Complications of intrathecal polypharmacy, medication side effects, and overdose

Abstract

IDDS can offer pain relief for a broad range of chronic pain states including neuropathies, complex regional pain syndrome, rheumatoid arthritis, connective tissue disorders, chronic pancreatitis, and other visceral pain diseases. These devices can dramatically improve the quality of life for patients who have failed oral or transdermal medications (either due to poor analgesia or intolerable side effects) and/or spinal cord stimulation. The FDA originally approved infusions of morphine and baclofen in IDDS. However, morphine alone failed to provide adequate analgesia in many patients. Clinician began to add adjuncts to the infusions to improve pain control. With time, more data became available to assess the effectiveness and safety of adjunct medications. An expert panel convened to review these practices and developed an algorithm for IDDS medication management. Since the 1990s, several medications have been infused through the IDDS including bupivacaine, ziconotide, clonidine, midazolam, ketamine, tetracaine, hydromorphone, fentanyl, sufentanil, gabapentin, and other drugs. Animal toxicity data and human safety information have been studied for many of these agents. IDDS have improved the quality of life for a variety of patients. In 2006, a cluster of patients were noted to suffer respiratory arrest and death 1 day after implantation of IDDS. This prompted a review of the literature to define the mortality associated with IDDS. The investigators identified several physician practices that increased patients’ risk of mortality in the perioperative period. An expert panel convened and developed guidelines to improve the safety of IDDS.