WordNet (r) 3.0 (2006):

take charge
    v 1: assume control [syn: take hold, take charge, take
         control]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "take charge":
   active, acute, aggressive, animated, arrogate, assume,
   assume command, be able, be up to, brisk, can, can do, cut it,
   cut the mustard, dynamic, energetic, enterprising, enthusiastic,
   forceful, forcible, full of pep, go-go, hack it, hearty, impetuous,
   incisive, intense, keen, kinetic, lively, living, lusty, make it,
   make the grade, may, mettlesome, mount the throne, peppy,
   possess authority, robust, seize, seize power, seize the throne,
   smacking, snappy, spanking, spirited, strenuous, strong,
   take command, take over, take the helm, take the lead, take-over,
   trenchant, usurp, vibrant, vigorous, vivacious, vivid, zestful,
   zesty, zippy