Which screening would be used to detect a compound's effect on ion channel currents relevant to cardiac safety?

• A. QT prolongation screening
• B. Genotoxicity
• C. Cytotoxicity
• D. Receptor-ligand binding assays

Answer: (A)

The main idea is assessing a drug’s impact on the heart’s electrical activity, specifically how it affects ion channels that control ventricular repolarization. Blocking certain potassium channels in the heart, particularly the hERG channel, can slow repolarization, lengthen the QT interval on the ECG, and raise the risk of dangerous arrhythmias like torsades de pointes. So screening that directly investigates a compound’s effect on these ion channels or on the duration of the cardiac action potential is used to flag potential cardiac safety issues.

Genotoxicity looks at DNA damage, cytotoxicity at overall cell viability, and receptor-ligand binding assays examine interaction with specific targets. None of these directly measure changes in cardiac ion currents or QT interval, so they’re not the appropriate screens for this particular risk.