Acepromazine inhibits hERG potassium ion channels expressed in human embryonic kidney 293 cells

Comparison of the effects of propofol and alfaxalone on the electrocardiogram of dogs, with particular reference to QT interval

Cardiac electrical activity is often altered by administration of anesthetic drugs. While the effects of propofol in this regard have previously been described in dogs, to date, there are no reports of the effect of alfaxalone. This study investigated the impact of both propofol and alfaxalone on the ECG of 60 dogs, after premedication with acepromazine and methadone. Heart rate increased significantly in both groups. The PR and QRS intervals were significantly increased following propofol while with alfaxalone the QRS duration was significantly increased and ST segment depression was observed. The QT and JT interval were significantly shorter following induction with alfaxalone, but, when corrected (c) for heart rate, QTc and JTc in both groups were significantly greater following induction. When comparing the magnitude of change between groups, the change in RR interval was greater in the alfaxalone group. The change in both QT and JT intervals were significantly greater following alfaxalone, but when QTc and JTc intervals were compared, there were no significant differences between the two drugs. The similarly increased QTc produced by both drugs may suggest comparable proarrhythmic effects.

Impact of antipsychotics and antidepressants drugs on long QT syndrome induction related to hERG channel dysfunction: A systematic review

PURPOSE

QT prolongation is one of the main unwanted cardiac effects caused by drugs, such as anti-psychotics and anti-depressants, inducing mainly via hERG channel dysfunction. The precise and underlying mechanism of adverse effects on hERG channel are still indecisive, but these effects limit their use in patients with cardiac risk factors. The aim of this review was studying mechanism of Long-term QT syndrome induction via hERG channel dysfunction by these Drugs.

METHOD

Search was performed in PubMed, and Scopus. All human, animals, and cell lines studies, English and full text publications were included. Among 1280 papers, 23 studies were eligible for more assessments. Quality of studies cheeked by two researchers independently.

KEY FINDING

most of studies were done on anti-psychotic drugs, especially typical class. Most used investigated method to long-term QT induction was patch clamp.

SIGNIFICANCE

results suggests in susceptible cases with heart risk factors, these drugs should be taken with caution and monitored.

Compounds commonly used in equine medicine inhibits the voltage-gated potassium channel Kv11.1

BACKGROUND

The voltage-gated K⁺-channel K_v11.1 has a central role in cardiac repolarization. Blockage of K_v11.1 has been linked to severe cardiovascular side effects, such as acquired long QT syndrome (aLQTS), torsade de pointes arrhythmia and sudden cardiac death (SCD). K_v11.1 is susceptible to unspecific drug interactions due to the presence of two aromatic amino acids residing in the inner vestibule of the pore. These aromatic residues are also present in the equine orthologue of K_v11.1. This suggests that equine K_v11.1 may also be prone to high-affinity block by a range of different chemical entities, which potentially could cause severe cardiac side effects and SCD in horses.

AIM

To screen a series of commonly used drugs in equine medicine for interaction with K_v11.1.

METHODS

High-throughput screening of selected compounds on human K_v11.1 expressed in a mammalian cell line was performed using an automated patch clamp system, the SyncroPatch 384PE (Nanion Technologies, Munich, Germany). Results were validated on equine K_v11.1 expressed in CHO-K1 cells by manual patch clamp.

RESULTS

Acepromazine maleat (IC₅₀ = 0.5 μM) trimethoprim (IC₅₀ = 100 μM), diphenhydramine hydrochloride (IC₅₀ = 2 μM) and cyproheptadine hydrochloride (IC₅₀ = 1.84 μM) inhibited equine K_v11.1 current at clinically relevant drug concentrations.

CONCLUSION

The results suggest that drug interaction with K_v11.1 can occur in horses and that some drugs potentially may induce repolarization disorders in horses.