Effect of piperacillin/tazobactam restriction on usage and rates of acute renal failure

A piperacillin/tazobactam (PT) restriction was initiated at our institution on 15 July 2012 requiring clinical pharmacy or infectious diseases approval for durations exceeding 72 h. A retrospective review was undertaken to determine whether this restriction decreased PT usage and/or rates of acute renal failure (ARF) (defined as a 50% increase or 0.5 mg dl(-1) increase in serum creatinine from baseline). Patients prescribed at least 1 day of PT with a creatinine clearance of ≥ 39 ml min(-1) at the time of initiation in the 3 months prior to the restriction were compared with patients in the 5 months after restriction implementation. Overall, 115 unique patients were included in the pre-implementation group and compared with 117 unique patients in the post-implementation group. The pre-implementation group received a mean of 5.22 days of PT, compared with 4.71 days in the post-implementation group (P = 0.224). Ten per cent (12/115) of patients in the pre-implementation group developed ARF compared with 9.17% (11/120) of patients in the post-implementation group (P = 0.0309). Ninety-five patients in the pre-implementation group and 91 in the post-implementation group received combination therapy with vancomycin. ARF occurred in 11.6% (11/95) of those in the pre-implementation group and 12.1% (11/91) in the post-implementation (P>0.05). Overall, 11.8% (22/186) of patients who received therapy with PT and vancomycin developed ARF, compared with 1.7% (1/56) who received PT monotherapy (P < 0.0001). This restriction resulted in a numeric reduction in the number of PT days in the post-implementation group and a significant reduction in the rate of ARF.