A patient taking ketoconazole and terfenadine both, is prone to -
Cardiac arrythmia
Toxicity of ketoconazole
Congestive cardiac failure
All of the above
Ans. is 'a' i.e., Cardiac arrhythmia o Terfenadine causes blockade of delayed rectifier K+ channels in the hea at higher concentration and can cause Torsades De Pointes (Polvmorph ventricular tachcardia) --> Prolonged QT interval. Drugs inhibiting the metabolism of terfenadine by inhibiting CYP3AY enzyme, can precipitate ventricular arrythmia Erythromycin, clarithromycin, itraconazole, ketoconazole.