A transdermal therapeutic system for use in the relief of pain by administering an active ingredient through the skin during an intended time of wearing of from 3 to 7 days consisting of a) a back layer, b) a pressure-sensitive matrix layer containing the active ingredient, and c) a release-liner, as well as optionally b1) an additional adhesive layer or an overtape which improve the adhesion of the transdermal therapeutic system to the skin and which are applied to the pressure-sensitive matrix layer, or b2) a membrane which controls the release of the active ingredient and on which an adhesive layer is located wherein the membrane is applied to the pressure-sensitive matrix layer, wherein the active ingredient is fentanyl or an analogue of the fentanyl selected from alfentanil, carfentanil, lofentanil, remifentanil, and trefentanil or a salt of one of said active ingredients and wherein the matrix layer is free from gel-forming agents and contains a mixture of a polyisobutylene A and a polyisobutylene B as a pressure-sensitive polymer, wherein the content of the polyisobutylene A to the polyisobutylene B in the matrix layer is in the range of from 20%: 80% to 40%: 60% each based on the total weight of the polyisobutylenes A and B, and wherein the polyisobutylene A has a storage modulus G' the value of which is substantially constant the temperature range of from 10°C to 40°C, and the polyisobutylene B has a storage modulus G' the value of which continuously decreases with an increasing temperature in the temperature range of from 10°C to 40°C, wherein the storage modulus G' is measured in the linear viscoelastic range at a frequency of 10 rad/sec using a rheometer with a parallel plate geometry and parallel plates, and wherein the pressure-sensitive matrix layer contains undissolved active ingredient in the form of active ingredient particles and after application to the skin for the duration of the intended time of wearing has a residual active ingredient content of less than 35%, preferably less than 25% of the initial content of active ingredient. a) a back layer, b) a pressure-sensitive matrix layer containing the active ingredient, and c) a release-liner, as well as optionally b1) an additional adhesive layer or an overtape which improve the adhesion of the transdermal therapeutic system to the skin and which are applied to the pressure-sensitive matrix layer, or b2) a membrane which controls the release of the active ingredient and on which an adhesive layer is located wherein the membrane is applied to the pressure-sensitive matrix layer, b1) an additional adhesive layer or an overtape which improve the adhesion of the transdermal therapeutic system to the skin and which are applied to the pressure-sensitive matrix layer, or b2) a membrane which controls the release of the active ingredient and on which an adhesive layer is located wherein the membrane is applied to the pressure-sensitive matrix layer, wherein the active ingredient is fentanyl or an analogue of the fentanyl selected from alfentanil, carfentanil, lofentanil, remifentanil, and trefentanil or a salt of one of said active ingredients and wherein the matrix layer is free from gel-forming agents and contains a mixture of a polyisobutylene A and a polyisobutylene B as a pressure-sensitive polymer, wherein the content of the polyisobutylene A to the polyisobutylene B in the matrix layer is in the range of from 20%: 80% to 40%: 60% each based on the total weight of the polyisobutylenes A and B, and wherein the polyisobutylene A has a storage modulus G' the value of which is substantially constant the temperature range of from 10°C to 40°C, and the polyisobutylene B has a storage modulus G' the value of which continuously decreases with an increasing temperature in the temperature range of from 10°C to 40°C, wherein the storage modulus G' is measured in the linear viscoelastic range at a frequency of 10 rad/sec using a rheometer with a parallel plate geometry and parallel plates, and wherein the pressure-sensitive matrix layer contains undissolved active ingredient in the form of active ingredient particles and after application to the skin for the duration of the intended time of wearing has a residual active ingredient content of less than 35%, preferably less than 25% of the initial content of active ingredient.