Effect of tyramine in migraine: a double-blind study.
The incidence of headache and changes in the EEG after tyramine were studied in 25 migrainous patients in a double-blind placebo-controlled investigation. There were three groups of patients: the first had migraine alone, the second had migraine and epilepsy, and the third had migraine which was precipitated by food substances containing tyramine. Psychological tests showed that all the patients were more neurotic, more introverted, and more obsessional than normal subjects. Headache occurred in 12 of 50 patient sessions and 10 of these occurred in the group with dietary precipitated migraine. In this group, however, headache followed tyramine alone in only two patients. The remaining eight headaches occurred in two patients after placebo alone, and in three after both test capsules. The EEG was activated after tyramine, but not after placebo, in 11 of the 15 patients with migraine and epilepsy, and dietary precipitated migraine. This effect was observed, however, in only two of the 10 patients with classical migraine alone. There was no relation between the occurrence of headache and EEG activation. Although there was no significant relationship between tyramine ingestion and the occurrence of headache, the EEG changes observed during the study support the hypothesis that tyramine has an action on the central nervous system in some migrainous subjects.