The invention relates to a pharmaceutical formulation which is characterised by delayed release of the active ingredient. Said formulation contains 3-(3-dimethylamino-1-ethyl-2-methyl-propyl)phenol or one of its pharmaceutically acceptable salts in a matrix with delayed release of the active ingredient. Said matrix contains between 1 and 80 wt.% of at least one hydrophilic or hydrophobic polymer as a pharmaceutically acceptable matrix forming agent and exhibits, in vitro, the following dissolution speed: between 3 and 35 wt.% (in relation to 100 wt.% of active ingredient) of 3-(3-dimethylamino-1-ethyl-2-methyl-propyl)phenol is released after half an hour, between 5 and 50 wt.% of 3-(3-dimethylamino-1-ethyl-2-methyl-propyl)phenol is released after one hour, between 10 and 75 wt.% of 3-(3-dimethylamino-1-ethyl- 2- methyl-propyl)phenol is released after two hours, between 15 and 82 wt.% of 3-(3-dimethylamino-1-ethyl-2-methyl-propyl)phenol is released after three hours, between 30 and 97 wt.% of 3-(3-dimethylamino-1-ethyl-2-methyl-propyl)phenol is released after six hours, more than 50 wt.% of 3-(3-dimethylamino-1-ethyl-2- methyl- propyl)phenol is released after twelve hours, more than 70 wt.% of 3-(3- dimethylamino- 1-ethyl-2-methyl-propyl)phenol is released after eighteen hours, and more than 80 wt.% of 3-(3-dimethylamino-1-ethyl-2-methyl-propyl)phenol is released after twenty- four hours. The slow release of the active ingredient is achieved by means of a slow release matrix, by means of a normal matrix with a coating which retards the release of the active ingredient or by means of an osmotically driven release system.
