Population pharmacokinetic/pharmacodynamic modelling of nifekalant in healthy Chinese volunteers

Is nifekalant more effective than amiodarone in improving the clinical outcomes of catheter ablation in patients with persistent atrial fibrillation?

Background

Traditionally, amiodarone or electrical cardioversion was used if radiofrequency catheter ablation (RFCA) could not terminate atrial fibrillation during the procedure in patients with persistent atrial fibrillation (PeAF).

Objective

To investigate whether the nifekalant instead of amiodarone during RFCA improve procedure outcomes in patients with PeAF.

Methods

This study enrolled patients with PeAF who failed to achieve cardioversion after initial ablation at our center between January 2020 and December 2022. These patients were classified into the nifekalant (N) group and the amiodarone (A) group. And patients were followed for 1 year to evaluate long-term success rates. Subgroup analyses and the logistic regression analyses were performed.

Results

The study comprised 300 participants and included N (n = 121) and A (n = 179) groups. Following propensity score matching (PSM), 101 participants were in each group. Within the N and A groups, 57(56.44 %) and 19(18.81 %) cases successfully terminated AF, 45 (44.56 %) and 15(14.85 %) cases achieved conversion to atrial tachycardia (P < 0.001), respectively. The ventricular tachycardia was observed in only one case in the N group (P > 0.05). The follow-up results demonstrated that one-year success rates were 63.37 % and 49.50 % for the N and A groups (P < 0.05).

Conclusion

For patients with PeAF that persists after initial catheter ablation, compared to amiodarone, administration of nifekalant could convert atrial fibrillation into atrial tachycardia, following by target ablation, has the potential to improve the procedure outcomes.

Population pharmacokinetic/pharmacodynamic modeling of nifekalant injection with varies dosing plan in Chinese volunteers: a randomized, blind, placebo-controlled study

Nifekalant hydrochloride is a class III antiarrhythmic agent which could increase the duration of the action potential and the effective refractory period of ventricular and atrial myocytes by blocking the K+ current. Nifekalant is used to prevent ventricular tachycardia/ventricular fibrillation. QT interval prolongation is the main measurable drug effect. However, due to the complicated dosing plan in clinic, the relationship among dosage, time, drug concentration and efficacy is not fully understood. In this study, a single-center, randomized, blind, dose-ascending, placebo-controlled study was conducted to explore the intrinsic characteristics of nifekalant injection in healthy Chinese volunteers by a population pharmacokinetic (PK)-pharmacodynamic (PD) model approach. 42 subjects were enrolled in this study and received one of three dose plans (loading dose on Day 1 (0.15, 0.3 or 0.5 mg/kg), loading dose followed by maintenance dose (0.2, 0.4 or 0.8 mg/kg/h) on Day 4) or vehicle. Blood samples were drawn for PK evaluation, and ECGs were recorded for QTc calculation at the designed timepoints. No Torsades de Pointes occurred during the study. The popPK model of nifekalant injection could be described by a two-compartment model with first-order elimination. The population mean clearance (CL) was 53.8 L/h. The population mean distribution volume of the central (Vc) and peripheral (Vp) compartments was 8.27 L and 45.6 L, respectively. A nonlinear dose-response (Emax) model well described the pharmacodynamic effect (QTc interval prolongation) of nifekalant. The Emax and EC50 from current study were 101 ms and 342 ng/mL, respectively.

Streptozotocin-Induced Hyperglycemia Affects the Pharmacokinetics of Koumine and its Anti-Allodynic Action in a Rat Model of Diabetic Neuropathic Pain

Koumine (KM), the most abundant alkaloid in Gelsemium elegans, has anti-neuropathic, anti-inflammatory, and analgesic activities; thus, it has the potential to be developed as a broad-spectrum analgesic drug. However, factors determining the relationship between analgesic efficacy and the corresponding plasma KM concentration are largely unclear. The pharmacokinetics and pharmacodynamics of KM and their optimization in the context of neuropathic pain have not been reported. We investigated the pharmacokinetics and pharmacodynamics of KM after oral administration in a streptozotocin-induced rat model of diabetic neuropathic pain (DNP) using a population approach. A first-order absorption and elimination pharmacokinetics model best described the plasma KM concentration. This pharmacokinetic model was then linked to a linear pharmacodynamic model with an effect compartment based on the measurement of the mechanical withdrawal threshold. KM was rapidly absorbed (time to maximum plasma concentration: 0.14–0.36 h) with similar values in both DNP and naïve rats, suggesting that DNP did not influence the KM absorption rate. However, the area under the curve (AUC_0–∞) of KM in DNP rats was over 3-fold higher than that in naïve rats. The systemic clearance rate and volume of KM distribution were significantly lower in DNP rats than in naïve rats. Blood glucose value prior to KM treatment was a significant covariate for the systemic clearance rate of KM and baseline value of the threshold. Our results suggest that streptozotocin-induced hyperglycemia is an independent factor for decreased KM elimination and its anti-allodynic effects in a DNP rat model. To the best of our knowledge, this is the first study to investigate the role of DNP in the pharmacokinetics and pharmacokinetics-pharmacodynamics of KM in streptozotocin-induced diabetic rats.