Targeted Antibiotic Dosing Calculator

Pharmacokinetic Analysis Tool for Clinical Decision Support

Created by Nick Lonardo, PharmD & Andre Lonardo — Available for questions and feedback

Pharmacokinetic References

Cefepime

  1. Barbhaiya RH, Knupp CA, Forgue ST, et al. Pharmacokinetics of cefepime in subjects with renal insufficiency. Clin Pharmacol Ther 1990;48:268-76. [PubMed]

Piperacillin/Tazobactam

  1. Udy AA, Varghese JM, Altukroni M, et al. Subtherapeutic initial beta-lactam concentrations in select critically ill patients. Chest 2012;142(1):30-39. [PubMed]

Meropenem

  1. Kees MG, Minichmayr IK, Ganter C, et al. Population pharmacokinetics of meropenem during continuous infusion in surgical ICU patients. J Clin Pharmacol 2016;56(3):307-315. [PubMed]

Ceftazidime

  1. Georges B, Conil JM, Cougot P, et al. Ceftazidime dosage regimen in intensive care unit patients: from a population pharmacokinetic approach to clinical practice. Br J Clin Pharmacol 2012;73(4):588-596. [PubMed]

Ampicillin

  1. Blum RA, Kohli RK, Harrison NJ, et al. Pharmacokinetics of ampicillin and sulbactam coadministered to subjects with normal and abnormal renal function. Antimicrob Agents Chemother 1989;33(9):1470-1476. [PubMed]

Vancomycin

  1. Matzke GR, McGory RW, Halstenson CE, et al. Pharmacokinetics of vancomycin in patients with various degrees of renal function. Antimicrob Agents Chemother 1984;25(4):433-437. [PubMed]
  2. Rybak MJ, Le J, Lodise TP, et al. Therapeutic monitoring of vancomycin for serious MRSA infections: A revised consensus guideline. Am J Health Syst Pharm 2020;77(11):835-864. [PubMed]

Cefazolin

  1. Lavillaureix J, Gravey A, Levy J, et al. Pharmacokinetic study of cefazolin in normal subjects and patients with renal insufficiency. J Clin Pharmacol 1972;12:412-418.

Ceftolozane/Tazobactam

  1. Wooley M, Miller B, Krishna G, et al. Impact of renal function on the pharmacokinetics and safety of ceftolozane-tazobactam. Antimicrob Agents Chemother 2014;58(4):2249-2255. [PubMed]

Penicillin G

  1. Bryan CS, Stone WJ. Comparable intravascular effects of penicillin G and other antibiotics. J Clin Pharmacol 1975;15:533-535.

Cefiderocol

  1. Kawaguchi N, Katsube T, Echols R, et al. Population pharmacokinetic and pharmacokinetic/pharmacodynamic analyses of cefiderocol. Antimicrob Agents Chemother 2021;65(3):e01437-20. [PubMed]

Aminoglycoside PK

  1. Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm 1974;8:650-655.
  2. Nicolau DP, Freeman CD, Belliveau PP, et al. Experience with a once-daily aminoglycoside program administered to 2,184 adult patients. Antimicrob Agents Chemother 1995;39(3):650-655. [PubMed]

General PK Equations

  1. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16(1):31-41. [PubMed]
  2. Grubb A, Nyman U, Bjork J. Simple cystatin C-based prediction equations for glomerular filtration rate. Clin Chem 2005;51(9):1420-1431.
  3. Levey AS, Bosch JP, Lewis JB, et al. A more accurate method to estimate glomerular filtration rate from serum creatinine. Ann Intern Med 1999;130(6):461-470.
  4. Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm 1974;8:650-655.

Important Clinical Disclaimer

This calculator is intended for educational and clinical decision support purposes only. It is not a substitute for professional medical judgment. All dosing decisions should be made by qualified healthcare professionals who have access to complete patient information, including but not limited to medical history, current medications, allergies, and clinical status.

Pharmacokinetic calculations are based on population-derived parameters and may not accurately predict drug concentrations in individual patients. Therapeutic drug monitoring should be used when available. The developers assume no liability for clinical decisions made using this tool.

Privacy: All data is processed locally in your browser. No patient information is transmitted, stored, or saved to any server. Data is cleared when you close or refresh this page.

