Intravenous valproate aborts glyceryl trinitrate-induced migraine attacks: a clinical and quantitative EEG study.

We evaluated EEG changes and pain relief in migraineurs with glyceryl trinitrate (GTN)-induced attacks treated with intravenous sodium valproate (iSVP). EEG frequency analysis was performed in 45 migraineurs without aura and in 19 controls at baseline, at the time of maximum GTN-induced headache, and 30 min after 300 mg iSVP. Nineteen migraineurs presented early specific headache (migraine identical to spontaneous attacks; MSp) and 26 presented early non-specific headache (MnSp). During attacks in MSp there was an increase of theta [16.6% (14.8-19.3) to 19.4% (17.4-22.1), P = 0.02] and delta activity [3.6% (3.1-4.4) to 5.4% (3.9-6.5), P = 0.009], whereas there was no decrease in alpha [41.4% (36.2-45.1) to 39.7% (34.7-44.8)] or beta activity [37.6% (34.7-40.3) to 35.1% (33.5-38.8)]. iSVP reduced migraine from severe/moderate to mild/no pain in 17 (90%) MSp patients, and was associated with reversion of the slow rhythmic activity to baseline levels [theta 16.9% (14.6-18.9); delta 3.2% (3-4.1)]. There was no change in EEG frequency activity after administration of GTN or iSVP in controls and in MnSp. iSVP is well tolerated and effective in treating GTN-induced migraine in migraineurs without aura, and appears to restore the disturbances of cortical electrogenesis associated with these attacks.