Adverse Drug Reactions of Long-term Intravenous Antibiotics in Patients with Pyogenic Spondylitis

Objective The purpose of this study was to investigate the incidence, cause, and influence of the adverse drug reactions (ADRs) associated with long-term intravenous antibiotics in patients with pyogenic spondylitis (PS). Methods We retrospectively reviewed the medical records of 84 patients with PS who underwent intravenous antibiotic therapy in our hospital from January 2001 to December 2012. ADRs were categorized to drug eruption, acute renal failure (ARF), hematologic toxicity, toxic hepatitis, pseudomembranous colitis (PMC), drug fever, and neuronal toxicity. Incidence and onset time of each ADR after antibiotic therapy were analyzed with the incidence of ADRs according to types of antibiotics. Results ADRs occurred in 38 of the 84 patients (incidence: 45.2%). The use of antibiotics was longer in the patients with ADRs (62.7 days) than in the patients without ADRs (44.3 day). The incidence of drug eruption, ARF, hematologic toxicity, toxic hepatitis, PMC, drug fever, and neuronal toxicity were 22.6, 11.9, 11.9, 10.7, 7.1, 3.6%, and 1.2%, respectively. The duration of antibiotics administration was related to the occurrence of PMC (p=0.001). ADRs were more common in patients treated by glycopeptides including vacomycin and teicoplanin. Conclusion The incidence of ADRs due to long-term intravenous antibiotics was as high as 45.2% in patients with PS. Therefore, we speculate that the possibility of delayed ADRs should be considered after long-term use of the antibiotics. Furthermore, close observation is mandatory to identify and treat ADRs promptly, even though PS revealed the improvement after antibiotic therapy.