FDA has warned healthcare providers about the risks of using unapproved medicines in pain pumps, such as Medtronic's SynchroMed and Johnson & Johnson's Codman 3000.
Physicians use compounded drugs and off-label medicines including fentanyl in the devices to better manage the pain experienced by their patients.
However, FDA is advising physicians to stick to the approved medicines as off-label drugs raise the risk of pump failure and dosing errors.
The use of off-label medications in implanted pain pumps is a contentious topic. In 2012, Medtronic sent an urgent medical device safety notification warning that "the use of unapproved drugs can lead to intermittent or permanent pump motor stalls" and could result in serious injury or death.
Medtronic's warning sparked a collective response from the heads of U.S. and international societies of pain physicians and neuromodulation experts. Writing in the journal Pain Physician in 2013, the leaders said "the vast majority of patients receiving continuous long term intrathecal therapy for pain are receiving compounded admixtures of medications." The leaders argued these compounded products were needed given "the lack of commercially available preparations" with comparable effects.
Following that exchange, there is strong evidence that physicians have continued to use off-label drugs in pain pumps. In 2016, recommendations from the Polyanalgesic Consensus Conference stated that "most clinicians utilize compounded off-label medications and admixtures." The experts added that "the incident rate of motor stalls for approved and non-approved medications is similar."
FDA is more concerned about the practice.
"While medical devices, such as implanted pumps that deliver medication directly into the spinal fluid, have the potential to play an important role in treating pain, their use must be judicious and their instructions for use must be carefully followed. This is especially true when it comes to implantable pumps that deliver analgesic medicine directly into the nervous system," FDA Commissioner Scott Gottlieb said in a statement.
Gottlieb made the statement after FDA analyzed medical device reports describing adverse events and reviewed data from other sources. The analysis led FDA to conclude off-label use is happening and poses multiple risks.
Pump failure is one concern. The physicians who responded to Medtronic argued pumps can fail with approved and off-label drugs and, as such, careful monitoring is a better approach than prohibition. However, data reviewed by FDA suggests the risk of pump failure more than doubles when devices are filled with unapproved drugs.
FDA thinks some of the failures associated with off-label drugs may occur because of the presence of preservatives or other elements that damage pump tubing or corrode the pumping mechanism. The pumps were not designed to prevent the potential damage caused by these preservatives.
The other main problem discussed by FDA relates to dosing errors. Pumps come with software for calculating the right dose of approved drugs. The software is calibrated to these particular drugs. FDA is concerned that using other drugs, or combinations of medicines, could lead to dosing errors.
In light of these risks, FDA wants physicians to review the labels of implanted pumps and be aware that using off-label medicines may create additional risks for patients.