Intrathecal therapy for the management of cancer pain

Abstract

Inadequately managed cancer pain continues to be a significant problem despite increased awareness, improved knowledge and understanding of pain pathophysiology, and standardized treatment guidelines of this distressing and debilitating symptom complex. Small subsets of patients who are refractory to optimal medical management because of drug toxicity or unsatisfactory analgesia may be candidates for exteriorized or implantable intrathecal drug delivery systems. By delivering opioids and other agents directly to the central nervous system, intrathecal drug administration can offer superior pain relief with less toxicity at a fraction of the systemic dose. With adjuncts such as local anesthetics and clonidine, intrathecal therapy also allows for broader therapeutic options in the most difficult of cases. In general, intrathecal therapy is underused despite evidence of its efficacy, safety, and cost-effectiveness.

Prospective Observational Study of Patient-Controlled Intrathecal Analgesia

“…9 Since the 1980s, implantable and programmable intrathecal pumps have become an accepted and safe modality for treating chronic pain, particularly in cancer pain. 10 For patients receiving intrathecal analgesia, practice guidelines have been published to assist with appropriate drug selection and dosing. 11 A deficiency of ITT has been difficulty in rapidly titrating the intrathecal medications to cover breakthrough pain (BTP), necessitating that patients use oral or transmucosal breakthrough medications in addition to the basal pain control obtained by their pumps.…”

Measured Density and Calculated Baricity of Custom-Compounded Drugs for Chronic Intrathecal Infusion

“…22,25,26 Morphine sulfate, clonidine hydrochloride, bupivacaine hydrochloride, and baclofen hydrochloride salts, all purchased from a single supplier (Sigma-Aldrich Inc, St Louis, Mo), were weighed on a balance (model AB104; Mettler-Toledo, Columbus, Ohio) to the nearest 0.0001 g. The mass of drug for the most concentrated solution of each drug (morphine 50 mg/mL, bupivacaine 20 mg/mL, clonidine 3 mg/mL, and baclofen 4 mg/mL) was added to a Pyrex class A volumetric flask (Corning Inc, Corning, New York) and filled to volume with 0.9% normal saline (Baxter, Deerfield, Ill). Hydrochloric acid (0.1 normal) in volumes between 10 and 100 KL was added as necessary to facilitate dissolution.…”

“…22,23 In addition, we determined an equation for the Bbest-fit[ curve through the data points so that clinicians can calculate the density of each study drug at other concentrations. Finally, we used literature values for the density of CSF 24 to calculate the baricity of the solutions studied here.…”

Intrathecal Pumps

“…9,10 Initially focused on failed back syndrome, indications have now expanded to include complex regional pain syndrome, postherpetic neuralgia and painful peripheral neuropathy. 11 The rapid advent of IT analgesic delivery required the technology to support continuous infusion to provide prolonged, constant levels and to maximize therapeutic effects while limiting side effects.…”