Adult Weight-Based Antimicrobial Dosing Protocol
Legacy Health Modified from original work by Lindsie M. Froehlich, PharmDADULT WEIGHT-BASED ANTImicROBIAL DOSAGE ADJUSTMENT TABLE | |||||||
WEIGHT (kg) |
CrCl > 50 |
CrCl 30 – 50 |
CrCl 10 – 30 |
CrCl <10 |
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PENICILLINS |
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<80 |
1gm q6hb |
1gm q8 |
1gm q12h |
1gm q24h |
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80-139 |
2gm q6ha |
2gm q8h |
2gm q12h |
2gm q24h |
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>140 |
3gm q6ha |
3gm q8h |
3gm q12h |
3gm q24h |
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< 100 |
2gm q4h |
No dosage adjustment necessary |
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>100 |
3gm q4h |
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< 100 |
3mU q4h |
2mU q4h |
2mU q8h |
1mU q8h |
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>100 |
4mU q4h |
3mU q4h |
3mU q8h |
2mU q8h |
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< 80 |
1.5gm q6h |
1.5gm q8h |
1.5gm q12h |
1.5gm q24h |
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80 – 139 |
3gm q6h |
3gm q8h |
3gm q12h |
3gm q24h |
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>140 |
4.5gm q6h |
4.5gm q8h |
4.5gm q12h |
4.5gm q24h |
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CrCl >40 |
CrCl 20 – 40 |
CrCl <20 |
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< 100 PSE |
3.375gm q6 |
2.25gm q6h* |
2.25gm q8h* |
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4.5gm q6h |
3.375gm q6h* |
2.25gm q6h* |
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100 - 139 PSE |
3.375gm q4h |
2.25gm q4h* |
2.25gm q6h* |
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4.5gm q4h |
3.375gm q4h* |
2.25gm q4h* |
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>140 PSE |
4.5gm q6h |
3.375gm q6h* |
2.25gm q6h* |
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6gm q6h |
4.5gm q8h* |
3.375gm q8h* |
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CEPHALOSPORINS |
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< 80 |
1gm q8h |
500mg q12h* |
500mg q24h* |
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80 – 149 |
2gm q8h |
1gm q12h* |
1gm q24h* |
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>150 |
3gm q8h |
2gm q12h* |
2gm q24h* |
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< 80 |
1gm q8h |
1gm q12h |
1gm q24h |
500mg q24h* |
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80 – 149 |
2gm q8h |
2gm q12h |
2gm q24h |
1gm q24h* |
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>150 |
3gm q8h |
3gm q12h |
3gm q24h |
1gm q24h* |
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< 80 |
1gm q24h |
No dosage adjustment necessary |
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80 - 129 |
2gm q24h |
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>130 |
3gm q24h |
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< 80 |
1gm q12h |
Same dose |
1gm IV q24h |
1gm q48h |
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81 – 139 |
2gm q12h |
Same dose |
2gm q24h |
2gm q48h |
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>140 |
3gm q12h |
Same dose |
3gm q24h |
3gm q48h |
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< 100 |
1gm q8h |
1gm q12h |
1gm q24h |
500mg q24h* |
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>100 |
2gm q8h |
2gm q12h |
2gm q24h |
1gm q24h* |
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CARBAPENEMS |
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< 100 |
1gm q24h |
Same dose |
500mg q24h* |
Same dose* |
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>100 |
2gm q24h |
Same dose |
1gm q24h* |
500mg q24h* |
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< 100 |
1gm q8h |
1gm q12h |
500mg q12h* |
500mg q24h* |
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>100 |
2gm q8h |
2gm q12h |
1gm q12h* |
1gm q24h* |
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FLUOROQUINOLONES |
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< 100 |
400mg q12h |
400mg q24h |
200mg q24h* |
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101 - 139 |
600mg q12h |
600mg q24h |
300mg q24h* |
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>140 |
800mg q12h |
800mg q24h |
400mg q24h* |
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< 100 |
400mg q24h |
No dosage adjustment necessary |
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101 – 139 |
600mg q24h |
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>140 |
800mg q24h |
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>150 |
750mg q24h |
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WEIGHT (kg) |
CrCl > 50 |
CrCl 30 – 50 |
CrCl 10 – 30 |
CrCl <10 |
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MISCELLANEOUS |
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< 80 |
1gm q6h |
500mg q6h* |
250mg q6h* |
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>80 |
2gm q6h |
1gm q6h* |
500mg q6h* |
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< 80 |
600mg q8h |
No dosage adjustment necessary |
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>80 |
900mg q8h |
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Use TBW |
4-6 mg/kg q24h |
q48h |
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<80 |
400mg q24h |
200mg q24h* |
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80 - 149 |
800mg q24h |
400mg q24h* |
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>150 |
1200mg q24h |
600mg q24h* |
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< 150 |
600mg q12h |
No dosage adjustment necessary |
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>150 |
600mg q8h |
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a Use same dose q4h for endocarditis and meningitis
b Use 2 gm q4h for endocarditis and meningitis PSE = Pseudomonas infection (excluding urinary tract infection TBW: Total body weight (kg)
