CASE REPORTS Potential Subtherapeutic Linezolid and Meropenem Antibiotic Concentrations in a Patient With Severe Burns and Sepsis M.-J. Hallam, MRCS,* J. M. Allen, MSc,* S. E. James, PhD, † P. M. W. Donaldson, FRC(Path),* J. G. Davies, PhD, ‡ G. W. Hanlon, PhD, † B. S. Dheansa, RCS(Plast)* Altered pharmacokinetics in patients with major burns may result in serum antibiotic concen- trations below those required to be effective against the common pathogens encountered in burns patients. The major changes in the fluid volumes of key body compartments, which occur with a large burn, may increase the apparent volume of distribution of a drug, thereby lowering its concentration when a standard dose is given. In addition, the observed increase in renal blood flow reported in burns patients, because of the change in cardiac output, may result in a higher drug clearance and a shorter elimination half-life. As a consequence, studies have rec- ommended higher doses or more frequent dosing or both for some antibiotics in patients with major burns, but data are lacking for many of the antibiotics reserved for treatment of life-threatening infections. The authors measured serum concentrations of two antibiotics, linezolid and meropenem, in an immunosuppressed patient who presented with a severe burn to determine whether therapeutic concentrations were achieved, thereby improving the likelihood of infection control. (J Burn Care Res 2010;31:207–209) Altered pharmacokinetics (PK) in patients with major burns may result in serum antibiotic concentrations be- low those required to be effective against the common pathogens encountered in burns patients. 1 The major changes in the fluid volumes of key body compartments, which occur with a large burn, may increase the appar- ent volume of distribution of a drug, thereby lowering its concentration when a standard dose is given. In ad- dition the observed increase in renal blood flow re- ported in burns patients, because of the change in cardiac output, may result in a higher drug clearance and a shorter elimination half-life. As a consequence, studies have recommended higher doses or more frequent dos- ing or both for some antibiotics in patients with major burns, 2– 4 but data are lacking for many of the antibiotics reserved for treatment of life-threatening infections. We measured serum concentrations of two antibiotics, lin- ezolid and meropenem, in an immunosuppressed pa- tient who presented with a severe burn to determine whether therapeutic concentrations were achieved, thereby improving the likelihood of infection control. CASE REPORT A 27-year-old man, injured in a caravan fire following the explosion of a gas cooker sustained burns to his face, neck, trunk, legs, and arms totaling 52% TBSA. The patient was taken to a local university hospital for assessment where his injuries necessitated intubation, ventilation, and subsequent transfer to the Queen Victoria Hospital Burn Centre. The burns were of mixed depth, and the patient was taken immediately to the operating theatre for debridement and application of Biobrane™ to his limbs and Aquacel ® Ag to the neck. Postoperatively, he was managed in the burns intensive care unit. Forty-eight hours after injury, the patient began to show signs of sepsis with pyrexia, deteriorating respiratory function, and increasing cardiovascular instability, which required fluid replacement and From the *Burns Centre, Queen Victoria Hospital, East Grinstead; † School of Pharmacy and Biomolecular Sciences, University of Brighton, and ‡ Pharmaceutical Science Division, Kings College London, United Kingdom. Address correspondence to Marc-James Hallam, BM, BSc (hons), MRCS, The Burns Centre Queen Victoria Hospital, Holtye Road, East Grinstead, West Sussex RH19 3DZ, United Kingdom. Copyright © 2010 by the American Burn Association. 1559-047X/2010 DOI: 10.1097/BCR.0b013e3181c89ee3 207