Vancomycin dosing nomogram

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Background information

A fellow clinician (Nathan Fewel, PharmD, BCPS), created a quick tool that can be used to quickly generate an empiric regimen for vancomycin with just a few data points. The pdf can be downloaded here. The tool has two separate charts. The top chart targets a trough of 15-20 mcg/ml and the second dosage chart targets a trough of 10-15 mcg/ml. The tables are based on the most common elimination rate equation for vancomyin:
Ke = 0.00083 (CrCl) + 0.0044. T1/2 = 0.693/ Ke. Infusion times used (ti): 500 and 750mg = 1 hour; 1000 and 1250mg = 1.5 hours; 1500mg = 2 hours.

To help with the initial use of this tool, the author provided some great examples. Dr. Fewel has extensive experience with pharmacokinetics and the practical and clinical application of various dosing regimens.

Age

Gender

Height (in)

Weight (kg). For patients >110 kg, use adjusted BW on the nomogram to estimate V.

SCr (mg/dL).

CrCl. Use the CG equation with IBW to estimate CrCl, except for patients >110 kg (use adjusted BW), and underweight patients (use actual BW).

Predicted trough (goal trough range 15-20 mcg/mL)

70 in

90 kg

1.20

70 mL/min

1250mg q12h 35/18

68 in

120 kg (Obese; adjusted BW = 89 kg)

0.98

100 mL/min

1000mg q8h 31/18

74 in

130 kg (Obese; adjusted BW = 101 kg)

1.12

85 mL/min

1500mg q12h 34/16

67 in

60 kg (Underweight)

1.3

40 mL/min

1000mg q24h 41/17

68 in

52 kg (Underweight)

0.65

80 mL/min

750mg q12h 36/17

74 in

100 kg

0.95

Cap at 120 mL/min

1500mg q8h* 34/18

Important note: *Monitor 1500mg q8h doses closely, and consider capping initial dose at 1250mg q8h in patients >50 years old.

68 in

82 kg

0.58†

Cap at 120 mL/min

1250mg q8h 37/19*

Important note:
†Consider rounding SCr up to 0.60 mg/dL if less than 0.60 mg/dL, especially in patients greater than or equal to 65 years of age.

*When the 15-20mcg/mL nomogram predicts a trough of 19 mcg/mL, the 10-15 mcg/mL nomogram may have a lower dosage regimen with a predicted trough of 15 mcg/mL for the same V and CrCl. The lower dose may be preferred empirically in some cases based on clinical judgement.

71 in

98 kg

2.32

30 mL/min

1250mg q24h 35/18

69 in

85 kg

3.8

16 mL/min

Dose by random vanco levels when CrCl is less than 20-25 mL/min.

Note: The nomogram may also be useful for determining a new dose when calculating a patient-specific Ke based on measured trough levels. Plot the new Ke on the nomogram with the patient’s body weight.

Author:
Nathan Fewel, PharmD, BCPS
Inpatient Pharmacist
Central Texas Veterans Health Care System
Temple, Texas