Monitoring Serum Bisoprolol Concentrations in Patients With Heart Failure With Reduced Ejection Fraction: Results of a Pilot Study From Routine Health Care.

Bisoprolol is a second-generation, highly selective beta-1 adrenergic receptor antagonist with various beneficial effects in patients with heart failure. Interindividual variability in response to bisoprolol is known, and finding the optimal dose for individual patients with heart failure is still challenging. This pilot study included patients treated with bisoprolol for chronic heart failure with reduced ejection fraction. Between November 2022 and November 2023, one to six blood samples were collected from these patients to determine the trough serum concentration of bisoprolol. At the same time, the values of selected clinical variables were recorded. Bisoprolol concentrations ranged from 1.1 to 65.0 μg/L and correlated with both the daily dose and the dose per kilogram of body weight. However, wide variability in measured serum concentrations of bisoprolol was observed at the same daily dose and in apparent weight-adjusted clearance. Patients classified as NYHA III-IV received a 33% higher dose per kilogram of body weight than patients in NYHA I-II but achieved 165% higher serum concentrations of bisoprolol. An inverse correlation was found between diastolic blood pressure and dose per kilogram of body weight, and a positive correlation between N-terminal pro-B-type natriuretic peptide and both dose per kilogram of body weight and serum bisoprolol concentration. A wide variability in patients' serum concentrations of bisoprolol achieved after taking the same dose has been observed. A significantly higher concentration-to-dose ratio and a significantly lower weight-adjusted apparent clearance were demonstrated in patients with reduced cardiac function, reduced renal function, and taking the combination with amiodarone. These patients may be more prone to overdose with bisoprolol.