Dihydroergotamine for early and late treatment of migraine with cutaneous allodynia: an open-label pilot trial. 
To explore whether dihydroergotamine (D.H.E. 45) is equally effective and safe for migraine with allodynia, when administered either early or late in an attack.  Central sensitization may account for the extracranial tenderness and cutaneous allodynia that can occur with migraine.  Once allodynia is established, triptans are less effective.  Dihydroergotamine is often effective for patients whose refractory headaches have failed prior triptan therapy.  In this single-center, open-label pilot trial, patients with episodic migraine associated with cutaneous allodynia were treated on 2 occasions with dihydroergotamine 1.0 mg intramuscularly.  One attack was treated within 2 hours (early) and a second attack at 4 hours (late) after the onset of throbbing pain.  Headache pain and any associated symptoms, subjective cutaneous allodynia, and mechanical (brush) allodynia were assessed.  All data were analyzed using the Fisher's exact test.  Thirteen patients met the entry criteria; however, data from only 9 patients, those who completed treatment for 2 migraine attacks, were used to evaluate the efficacy and safety of dihydroergotamine.  Whether they took dihydroergotamine early or late in the attack, most patients (>55%) had headache relief within 2 hours, and at least 44% of patients achieved headache-free status by 8 hours postdose.  Subjective cutaneous allodynia started to decline after 30 minutes postdose in the early treated group and after 120 minutes postdose in the late-treated group.  Brush allodynia began to decline after 15 minutes postdose in the early treated group and after 90 minutes postdose in the late-treated group.  Six of 9 patients (67%) reported at least 1 adverse event.  The results of this pilot trial provide proof of concept for the headache-relief benefit of dihydroergotamine in patients with migraine headache and allodynia.  A large, placebo-controlled trial of dihydroergotamine in allodynic patients is warranted.