A method is described to prevent neural cell injury by use of a compound from a class of phosphonometyl-imidazo�1,2-a!pyrimidine-2-carboxylic acid compounds. The treatment includes administration of a compound of this class alone or in a composition in an amount effective as an antagonist to inhibit excitotoxic actions at major neuronal excitatory amino acid receptor sites. Compounds of most interest are those of the formula: ##STR1## wherein Y.sub.m is --CH.sub.2 -- or --CH.sub.2 --CH.sub.2 --; where m is one; wherein X is one or more groups attachable at one or more of the 5-, 6- and 7-ring positions of the imidazo�1,2-a!pyrimidine ring system; wherein each X and T is independently selected from hydrido, halo, alkyl, cycloalkyl, cycloalkylalkyl, haloalkyl, alkenyl, alkynyl, phenyl, benzyl, hydroxy, hydroxyalkyl, alkoxy, phenoxy, alkoxyalkyl, benzyloxy, cyano, alkanoyl, alkylthio, arylthio and amino; wherein each of R.sup.1, R.sup.2 and R.sup.6 is independently selected from hydrido, alkyl, allyl, cycloalkyl, cycloalkylalkyl, phenyl and benzyl; or a pharmaceutically-acceptable salt thereof.