Patient Specific Data

Clinical judgment value used for dosing

Measured Creatinine Clearance

12hr=720, 24hr=1440
Measured CrCL (Uncorrected) -- mL/min
Measured CrCL (BSA Corrected) -- mL/min/1.73m²

Calculated Dosing Values

BMI -- kg/m²
Ideal Body Weight -- kg
Adjusted Body Weight -- kg
BSA -- m²
Modified Cockcroft-Gault -- mL/min
Cystatin C (Grubb) -- mL/min/1.73m²
Cystatin C (Larsson) -- mL/min/1.73m²
MDRD (6-variable) -- mL/min/1.73m²
CrCL Corrected for BSA -- mL/min/1.73m²

Renal Function Comparison

Antibiotic Pharmacokinetic Analysis

Dosing Parameters

Protein Binding: 16%
Vd: 0.34 L/kg (adj BW)
Target: fT>MIC 60-70%

Pharmacokinetic Results

Daily Dose -- mg/hr
Drug CL -- L/hr
Vd -- L
K -- hr⁻¹
Half-life -- hr
CpSS (CI) -- mcg/mL
CpSS (Max) -- mcg/mL
CpSS (Min) -- mcg/mL
fCpSS (CI) -- mcg/mL
fCpSS (Max) -- mcg/mL
fCpSS (Min) -- mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

Protein Binding: 16%
Vd: 0.43 L/kg (adj BW)
Target: fT>MIC 50%
Udy Critical Care PK Model

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

Protein Binding: 5%
Vd: 0.23 L/kg (adj BW)
Target: fT>MIC 40%

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

Protein Binding: 5%
Vd: Two-compartment model
V1: 18.9 L (9.02 L if on mech vent)
Target: fT>MIC 60-70%
Georges Population PK Model

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
V1--L
V2--L
Vss--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

Protein Binding: 50%
Vd: 0.57 L/kg (CrCL≥60) or 0.83 L/kg
Target AUC/MIC: 400-600

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd--L
K--hr⁻¹
Half-life--hr
24hr AUC--mcg·hr/mL
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
AUC/MIC Target Attainment: --

First Dose Two-Level PK Assessment

K--hr⁻¹
Half-life--hr
Cmax--mg/L
Vd--L
AUC (Lin Trap)--mg·hr/L
AUC (Log Trap)--mg·hr/L
AUC (Last→∞)--mg·hr/L
Total AUC--mg·hr/L
Clearance--L/hr
Rec. Daily Dose--mg/day

AUC Profile

Steady-State Two-Level PK Assessment

K--hr⁻¹
Half-life--hr
C1 (Trough)--mg/L
Cmax--mg/L
Vd--L
AUC (Lin Trap)--mg·hr/L
AUC (Log Trap)--mg·hr/L
AUC (Interval)--mg·hr/L
24hr AUC--mg·hr/L
Clearance--L/hr

AUC Profile

Dosing Parameters

Protein Binding: 5%
Vd: 0.21 L/kg (adj BW)
Ke = 0.022 + 0.0028×CrCL

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

Protein Binding: ~20%
Vd: 0.28 L/kg (adj BW)

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

Protein Binding: 16%
Vd: 0.22 L/kg (adj BW)

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

1 MU = 625 mg
Protein Binding: 65%
Vd: 0.41 L/kg (adj BW)

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL
fCpSS (CI)--mcg/mL
fCpSS (Max)--mcg/mL
fCpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Dosing Parameters

Protein Binding: ~58%
Vd1: 7.78 L (Central)

Pharmacokinetic Results

Daily Dose--mg/hr
Drug CL--L/hr
Vd1--L
K--hr⁻¹
Half-life--hr
CpSS (CI)--mcg/mL
CpSS (Max)--mcg/mL
CpSS (Min)--mcg/mL

Concentration-Time Profile

Total Concentration
Free Concentration
MIC Target
fT>MIC: --

Continuous Renal Replacement Therapy (CRRT)

CRRT Parameters

Non-renal clearance component

CRRT Clearance Results

L/hr

CL of ABX (CRRT) -- L/hr
CL Non-Renal -- L/hr
Total CL (CRRT + NR) -- L/hr

mL/min

CL of ABX (CRRT) -- mL/min
CL Non-Renal -- mL/min
Total CL (CRRT + NR) -- mL/min

Aminoglycoside Two-Level PK Assessment

First Dose Two-Level PK (Gent / Tobra / Amikacin)

K--hr⁻¹
Half-life--hr
Cmax--mg/L
Vd--L
AUC (Lin Trap)--mg·hr/L
AUC (Log Trap)--mg·hr/L
AUC (Last→∞)--mg·hr/L
Total AUC--mg·hr/L
Clearance--L/hr
CL--mL/min

AUC Profile

Steady-State Two-Level PK (Gent / Tobra / Amikacin)

K--hr⁻¹
Half-life--hr
C1 (Trough)--mg/L
Cmax--mg/L
Vd--L
AUC (Lin Trap)--mg·hr/L
AUC (Log Trap)--mg·hr/L
AUC (Interval)--mg·hr/L
24hr AUC--mg·hr/L
Clearance--L/hr
CL--mL/min

AUC Profile

Hartford Nomogram (Extended-Interval Dosing)

Plot the first post-dose level on the nomogram to determine dosing interval. Based on 7 mg/kg extended-interval aminoglycoside dosing.