Metisergida como profilaxia de migranea e cefaleia em salvas, e a possível ocorrência de fibrose retroperitoneal: relato de casos

background and objectives: methysergide is a drug with proven efficacy to prevent both migraine and cluster headache, although it may predispose to fibrosis (< 1%). this study aimed at reporting two cases of primary and difficult to control headache, satisfactorily treated with methysergide, which had to be withdrawn due to suspicion of retroperitoneal fibrosis (rf). case reports: methysergide was successfully used to prevent migraine and cluster headache in a 69-year old male and in a 58-year old female, respectively, both refractory to first and second line drugs. after 24 months for the first case, and 30 months for the second case, of continuous methysergide, signs and symptoms suggesting rf were observed, such as asymmetric painless lower limbs edema in the migraine patient, and abdominal pain, sexual dysfunction and lower limbs edema in the cluster headache patient. in spite of the early negative screening for retroperitoneal edema made with normal abdominal ultrasound and ct, in the second, since signs and symptoms were progressing, we decided for methysergide withdrawal and decrease, respectively. there has been total resolution of symptoms approximately one week after such approach. conclusion: methysergide is a good option for refractory cases, but should be used with caution. withdrawing the drug every six months for approximately 4 to 8 weeks decreases the incidence of rf, in addition to clinical observation of signs and symptoms suggesting this side-effect.