Dr. David Caraway was another intriguing presenter at the 2013 NANS meeting. His discussion, On-label and Off-label Use of Intrathecal Medications and PACC Review, hit some very controversial issues over which many of my clients have expressed concerns. He started by reviewing the history of the PACC guidelines development process, going back to the year 2000 when the initial considerations were based on literature, and he then moved on to subsequent committees that have been gathering the clinical data that has been used to produce the guidelines over the last decade.
Dr. Caraway expressed, as has Hartley Medical in the past, that the PACC guidelines are just that: guidelines. He expressed that physicians should not feel limited by the guidelines in the treatment of their patients, as some treatment regimens may deviate from guideline recommendations. He then transitioned to the Medtronic warning letter, issued in 2012, relating to the utilization of off-label drugs within the pump. The letter emphasized adverse events associated with off-label drug use administered through the Synchromed II pump, including corrosion and failure. Dr. Caraway reviewed a study of pump failures related to motor stalls within the Synchromed II pump. This study specifically looked at the rate of motor stall over time comparing FDA approved and off-label drugs administered through the pump.
This analysis, according to the ISPR database, showed the rate of pump failure in pumps utilizing approved drugs, and failing at 78 months post implantation, to be 2.4% versus 7.0% for off-label use drugs.
Dr. Caraway highlighted this critical point: the adverse event is pump failure. He then highlighted the clinical consequences of pump failure, placing heavy focus on therapy interruption (there is no data suggesting an increase in mortality). Dr. Caraway noted that failures associated with off-label drug use, however, are far less common than catheter failure rates and that catheter failures have the same consequences as motor stalls.
He concluded his presentation regarding the use of off-label medication administered through implantable pumps with the following key points: motor stalls may cause an interruption of treatment, and off-label medication use may result in a decrease in pump life. Clinicians need to make wise choices in the use of certain medications that are clinically required and supported by guidelines for the treatment of chronic pain. They must become acutely aware of potential catheter failures, educate their patients regarding the signs and symptoms of therapy withdrawal, and be respectful of current guidelines for monitoring, drug selection and mixtures. This was once again a remarkable presentation given by Dr. Caraway, and I highly encourage individuals to read his work and attend his future lectures.