True statement about fexofenadine is :: (A) It undergoes high first pass metabolism in liver, (B) Terfenadine is an active metabolite of this drug, (C) It does not block cardiac K+ channels, (D) It has high affinity for central H1 receptors
Answer is C. Fexofenadine is an active metabolite of terfenadine. It lacks K+ channel blocking property, therefore is devoid of arrhythmogenic potential. It is available as a separate second-generation H1 blocking agent.