The Pharmacology of Spinal Opioids and Ziconotide for the Treatment of Non-Cancer Pain.

BACKGROUND: Intrathecal drug delivery has undergone a revitalization following a better understanding of this delivery route and its pharmacokinetics. Driven by patient safety and outcomes, clinicians are motivated to rethink the traditional spinal infusion pump patient selection criteria and indications. We review the current understanding of the pharmacology of commonly employed intrathecal agents and the clinical relevance. METHODS: Search strategies for data acquisition included Medline database, PubMed, Google scholar, along with international and national professional meeting content, with key words including pharmacology of opioids, intrathecal therapy, ziconotide, pharmacokinetics, and intrathecal drug delivery. The search results were limited to the English language. RESULTS: Over 300 papers were identified. The literature was condensed and digested to evaluate the most commonly used medications in practice, sto serve as a foundation for review. We review on-label medications: ziconotide and morphine, and off label medications including fentanyl, sufentail, and hydromorphine. CONCLUSION: Intrathecal therapy has level-one evidence for use for malignant pain and nonmalignant pain, with continued cost savings and improved safety. To most effectively serve our patients, a clear appreciation for the pharmacology of these commonly employed medication is paramount.

Current and future trends in spinal cord stimulation for chronic pain.

Spinal cord stimulation (SCS) is a reversible treatment for chronic pain that is gaining favor as a first-line therapy for many disease states. Because there are no addictive issues and no side effects systemically, the treatment is moving up the treatment continuum ladder. First used clinically in 1967, the procedure was used exclusively for failed back surgery syndrome. Over the past 30 years selection criteria, psychologic screening, and technology have improved. These advances have broadened the treatment options for many patients in pain. This review focuses on the selection, indications, techniques, new advances, complications, and outcomes involved with SCS. A review is provided for the treatment of radiculitis, failed back surgery syndrome, complex regional pain syndrome, peripheral neuropathies, pelvic pain, occipital neuralgia, angina, ischemic extremity pain, and spasticity. Technologic advances such as multi-lead and multi-electrode arrays are also discussed in regard to the impact these developments have on the clinical application of the therapy.

Stability, compatibility, and safety of intrathecal bupivacaine administered chronically via an implantable delivery system.

OBJECTIVE: The only agent approved by the U.S. Food and Drug Administration for chronic intrathecal infusion for the treatment of chronic pain is morphine sulfate. In patients who do not experience adequate relief from intrathecal opioids, bupivacaine is frequently added to increase efficacy. The studies reported here were conducted to demonstrate the stability and compatibility of bupivacaine in a commonly used implantable infusion system and the long-term clinical safety of this therapy. METHODS: A commercially available bupivacaine solution (7.5 mg/ml) was incubated at 37 degrees C for 12 weeks with intact delivery systems and with the individual materials that comprise the fluid pathway. Intermittent samples were collected and analyzed using liquid chromatography. Materials chronically exposed to bupivacaine were analyzed for mechanical integrity. One hundred eight patients treated with intrathecal bupivacaine (average dose: 10 mg/d, range: 2-25 mg/d) and opioids for an average duration of 86 weeks were monitored clinically (patient interviews and neurologic examinations) approximately every 4 weeks. RESULTS: Bupivacaine concentrations remained greater than 96% of the starting material after chronic exposure to the delivery system materials or the intact pump-catheter systems. and the mechanical integrity of the delivery system and materials remained intact. When combined with intrathecal morphine or hydromorphone, no clinical evidence of drug-induced toxicity or complications was observed in any patient. Supplementing opioid therapy with bupivacaine allowed the pain patient to continue to be effectively managed using an implantable intrathecal delivery system. CONCLUSIONS: Bupivacaine is stable and compatible with a commonly used implantable drug infusion system. In this study, chronic supplementation of intrathecal opioids with bupivacaine was a safe method for providing continued management of chronic pain of cancer or noncancer origin.

Coronary artery muscle bridging causing class III angina in a patient with no coronary atherosclerosis.

The significance of coronary artery muscle bridging (MB) has been debated since its first angiographic description by Portsmann and colleagues in 1960 (1). The course is usually benign; however, angina, myocardial infarction, sudden death, arrhythmias, and complete heart block have been reported. In this article, we present a case of coronary artery muscle bridging which caused a patient with no angiographic evidence of atherosclerosis to experience Class III angina.