Medical device maker Medtronic PLC said two people have died following dosing errors with its problem-plagued SynchroMed II infusion pump, an implanted device made in Minnesota that slowly injects pain medications into a patient's spinal canal.
More than 238,000 of the devices have been implanted in patients with advanced metastatic cancer, chronic pain and severe spasticity. Various problems with the device have been linked to more than a dozen deaths in recent years. The Food and Drug Administration filed a consent decree against Medtronic in 2015 for repeated failures to correct manufacturing problems.
On Tuesday, regulators in the United Kingdom published an update from Medtronic on the specific problem of "overinfusion," which happens when the programmable SynchroMed II puts out more pain medication than intended.
The issue of overinfusion was first disclosed in March 2014. A three-page update published online Tuesday by the U.K.'s Medicines and Healthcare Products Regulatory Agency said an ongoing analysis by Medtronic has concluded two patients have died and 103 pumps were affected by issues that led to overinfusion of pain drugs through July 5, 2016.
"Medtronic has been unable to establish a definitive causal relationship between the adverse events and overinfusion, due to potential contributing factors. However, it is reasonable to conclude that overinfusion was a contributing factor," Medtronic's letter to doctors on the overinfusion issue said.
The other contributing factors include the dosage of the infused drug, patient medical history, and simultaneous use of other drugs including oral opioids, the letter said. Of the 103 pumps linked to adverse events, 99 of the devices were filled with "non-indicated" drug formulations the last time the pumps' reservoirs were refilled.
Medtronic recommends using only approved drugs and concentrations in the pumps, and to examine patients for signs of overdose or withdrawal during refill appointments. Withdrawal from medication is a potential issue because overinfusion can potentially deplete the pump's reservoir without setting off the device alarm, causing the drug to stop flowing unexpectedly.
The company does not recommend removing the device without first seeing signs of problems.
