This report presents a case of a potential pharmacokinetic drug-drug interaction (DDI) between fluconazole (FLU) and vancomycin (VCM) in a patient who underwent hepatobiliary surgery and biliary drainage. The patient was receiving treatment with vancomycin, meropenem, and fluconazole for an infectious condition. The exact effects of FLU and VCM on each other’s pharmacokinetics have not been fully explored. However, understanding the role of renal transporters (such as multidrug resistance-associated proteins, organic cation transporters, and P-glycoprotein) in the excretion of these drugs is crucial for predicting drug disposition and optimizing dosage. Inhibiting these transporters is often the underlying mechanism of drug interactions. Pharmacokinetic monitoring showed that when FLU was co-administered with VCM, the trough concentration and half-life of VCM increased unexpectedly compared with when VCM was given alone. These alterations in pharmacokinetic parameters suggest a possible DDI between FLU and VCM. Therefore, caution should be exercised when these drugs are used together, and VCM trough concentrations should be carefully monitored to minimize toxicity risk.
This study assesses the risk of severe hyperlactatemia (defined as lactate levels > 4 mmol/L) in patients undergoing chronic low-dose aspirin (ASP) therapy and estimates the strength of this association. A case-crossover design was employed, in which individuals who experienced the outcome also served as their own controls, with exposure evaluated during a pre-event period. Additionally, a person-day–based analytical approach was used to compare exposure between case and control periods. Among the case group (ASP exposed/unexposed), the distribution was 127/578, while in the control group it was 547/3,968, yielding an odds ratio (OR) of 1.6 (95% CI: 1.29–1.97; z = 4.31; P < 0.0001). The findings suggest a modest association between low-dose aspirin use (100 mg/day) and elevated lactate levels, particularly in its primary indication for secondary prevention of vascular ischemic events. Although the observed risk is relatively low (OR = 1.6), clinical monitoring is advisable, especially when aspirin is co-administered with agents sharing similar toxicological profiles. Incorporating lactate level assessment into therapeutic management plans may enhance patient safety and therapeutic outcomes.