Pharmacokinetic Drug Dosing

Pharmacokinetic dosing calculators, dosing charts, and graphic dosing tools are available for aminoglycosides (amikacin, gentamicin, and tobramycin), Arixtra (fondaparinux), digoxin, lithium, theophylline, time above MIC and vancomycin. The purpose of these tools is to prevent dosing errors due to hand calculations, standardize the process, and decrease the time required to calculate an appropriate regimen. Other drug dosing calculators will be added as time permits.

The dosing tools (charts, graphics and calculators) use standard non abbreviated pharmacokinetic dosing equations for a one compartment open model. Simplified dosing equations are included below for those who wish to do hand calculations. The calculators determine the patient's creatinine clearance, dosing weight, drug clearance, volume of distribution, dose per kg of dosing weight, and appropriate dosing regimen.  Their advantage is the lack of hand calculations and easy of use. The calculators may be used to analyze serum levels too. The graphic tools are faster and easier to use than traditional programs or the calculators when serum levels are being analyzed. Ideally one can determine the initial regimen with the dosing calculator and then use the graphic tools for further dosage adjustments when pulse dosing aminoglycosides or dosing vancomycin.

The Time Above MIC calculator compares the fraction of the dosing interval that drug levels are above the  MIC for traditional short infusions of antibiotics displaying time depended killing (penicillins, cephalosporins, carbapenems) to more prolonged infusions. Please read this review for more information. You may export the file to excel and modify it as needed.

If you have questions about the dosing tools contact Marshall Pierce.

Arixtra P&T Review
Arixtra Dosing Protocol
Arixtra Monitoring Form
Arixtra Therapeutic Dosing Chart Based on Dosing Weight
Arixtra Therapeutic Dosing Chart Based on Known Serum Levels
Arixtra Prophylaxis Dosing Chart Based on Dosing Weight
Arixtra Prophylaxis Dosing Chart Based on Known Serum Levels
Arixtra Dosing Calculator and Data Fitting For Levels

Aminoglycosides Pulse Dosing: Pharmacy & Therapeutics Review
Amikacin Pulse Dosing Graphic Tool
Gentamicin & Tobramcyin Pulse Dosing Graphic Tool
Aminoglycoside Pulse Dosing Calculator and Data Fitting For Troughs
Aminoglycoside Traditional Dosing Calculator and Data Fitting for a Peak and Trough

Estimating Creatinine Clearance in Obese Patients: A Comparison of Salazar Corcoran versus Cockcroft Gault Equations. The CG equation with a fat factor of 0.4 gives values 8-15% lower than Salazar equation. Lower height (60 inches), older age (90 years old), and female gender give values around 15% lower than the Salazar equation. These equations are interchangeable, but neither has been proven to be a better estimate of creatinine clearance than using ideal body weight in the Cockcroft Gault equation. A detailed mathematical analysis demonstrating this can be found in Vancomycin Pharmacokinetic Dosing: Analysis of Patient Data & Optimization of Kinetic Parameters.


Digoxin Dosing Calculator and Data Fitting For Troughs

Lithium Dosing Calculator and Data Fitting for 12 hour post Dose Levels

Theophylline Dosing Calculator and Data Fitting For Troughs

Vancomycin Dosing: Overview of Dosing Charts,  Dosing Chart Part I & Part II
Effects of Vancomycin Volume of Distribution on Prediction Accuracy Data Table or Graphics for Q12H, Q16H, Q24H for an explanation see Vancomycin Dosing: Overview of Dosing Charts
Vancomycin Dosing for High Flux Dialysis
Vancomycin Dosing Calculator and Data Fitting For Troughs
Vancomycin Pharmacokinetic Dosing: Analysis of Patient Data & Optimization of Kinetic Parameters

Patient Pharmacokinetic Monitoring Form, Simplified Dosing Equations & Daily Notes Form 

Time Above MIC Calculator (fraction of dosing interval above MIC for drugs given by intermittent infusion)