1. Empiric dosing should be based off of an adjusted body weight calculation using a correction factor of 40%
ABW = (TBW – IBW) x 0.4 + IBW
2. Use normal empiric dosing intervals based on renal function.
3. DO NOT use extended interval dosing in the obese population.
4. Follow peak and trough levels and adjust dose accordingly.
B. Vancomycin
1. Patients should receive an initial loading dose of 15 mg/kg based on total body weight. Maximum single dose = 3gm
2. Empiric dosing should be continued using total body weight for a total daily dose of 20 – 30 mg/kg/day with a single dose cap of 3gm.
3. Vancomycin is a time-dependent antibiotic, so shorten administration interval to q6h in patients with normal renal function if necessary to maintain serum trough >10.
4. Check trough levels regularly and adjust dose accordingly, see LHS protocol for specific trough recommendations
Obesity Dosing Quick Reference Sheet
Drug |
IBW |
TBW |
DW |
Comments |
x |
No need to adjust fixed doses for obese patients |
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x |
DW = 0.4 (TBW – IBW) + IBW |
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x |
TBW for both conventional and liposomal |
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x |
||||
x |
No need to adjust fixed doses for obese patients |
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x |
DW = 0.45 (TBW – IBW) + IBW |
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x |
||||
x |
||||
x |
||||
x |
||||
x |
||||
x |
DW = 0.4 (TBW – IBW) + IBW |
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x |
No need to adjust fixed doses for obese patients |
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x |
||||
x |
||||
x |
||||
x |
No need to adjust fixed doses for obese patients |
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x |
DW = 0.4 (TBW – IBW) + IBW |
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x |
DW = 0.4 (TBW – IBW) + IBW |
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x |
Monitor serum trough levels. Max of 3gms, increase frequency |
Abbreviations: IBW= ideal body weight, TBW=total body weight, DW=Dosing weight (use correction factor (CF)), MD=maintenance dose, LD=loading dose
BACKGROUND
In general, the volume of distribution (Vd) of hydrophilic drugs relates better to lean body mass because of poor penetration into adipose tissue and the Vd of lipophilic drugs correlates better with total body weight because of good penetration into adipose tissue8-10.
HYDROPHILIC3 |
LIPOPHILIC |
> B-lactams - Penicillins - Cephalosporins - Monobactams - Carbapenems > Daptomycin > Glycopeptides - Vancomycin > Aminoglycosides > Polymyxins |
> Aztreonam > Fluoroquinolones > Macrolides > Lincosamides > Linezolid > Tetracyclines > Tigecycline > Sulfamethoxazole/trimethoprim > Rifampin |
CREATININE CLEARANCE IN OBESITY19-27
Obese patients tend to have a higher creatinine clearance. Commonly used equations to estimate creatinine clearance( CrCl) may not be accurate predictors of clearance in the obese. The Cockcroft-Gault formula is less accurate when total body weight (TBW) is used to estimate CrCl in obese patients21.
The Salazar-Corcoran formula appears to be the more accurate of all the currently available renal function formulas9.
When a lean body weight (LBW) estimate, based on TBW and body mass index (BMI) was used in the Cockcroft-Gault equation, it provided an accurate, relatively precise estimate of CrCl27.
Salazar-Corcoran on line calculator19
Male: (137 – age) x ([0.285 x TBW] + [12.1 x height in meters]2)
51 x SCr
Female: (146 – age) x ([0.287 x TBW] + [9.74 x height in meters]2)
60 x SCr
TBW = total body weight (kg)
Cockcroft-Gault using Adjusted Body Weight (Adj. BW) on line calculator 22
Male: (140-age) x Adj. BW IBW male: [2.3 + (height(in) – 60] + 50
72 x SCr
Female: (140 – age) x Adj. BW x 0.85 IBW female: [2.3 + (height(in) – 60)] + 50
72 x SCr
Adj. BW: (TBW – IBW) x 0.4 + IBW
Cockcroft-Gault using Lean Body Weight (LBW) on line calculator 27
Male: (140-age) x LBW LBW male: 9270 x TBW
72 x SCr 6680 +216 x BMI
Female: (140-age) x LBW x 0.85 LBW female: 9270 x TBW
72 x SCr 8780 +244 x BMI
Body Mass Index (BMI) on line calculator
BMI = Weight (lbs) x 703
Height2 (in2)
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Last update 11/30/19