The present invention relates to use of
biopterin compounds such as 4-Amino-(6R,S)-5,6,7,8-tetrahydro-L-
biopterin or 4-Amino-(6R,S)-7,8-dihydro-L-
biopterin for treating a
human patient suffering from a
disease condition or disorder that is associated with an increased glutamate level. The invention also relates to the use of such biopterin compounds in a method of treating or preventing glutamate
excitotoxicity (glutamate
storm) in a patient suffering from a condition that has the potential to result in a pathologically high glutamate level in the brain.