According to the leaflet, the Terifrac Pen is used once daily, and each 3 mL cartridge is intended to last about 28 days. After 28 days, the pen should be discarded, even if some medicine remains. It delivers a fixed dose of 20 micrograms per day, which the patient cannot adjust. Any change in dose or treatment duration must be made only under a doctor’s supervision, as this medication is meant to be used carefully under medical guidance.