<prompt> Which of the following drugs when combined with erythromycin may cause ventricular arrhythmias?TetracyclineStreptomycinEbastineCisapride  <response>: As Erythromycin is enzyme inhibitor of CYP3A4 -- concentration of drugs like cisapride, Terfenadine and Astemizole increases-- blocking the K channel -- QT prolongation -- ventricular arrhythmias. 