Source : Webster's Revised Unabridged Dictionary (1913)

Impulsively \Im*pul"sive*ly\, adv.
   In an impulsive manner.

Source : WordNet®

impulsively
     adv : in an impulsive or impetuous way; without taking cautions;
           "he often acts impulsively and later regrets it" [syn:
           {impetuously}]