An implantable drug pump that Medtronic Inc. recalled has a potentially life-threatening design problem, says the U.S. Food and Drug Administration.

When a film formed on the battery, the pump was observed to malfunction and failed to deliver the drug to the patient to treat pain, spasms and other conditions. This is a potentially life-threatening design flaw.

The SynchroMed II delivers drugs directly into the spinal fluid to treat chronic pain and spasticity.

Medtronic recalled the product in July, notifying the FDA, patients and doctors about the issue.

The FDA classified the recall as class one, a defective device that can potentially cause harm.

The recall affects SynchroMed II implantable pump models 8637-20 and 8637-40, distributed from 2004 through this July.

The Medtronic SynchroMed II programmable infusion system for intrathecal drug delivery includes an implanted pump that can be programmed noninvasively. Once implanted, the SynchroMed pump stores and delivers medication according to instructions programmed by the physician.

An infusion pump infuses fluids, medication or nutrients into a patient's circulatory system. It is generally used intravenously, although subcutaneous, arterial and epidural infusions are occasionally used. Drugs such as morphine sulfate, ziconotide and baclofen, which are used for the treatment of chronic pain, severe chronic pain and severe spasticity, respectively, are administered by infusion pump.