True about esmolol is: a) It is a cardioselective β–blocker b) It increases airway resistance c) It causes tachycardia d) Its t 1/2 is 4 hrs e) It has negative inotropic activity

Esmolol is an ultrashort acting β-blocker (t1/2 < 10 min.) It is inactivated by esterases in blood. β-blocker decreases heart rate and force of contraction (negative inotropic action). Beta blockers can precipitate or aggravate CHF. Selective beta 1 blocker and are less likely to cause bronchoconstriction, thus do not increase airway resistance.