This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autacoids, Subject name: Pharmacology
Which of the following drugs, if given with terfena dine, can cause ventricular arrhythmias 
Select and explain. 
A. Griseofulvin, B. Ketoconazole, C. Ampicillin, D. Sparfloxacin
B: Ketoconazole
Answer: B: Ketoconazole 
Explanation: Fexofenadine:- It is the active metabolite of Terfenadine, the first nonsedating SGA that was withdrawn because of several deaths due to polymorphic ventricular tachycarida (Torsades de pointes) occurring with its higher doses or when it was coadministered with CYP3A4 inhibitors (erythromycin, clarithromycin, ketoconazole, itraconazole, etc.). mech of toxicity:- Toxicity is based on blockade of delayed rectifier K+ channels in the hea at higher concentrations. Astemizole is another SGA banned for the same reason. Ref:- kd tripathi;pg num:-166