Vol.63 No.4 July 2015
Antimicrobial usage density of anti-MRSA drugs: Evaluation of the state of use in our hospital
1)Department of Infection Control and Prevention, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, Japan
2)Department of Pharmacy, Hyogo College of Medicine
Abstract
Antimicrobial usage density(AUD (DDDs/1,000 bed days)) has recently been used to calculate the amount of antimicrobial drugs used, and the usefulness of evaluating therapeutic drug use against gram-negative bacteria based on the usage ratio has been reported. However, for anti-MRSA drugs, vancomycin(VCM) and teicoplanin(TEIC), deviations have been noted between the defined daily dose established by the World Health Organization(WHO-DDD) and the actual daily amount used, suggesting the necessity of reconsidering the DDD in order to evaluate the actual state of use. In the present study, we calculated the standard daily dose administered at Hyogo College of Medicine Hospital (hospital DDD), and compared the original AUD determined using the WHO-DDD and the modified AUD using the hospital DDD. The mean daily dose was calculated from the total dose of VCM and TEIC (including cases of loading doses and with changes in the dosing schedule after TDM) administered between April 2012 and March 2013, excluding patients younger than 18 years old and hemodialysis patients, and we defined it as the hospital DDD. The original AUD, modified AUD, and usage ratio of each anti-MRSA drug among all anti-MRSA drugs during the above period were calculated. VCM and TEIC were administered to 114 and 166 patients, and the mean daily doses were 1,566± 506.3 and 515± 157.3 mg, respectively. The original AUDs were 6.5± 3.4 (29.4%) and 8.4± 1.4 (38.1%), and the usage ratio of TEIC was the highest, but the modified AUDs were 8.3± 4.4 (37.7%) and 6.5± 1.1 (29.7%), respectively, and the usage ratio of VCM was the highest, clarifying that VCM accounted for about 40% of anti-MRSA drugs used in our hospital based on the modified AUD. On evaluation of the amounts of TEIC used during 3-year periods before and after the introduction of high-dose loading of TEIC (600 mg twice daily for 2 days and once on the 3rd day)(pre period: from July 2007 to June 2010, post period: from July 2010 to June 2013), the original AUD was 4.8± 2.1 in the pre period and 8.4± 2.2 in the post period, while the hospital AUD in the post period was 6.5± 1.7. Although it is unclear whether the increase in the original AUD was due to an increase in the mean daily dose or opportunity for use, the modified AUD, in which the actual amount used is considered, clarified a slight increase in use in the post period compared with that in the pre period. The results of this study confirm the usefulness of the modified AUD using the standard dose determined in hospital to evaluate the usage ratios of anti-MRSA drugs and their changes within the facility when such doses do not correspond to those targeted for AUD calculation, although it is necessary to consider possible differences between actual and calculated values.
Key word
antimicrobial usage density, defined daily dose, vancomycin, teicoplanin
Received
July 7, 2014
Accepted
March 23, 2015
Jpn. J. Chemother. 63 (4): 411-418, 2015
