve as a dynamic, growing repository of evidence-based recommendations regarding medication dosing in obese patients. I would encourage you to examine each medication's cited references in order to form your own conclusions. As always, reasonable clinical judgment is required in conjunction with this information.

Lastly, if you have primary literature regarding obesity dosing for a medication that is not listed on this table, please contact me with the drug name and citation and I would be happy to add it to the list.

#### Ideal Body Weight (Devine 1974) 29

Although this equation lacks scientific basis, its easy of use at the bedside and extensive use for a variety of medical applications has made it the standard method for estimating lean body mass. Note that you may use the Ideal Body Weight online calculator, or use the equations below:

$$\\Ideal\;BW\;(men)\; = 50 + 2.3*(height\;over\;60\;inches) \\Ideal\;BW\;(women)\; = 45.5 + 2.3*(height\;over\;60\;inches)$$

#### Lean Body Weight (LBW2005) 30

LBW2005 is an accurate, validated method of measuring the lean mass of an obese patient. The equation is less commonly used than the Devine 1974 equation,29 but is more accurate. Note that you may use the LBW2005 online calculator, or use the equations below:

$$\\ LBW2005\;(men) = \frac{9.27*10^3*ActualBW}{6.68*10^3+(216*BMI)} \\ LBW2005\;(women) = \frac{9.27*10^3*ActualBW}{8.78*10^3+(244*BMI)}$$

#### Adjusted body weight

In obese patients, the use of ideal body weight underdoses patients, but the use of actual body weight overdoses patients. With these circumstances, an adjustment factor (usually 40%) is often used to estimate the proportion of adipose tissue that distributes a given medication. Note that you may use the adjusted body weight online calculator, or use the equations below:

$$\\AdjustedBW\; = IdealBW + (0.4*(ActualBW - IdealBW))$$

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