Simplification of antibiotic dose adjustments in renal insufficiency: the DREM system

Many clinicians, unassisted by reference books, are unable to make the required dose adjustment of antibiotics needed when a patient has renal insufficiency. We describe the DREM (dosing in renopathy by easy-to-use multipliers) system, which simplifies the understanding and the process of dose adjustment. DREM is a two-step process: Cockcroft and Gault estimation of creatinine clearance (CLcr) from age, sex, and serum creatinine and calculation of the adjusted dose or dosing interval by multipliers. If the normal dose is multiplied by the dose multiplier (CLcr/100) and the dosing interval by the interval multiplier (100/CLcr), the adjusted dose and interval, respectively, are obtained. Theoretical trough concentrations calculated with the DREM system correlated closely (r = 0.9) with actual concentrations obtained from doses calculated by the Hull and Sarubbi method in 23 patients. With DREM, gentamicin or tobramycin trough concentrations above 2 micrograms/ml were less likely to occur. The DREM system is a simple and easily remembered method for dose adjustments of certain anti-infective agents in renal insufficiency. Dose estimates with this method are reasonably accurate and compare favourably with other standard methods of correction.