Abstract: An infusion pump can be configured to modulate a drive motor based on perceived infusion pressure requirements for quieter, more energy-efficient operation of the drive motor. The infusion pump can include an electrical motor having a variable output torque based on the electrical current input, a plunger head sensor configured to detect a force between a plunger driver and a plunger of a medicament container, and a control module configured to regulate the electrical current input to the electrical motor based on the detected force between the plunger driver and the plunger medicament container. The electrical current input for such an infusion pump can be incrementally reduced according to defined magnitudes of detected force.