Ultralente is not used very successfully in dogs, but has been widely used in treatment of cats. With an onset of 1-4 hours and a duration of 12-24 hours. Most cats require 2 ultralente shots a day. Ultralente absorption can be erratic, with about 20% not responding to the insulin--not even with twice-daily dosing. Most humans not using an analog intermediate or long acting insulin for basal needs are or were using either NPH or Lente on an average of twice a day.