Introduction to antimicrobial dosing in kidney impairment

In patients with kidney impairment, antimicrobials or their metabolites that are excreted entirely, or in part, by the kidneys can accumulate with standard dosing, and dosage reduction may be required. For example, aminoglycosides and glycopeptides are excreted almost entirely by the kidneys, and rapidly reach toxic concentrations in patients with impaired kidney function if standard dosing regimens are used. For many commonly used beta-lactam antibiotics, a significant proportion of the dose is excreted by the kidneys; dosage adjustment may be needed in patients with impaired kidney function to avoid potentially toxic concentrations.

It is crucial that dosage adjustments are informed by the patient’s clinical status and comorbidities, the potential toxic effects of the relevant drug, and the likely consequences of underdosing. Furthermore, patients with kidney impairment can be more susceptible to drug adverse effects; specific monitoring may be required. If possible, avoid the use of nephrotoxic drugs in patients with moderate to severe kidney impairment. For further information, consult appropriate drug information texts.

The advice in this topic and the dosage modification recommendations in Antimicrobial dosage modification in kidney impairment apply to adults (people older than 18 years) with kidney impairment.

For dosage modification in children, seek expert advice. A suitable equation to estimate glomerular filtration rate (GFR) in children older than 1 year is the modified Schwartz formula.