FIELD: medicine, pharmacy. SUBSTANCE: invention relates to the development of oral compositions consisting of multiple subunits presenting granules with prolonged effect and comprising tramadol or its physiologically tolerant salts and at least one pharmaceutically acceptable compound delaying release of active substance. Invention relates also to method of preparing such compositions. Invention provides preparing tramadol-containing compositions consisting of multiple subunits in simple and especially acceptable form for patients that are deprived of shortcomings typical for the known forms and provides delayed and good reproducible release of active substance. EFFECT: improved method of composition preparing. 15 cl, 14 tbl, 7 dwg, 7 ex
