title: Decreased serum linezolid concentrations in two patients receiving linezolid and rifampicin due to bone infections.
abstract: Methicillin-resistant Staphylococcus is a common cause of orthopaedic implant infections. In such cases, rifampicin is the antibiotic of choice, but it should not be administered alone to avoid the selection of resistant mutants. Linezolid has activity against resistant staphylococci and a high oral bioavailability; therefore, it could be a good option for combining with rifampicin. We describe 2 patients admitted to our hospital due to orthopaedic implant infections, who received combination therapy with linezolid and rifampicin. In both cases, the trough serum concentration of linezolid during rifampicin treatment was below the minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC(90)) for staphylococci, but increased after rifampicin withdrawal. This finding suggests an interaction between rifampicin and linezolid, and a possible explanation is discussed.
authors.affiliation: Department of Infectious Diseases, Hospital Clinic of Barcelona, Barcelona, Spain.
authors.forename: Irma
authors.initials: I
authors.lastname: Hoyo
authors.forename: Juan
authors.initials: J
authors.lastname: Martínez-Pastor
authors.forename: Sebastian
authors.initials: S
authors.lastname: Garcia-Ramiro
authors.forename: Consuelo
authors.initials: C
authors.lastname: Climent
authors.forename: Mercé
authors.initials: M
authors.lastname: Brunet
authors.forename: Marta
authors.initials: M
authors.lastname: Cuesta
authors.forename: Josep
authors.initials: J
authors.lastname: Mensa
authors.forename: Alex
authors.initials: A
authors.lastname: Soriano
mesh_terms: D000081:Acetamides / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D000328:Adult; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D004347:Drug Interactions; D005260:Female; D006801:Humans; D000069349:Linezolid; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010019:Osteomyelitis / Q000188:drug therapy* / Q000382:microbiology; D023303:Oxazolidinones / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D016459:Prosthesis-Related Infections / Q000188:drug therapy / Q000382:microbiology; D012293:Rifampin / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D044967:Serum / Q000737:chemistry; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D000069349:Linezolid; D012293:Rifampin