Polyanalgesic Consensus Conference 2003: an update on the management of pain by intraspinal drug delivery-- report of an expert panel.

Intraspinal drug infusion using fully implantable pump and catheter systems is a safe and effective therapy for selected patients with chronic pain. The options for this approach are increasing, as drugs that are commercially available for systemic administration are adapted to this use and other drugs that are in development specifically for intraspinal administration become available. In 2000 a Polyanalgesic Consensus Conference was organized to evaluate the existing literature and develop guidelines for drug selection. The major outcome of this effort, an algorithm for drug selection, was based on the best available evidence at the time. Rapid changes have occurred in the science and practice of intraspinal infusion and a Polyanalgesic Consensus Conference 2003 was organized to pursue the following goals: 1) to review the literature on intraspinal drug infusion since 1999, 2) to revise the 2000 drug-selection algorithm, 3) to develop guidelines for optimizing drug dosage and concentration, 4) to create a process for documenting minimum evidence supporting the use of a drug for intraspinal infusion, and 5) to clarify issues pertaining to compounding of drugs. Based on the best available evidence and expert opinion, consensus recommendations were developed in all these areas. The panel's conclusions may provide a foundation for clinical practice and a rational basis for new research.

The dilemma of conversion from systemic to epidural morphine: a proposed conversion tool for treatment of cancer pain.

There is lack of concensus over what constitutes an appropriate method to affect an equianalgesic conversion from systemic to epidural morphine. A systematic approach to calculate the appropriate starting dose for epidural morphine is needed. A model is proposed here and data from a pilot study are described supporting the concept as well as its utility in the clinical setting. Several key factors may have an impact upon the selection of a starting dose in the opioid-tolerant cancer population such as pain severity, age, previous systemic opioid use, and presence of neuropathic pain. A conversion tool was developed taking these 4 factors into account and was tested in a small number of patients with cancer pain. The rationale for this approach is explored. Four case examples are presented to demonstrate the utilization of the tool and the effectiveness of this formula for clinical practice. Further study is needed to firmly establish the validity and reliability of this tool.

Chronic epidural bupivacaine-opioid infusion in intractable cancer pain.

This study examined the efficacy and toxicity associated with chronic epidural opioid-bupivacaine infusions. In a series of 68 patients with cancer pain refractory to epidural opioids alone, analgesia was effectively regained by infusing a opioid-bupivacaine combination. Sixty-one patients (90%) were considered treatment successes, according to conventional criteria. Median length of therapy was 60-120 days, with the longest infusion lasting 277 days. Chronic bupivacaine infusion concentrations ranged from 0.1 to 0.5% with infusion rates varying from 4 to 18 ml/h. The majority of patients experienced pain relief with little or no sympathetic or sensorimotor impairment after the first 24 h at bupivacaine concentrations of 0.125-0.25% and were managed in home or chronic care settings without the need for re-hospitalization. In patients receiving higher bupivacaine concentrations, sympathetic, sensory and motor blockade were well tolerated during chronic infusion. Sensory loss was consistently observed only at bupivacaine concentrations exceeding 0.25%, and motor impairment occurred only at concentrations exceeding 0.35%. Postural hypotension was observed in 6 patients (9%) for the first 24 h only, which supports the requirement for monitoring and fluid therapy during initiation of the bupivacaine infusion. No patient experienced CNS or systemic toxicity, despite plasma total bupivacaine concentrations as high as 10.8 micrograms/ml. Serial plasma bupivacaine levels were measured in 15 patients during chronic infusion. There was considerable inter- and intra-individual variability in plasma bupivacaine concentrations and bupivacaine clearance. We conclude that epidural opioid-bupivacaine infusion is an effective and safe technique for long-term administration of analgesics in the refractory cancer patient.