An implantable, gas pressure-operated infusion pump includes a throttle portion, a controllable valve upstream or downstream of the throttle portion, and a controller that controls the opening duration and/or opening frequency of the valve. A method for operating the infusion pump includes determining a standard volume of a standard infusate dispensed by the infusion pump within a pre-determined time period and determining an infusate volume of an infusate, having a different composition than the standard infusate, dispensed by the infusion pump within the pre-determined time period. The method further includes operating the infusion pump together with the infusate at an opening duration and/or opening frequency of the valve that is reduced or increased compared with operating the infusion pump together with the standard infusate in order to dispense a volume of infusate substantially the same as the standard volume.
