The use of the compounds: ##STR1## where R is hydrogen, alkyl, alkoxy, hydroxy, alkanoyloxy, phenylalkoxy, halo or trifluoromethyl; R.sup.1 is alkyl, alkenyl or phenylalkyl; R.sup.2 is hydrogen, alkyl, phenylalkyl, alkenyl, alkynyl, thienylalkyl or furylalkyl; n is one of the integers 2, 3, 4, 5 or 6; or a pharmaceutically acceptable salt thereof, as NMDA antagonists in the treatment of convulsions and neurodegenerative disease states. The compounds in which R.sup.2 are heterocyclylalkylamines are novel and useful NMDA antagonists.