Incidence and Risk Factors of Hypokalemia in Tazobactam/Piperacillin-administered Patients

Tazobactam/piperacillin (TAZ/PIPC) is a useful antimicrobial agent with broad antibacterial activity. Hypokalemia is considered a rare side effect of TAZ/PIPC; however, it may occur more often than previously thought. In this study, hypokalemia frequency and risk factors were examined in 420 patients treated with TAZ/PIPC. Our results demonstrated that the hypokalemia incidence was 24.8% (grade 1-2: 18.3%, grade 3-4: 6.4%). In addition, multivariate analysis revealed that age [odds ratio 1.057, 95% confidence interval 1.024-1.090, cutoff value 80.5 years] is a risk factor. Although the "Daily dosage/creatinine clearance" was not significant in multivariate analysis, univariate analysis indicated it be to be significant, with a cutoff value of 294.9 mg/mL/min. Furthermore, a "body mass index of 19.7 kg/m2 or higher", "serum potassium level before administration of 3.95 mEq/L or more", and "no empirical treatment for administration purposes" appeared to prevent the hypokalemia development. Overall, the hypokalemia incidence rate in TAZ/PIPC-administered patients was as high as 20%, with patients aged >80.5 years considered a high-risk group. Thus, careful monitoring of potassium levels in patients treated with TAZ/PIPC, particularly those aged >81 years, is warranted.