Dilantin (phenytoin) is related to the barbiturates in chemical structure, but has a five-membered ring. The chemical name is 5,5-diphenyl-2,4 imidazolidinedione.
Each teaspoonful of suspension contains 125 mg of phenytoin, USP with a maximum alcohol content not greater than 0.6 percent. Also contains carboxymethylcellulose sodium, USP; citric acid, anhydrous, USP; flavors; glycerin, USP; magnesium aluminum silicate, NF; polysorbate 40, NF; purified water, USP; sodium benzoate, NF; sucrose, NF; vanillin, NF; and FD& C yellow No. 6.