This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hypeension, Arrhythmias, Dyslipidemia, Subject name: Pharmacology
Which of the following drugs when combined with erythromycin may cause ventricular arrhythmias? 
Select and explain. 
A. Tetracycline, B. Streptomycin, C. Ebastine, D. Cisapride
D: Cisapride
Answer: D: Cisapride 
Explanation: As Erythromycin is enzyme inhibitor of CYP3A4 --> concentration of drugs like cisapride, Terfenadine and Astemizole increases--> blocking the K+ channel --> QT prolongation --> ventricular arrhythmias.