Monitoring and dosing of aminoglycosides: starting dose
Monitoring and dosing of aminoglycosides: starting dose
The required dose will depend on the volume of distribution and renal clearance, which are related in a general way to lean (or ideal) body weight; therefore doses are quoted in terms of mg/kg. Renal function is the main consideration, since elimination of aminoglycosides is by renal excretion. Creatinine clearance (CrCl) can be approximated in adults using the modified Cockcroft-Gault formula.
You may wish to use our automatic creatinine clearance and ideal body weight calculators.
A guide to calculating creatinine clearance in children is shown in Table 2.32.
Initial doses of aminoglycosides for patients with normal renal function are given in Table 2.25. For patients with impaired renal function, doses should be reduced (ie use the dose adjustment method, see Table 2.26) or the dosing interval lengthened (ie use the interval adjustment method, see Table 2.27). Use ideal body weight if actual weight is more than 20% over ideal body weight (see Table 2.31).
Aminoglycoside starting doses for patients with normal renal function (Table 2.25)
| Age | Starting dose [NB1] (gentamicin, tobramycin) | Starting dose [NB1] (amikacin) |
| neonates <34 weeks postconceptional age | 3 mg/kg/day | 12 mg/kg/day |
| neonates 34–44 weeks postconceptional age | 3.5 mg/kg/day | 14 mg/kg/day |
| infants and children <10 years | 7.5 mg/kg/day | 30 mg/kg/day |
| 10–29 years | 6 mg/kg/day | 24 mg/kg/day |
| 30–60 years | 5 mg/kg/day | 20 mg/kg/day |
| >60 years | 4 mg/kg/day | 16 mg/kg/day |
| any age: streptococcal and enterococcal endocarditis | 3 mg/kg/day [NB2] (use gentamicin only, in divided doses) | |
| NB1: Use ideal body weight if actual weight is >20% over ideal body weight (see Table 2.31) NB2: Lower doses are used for synergy in endocarditis (see Streptococcal endocarditis and Enterococcal endocarditis). | ||
Aminoglycoside starting doses for patients with impaired renal function: dose adjustment method (Table 2.26)
| Creatinine clearance | Starting dose [NB1] | |
| (mL/s) | (mL/min) | (% of usual recommended dose NB2, see Table 2.25) |
| >1.1 | >66 | 100% |
| 0.9–1.1 | 54–66 | 85% |
| 0.7–0.9 | 42–54 | 70% |
| 0.5–0.7 | 30–42 | 55% |
| 0.35–0.5 | 21–30 | 40% |
| <0.35 | <21 | seek specialist advice |
| NB1: For starting dose in severe sepsis, see Severe sepsis: empirical therapy (no obvious source of infection. NB2: This applies to intended once-daily dosing. | ||
Aminoglycoside starting doses and intervals for patients with impaired renal function: interval adjustment method (Table 2.27)
| Creatinine clearance | Starting dose [NB1] and proposed interval | |
| (mL/s) | (mL/min) | |
| >1.0 | >60 | 5 mg/kg every 24 hours |
| 0.7–1.0 | 40–60 | 5 mg/kg every 36 hours |
| 0.5–0.7 | 30–40 | 5 mg/kg every 48 hours |
| <0.5 | <30 | 5 mg/kg, once, then seek specialist advice |
| NB1: The starting doses are those recommended for gentamicin and tobramycin. Amikacin starting doses are 4 times those recommended. Use ideal body weight if actual weight is >20% over ideal body weight (see Table 2.31). | ||
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