Long-term impact of therapeutic drug monitoring on the risk of hypoglycemia in HOCM patients on cibenzoline therapy
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OBJECTIVE: The purpose of this study was to evaluate the long-term impact of therapeutic drug monitoring (TDM) services on the risk of hypoglycemia in cibenzoline therapy. In addition, we evaluated the impact of changes in clinical setting or patient background on the risk of hypoglycemia in patients receiving cibenzoline. METHODS: TDM services for cibenzoline have been performed at the Japan National Cerebral and Cardiovascular Center since March 1998. A case-control study was performed from September 2012 to February 2013, and the calculated risk of hypoglycemia associated with cibenzoline use was compared with data from our previous studies, which were performed ~ 15 years ago. RESULTS: A significantly increased risk for hypoglycemia was observed for users of cibenzoline (adjusted OR: 2.6; 95% CI: 1.5 - 4.7). In an additional analysis, the calculated risk was slightly reduced (adjusted OR; 2.1, 95% CI; 1.1 - 3.8) and hypertrophic obstructive cardiomyopathy (HOCM) was identified as a possible risk factor for hypoglycemia (adjusted OR: 4.7, 95% CI: 1.8 - 12.3). There was a significant difference in the mean level of cibenzoline between outpatients with and without HOCM (360.5 ± 166.9 ng/mL vs. 276.4 ± 136.3 ng/mL). An inverse relationship was observed between the percentage of outpatients whose cibenzoline serum level had been measured and their risk of hypoglycemia. CONCLUSIONS: Consistent TDM services for cibenzoline have contributed to a reduced risk of hypoglycemia associated with cibenzoline therapy. Patients with HOCM have a higher risk of developing hypoglycemia. Clinicians should therefore carefully monitor serum glucose levels in patients with HOCM taking cibenzoline.
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