Once daily dosing of gentamicin has been shown to be at least as effective as and not more toxic than a multiple daily dosing regimen. Monitoring peak and trough levels with once daily dosing is generally not suitable. For most patients a nomogram is the method of choice in order to confirm or modify dosing intervals. For a daily dose of 7mg/kg/day the Hartford nomogram can be used. Gentamicin levels should be taken 6-14 hours after the start of the infusion. For a daily dose of 5mg/kg/day the Urban-Craig nomogram can be used. Gentamicin levels should be taken 8-12 hours after the dose. It is essential that the time the gentamicin infusion was started and the time the sample was taken are documented accurately.
Monika Sznura, Regional Medicines Information Pharmacist , Midlands and East Medicines Advice Service (East Anglia site) Published