/truy meth"euh prim/ , n. Pharm.
a synthetic crystalline compound, C 11 H 18 N 4 O 3 , usually combined with a sulfonamide as an antibiotic preparation in the treatment of urinary tract infections and pneumocystis pneumonia.
[ 1960-65; trimetho ( xyphenyl ) + p ( y ) rim ( idinediamine ), components of its chemical name ]