An implantable programmable medication infusion system comprises an implantable portion (2) having a medication reservoir (10) at below body pressure and isolated at its input from the body in which it is implanted by an antechamber (8) the pressure integrity of which is checked before filling the medication reservoir (10). Safety features include a leak detector (35), inlet and outlet valves (14 and 212) used with flow impeding filters (12 and 218), and a maximum allowable pressure in a pulsatile bellows pump (202) all of which prevent undesired infusion of medication. Medication flow from the pulsatile bellows pump (202) is in response to programming commands from a drug programming system (1) and processed in an electronics section (30) which uses the commands to program memory units (320 and 322) and to request pulses of medication. Hardwired limit controls (324 and 326) prevent excessive dosage requests from reaching the pulsatile bellows pump (202). For patient convenience and safety, the memory units (320 and 322) are programmed with running integral limits. A record of medication dispensing can be communicated to a physician by means of a telemetry transmitter (336) which sends signals by telemetry to the communications head (300) which information is displayed on the drug programming unit (3).