Arrangement (100, 200, 300) for administering a predetermined amount of a substance into an organism having a tissue, the arrangement comprising: a pump adapted to be coupled to a reservoir holding fluid containing the substance and adapted to drive the substance containing fluid via a tubing; a member (129, 229, 329) comprising a pressure sensor and being adapted to, based on at least two pressure measurements in the tubing by the sensor, provide information indicative of a tissue resistance, being a resistance of the tissue against flow of the fluid containing the substance upon administration into the tissue; a controller (131, 231, 331) adapted to control the pump to adjust an administration characteristic of the fluid based on the information such as to achieve an intended absorption rate of the substance, the absorption rate of the substance representing a speed or an extent at which the substance is absorbed from an administration site into a blood stream of the organism, wherein the information indicative of the tissue resistance comprises a value of the tissue resistance, wherein the arrangement is adapted to previously determine a relationship between the absorption rate of the substance and possible tissue resistance, and to determine a tissue resistance threshold for the injection site, wherein the controller (131, 231, 331) is adapted to control the pump based on the administration characteristic comprising at least one definition of an exogenous factor comprising a duration of use of the administration site for administering the fluid into the organism, wherein the intended absorption rate of the substance is a desired or a predetermined absorption rate of the substance to which an actual absorption rate of the substance should come close or be identical to, wherein the arrangement is adapted to indicate to a user that a maximum duration of use of the administration site is reached and that the administration site should be changed, if the tissue resistance exceeds the tissue resistance threshold. a pump adapted to be coupled to a reservoir holding fluid containing the substance and adapted to drive the substance containing fluid via a tubing; a member (129, 229, 329) comprising a pressure sensor and being adapted to, based on at least two pressure measurements in the tubing by the sensor, provide information indicative of a tissue resistance, being a resistance of the tissue against flow of the fluid containing the substance upon administration into the tissue; a controller (131, 231, 331) adapted to control the pump to adjust an administration characteristic of the fluid based on the information such as to achieve an intended absorption rate of the substance, the absorption rate of the substance representing a speed or an extent at which the substance is absorbed from an administration site into a blood stream of the organism, wherein the information indicative of the tissue resistance comprises a value of the tissue resistance, wherein the arrangement is adapted to previously determine a relationship between the absorption rate of the substance and possible tissue resistance, and to determine a tissue resistance threshold for the injection site, wherein the controller (131, 231, 331) is adapted to control the pump based on the administration characteristic comprising at least one definition of an exogenous factor comprising a duration of use of the administration site for administering the fluid into the organism, wherein the intended absorption rate of the substance is a desired or a predetermined absorption rate of the substance to which an actual absorption rate of the substance should come close or be identical to, wherein the arrangement is adapted to indicate to a user that a maximum duration of use of the administration site is reached and that the administration site should be changed, if the tissue resistance exceeds the tissue resistance threshold.