Prediction Of Serum Digoxin Concentration Using Estimated Glomerular Filtration Rate In Thai Population

Serum Cystatin C as a Risk Factor for Supratherapeutic Digoxin Concentration in Elderly Patients with Heart Failure and Chronic Kidney Disease

BACKGROUND

Digoxin is primarily metabolized by the kidney, and its toxicity is strongly associated with high concentrations, particularly in elderly patients. The purpose of this study was to evaluate the predictive performance of renal function biomarkers for supratherapeutic digoxin concentrations in elderly patients with heart failure (HF) and chronic kidney disease (CKD).

METHODS

Data were retrospectively obtained from elderly patient with HF and CKD who received digoxin treatment from January 2022 and December 2022. Logistic regression was used to assess independent risk factors for supratherapeutic concentrations. The predictive performance of serum creatinine, serum cystatin C, and blood urea nitrogen on supratherapeutic concentrations was compared by receiver operating characteristic analysis.

RESULTS

A total of 115 elderly patients with HF and CKD were enrolled in our study. Supratherapeutic concentrations were detected in 49 patients. Logistic regression analysis showed that estimated glomerular filtration rate calculated by serum cystatin C [eGFRCysC, odds ratio (OR): 0.962, P = 0.006], heart rate (OR: 1.024, P = 0.040), and NYHA class (OR: 3.099, P = 0.010) were independent risk factors for supratherapeutic concentration. Cutoff value for eGFRCysC between the two groups was 41 ml/min/1.73m2. Predictive performance of serum cystatin C was further improved in patients with obesity, CKD stage 4-5, and older than 75 years compared with normal weight, CKD stage 3, and aged 60-75-year-old patients.

CONCLUSIONS

Serum cystatin C is a sensitive renal function biomarker to predict supratherapeutic digoxin concentration in elderly patients with HF and CKD.

Transplacental Therapeutic Drug Monitoring in Pregnant Women with Fetal Tachyarrhythmia Using HPLC-MS/MS

Fetal arrhythmia develops in 0.1-5% of pregnancies and may cause fetal heart failure and fetal hydrops, thus increasing fetal, neonatal, and infant mortality. The timely initiation of transplacental antiarrhythmic therapy (ART) promotes the conversion of fetal tachycardia to sinus rhythm and the regression of the concomitant non-immune fetal hydrops. The optimal treatment regimen search for the fetus with tachyarrhythmia is still of high value. Polymorphisms of these genes determines the individual features of the drug pharmacokinetics. The aim of this study was to study the pharmacokinetics of transplacental anti-arrhythmic drugs in the fetal therapy of arrhythmias using HPLC-MS/MS, as well as to assess the effect of the multidrug-resistance gene ABCB1 3435C > T polymorphism on the efficacy and maternal/fetal complications of digoxin treatment. The predisposition to a decrease in the bioavailability of the digoxin in patients with a homozygous variant of the CC polymorphism showed a probable association with the development of ART side effects. A pronounced decrease in heart rate in women with the 3435TT allele of the ABCB1 gene was found. The homozygous TT variant in the fetus showed a probable association with an earlier response to ART and rhythm disruptions on the digoxin dosage reduction. high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) methods for digoxin and sotalol therapeutic drug monitoring in blood plasma, amniotic fluid, and urine were developed. The digoxin and sotalol concentrations were determined in the plasma blood, urine, and amniotic fluid of 30 pregnant women at four time points (from the beginning of the transplacental antiarrhythmic therapy to delivery) and the plasma cord blood of 30 newborns. A high degree of correlation between the level of digoxin and sotalol in maternal and cord blood was found. The ratio of digoxin and sotalol in cord blood to maternal blood was 0.35 (0.27 and 0.46) and 1.0 (0.97 and 1.07), accordingly. The digoxin concentration in the blood of the fetus at the moment of the first rhythm recovery episode, 0.58 (0.46, 0.8) ng/mL, was below the therapeutic interval. This confirms the almost complete transplacental transfer of sotalol and the significant limitation in the case of digoxin. Previously, ABCB1/P-glycoprotein had been shown to limit fetal exposure to drugs. Further studies (including multicenter ones) to clarify the genetic features of the transplacental pharmacokinetics of antiarrhythmic drugs are needed.

Comparison of Landiolol and Digoxin as an Intravenous Drug for Controlling the Heart Rate in Patients with Atrial Fibrillation and Severely Depressed Left Ventricular Function

Clinical experience with landiolol use in patients with atrial fibrillation (AF) and a severely depressed left ventricular (LV) function is limited. We compared the efficacy and safety of landiolol with that of digoxin as an intravenous drug in controlling the heart rate (HR) during AF associated with a very low LV ejection fraction (LVEF).We retrospectively analyzed 53 patients treated with landiolol (n = 34) or digoxin (n = 19) for AF tachycardias with an LVEF ≤ 25. The landiolol dose was adjusted between 0.5 and 10 μg/kg/minute according to the patient's condition. The response to treatment was defined as a decrease in the HR of ≤ 110/minute, and that decreased by ≥ 20% from baseline.There were no significant differences between the two groups regarding the clinical characteristics. The responder rate to landiolol at 24 hours was significantly higher than that to digoxin (71.0% versus 41.2%; odds ratio: 4.65, 95% confidence interval: 1.47-31.0, P = 0.048). The percent decrease in the HR from baseline at 1, 2, 12, and 24 hours was greater in the landiolol group than in the digoxin group (P < 0.01, P = 0.071, P = 0.036, and P = 0.016, respectively). The systolic blood pressure (SBP) from baseline within 24 hours after administering landiolol was significantly reduced, whereas digoxin did not decrease the SBP over time. Hypotension (< 80 mmHg) occurred in two patients in the landiolol group and 0 in the digoxin group (P = 0.53).Landiolol could be more effective in controlling the AF HR than digoxin even in patients with severely depressed LV function. However, careful hemodynamic monitoring is necessary when administering landiolol.