Monitoring efficacy and nephrotoxicity of gentamicin once-daily treatment compared to every 8-hour treatment for Thai patients in Rajavithi Hospital

Abstract

The purpose of this study was to investigate the efficacy and nephrotoxicity caused by gentamicin administrated as once daily dosage regimen compared to every 8-hour regimen. Ninety-two patients with ferbrile or infectious disease were enrolled in this study. Once daily treatment provided higher efficacy than ever 8-hour treatment (p<0.05) and once-daily treatment has showed good efficacy on decrease of body temperature and white blood cell count as compared to every 8-hours treatment. For disease, once-daily treatment has showed good efficacy on UTI, FUO, sepsis and febrile neutropenia. Pseudomonas aeruginosa was good response by once-daily treatment. There was no significant difference between the two groups of treatment in the number of patients with nephrotoxicity but the serum creatinine of the patients in the every 8-hour treatment group was increase higher than in the once-daily treatment group and the creatinine clearance of the patients in the every 8-hour treatment group was decrease lower than in the once-daily treatment group so there was tendency development of nephrotoxicity in the ever 8-hour treatment group. For long term treatment of gentamicin, the every 8-hour treatment has development of nephrotoxicity faster than once-daily treatment. There were no significant difference in the distribution volume, the elimination rate constance and the half-life of gentamicin between the foreign patients and Thai patients, p<0.05. Most patients in the both groups of treatment have presented the trough serum gentamicin concentration in safety level but numbers of patient whose trough serum concentration in toxic level in the every 8-hour treatment group were higher than in the once-daily treatment group. The occurrence of nephrotoxicity may decrease if the patients are given the appropriate dose at first time. The incidence of nephrotoxicity may occur if the trough serum gentamicin concentration is higher than 2.0 mcg/ml for the every 8-hour treatment and 1.0 mcg/ml for the once-daily treatment. If the patients were closely monitored the trough serum gentamicin concentration and adjusted dosage regimen, the occurrence of nephrotoxicity will be decreased. The trough concentration correlated well with nephrotoxicity, for the every 8-hour treatment group, the trough concentration should not be higher than 2.0 mcg/ml while the trough concentration of the once-daily treatment group should not be higher than 1.0 mcg/ml. Once daily treatment required shorter duration of treatment than every 8-hour treatment (p<0.05, by unpaired t-test). The results suggest that once daily treatment could reduce health care cost and hospitalization stay.