Repeated administration of dihydroergotamine for treatment of frequent migraine headaches

A method of reducing the frequency of migraine attacks in a subject who has frequent migraine headaches with or without aura, comprising:

• administering a pharmaceutical composition comprising dihydroergotamine (DHE) or salt thereof via a respiratory tract of the subject on a repeat dose schedule,
• wherein the repeat dose schedule is a chronic intermittent schedule comprising intermittent administration of multiple doses, wherein each dose is administered while the subject is experiencing a particular migraine headache and the repeat dose schedule comprises administration of (i) two or more doses within a 28-day initial administration period and (ii) no more than 2 doses within a 24-hour period and 3 doses in a 7-day period, wherein the repeat dose schedule lasts at least one month.