Intrathecal Hydromorphone for Chronic Nonmalignant Pain: A Retrospective Study

The Polyanalgesic Consensus Conference (PACC)®: Intrathecal Drug Delivery Guidance on Safety and Therapy Optimization When Treating Chronic Noncancer Pain

INTRODUCTION

The International Neuromodulation Society convened a multispecialty group of physicians and scientists based on expertise with international representation to establish evidence-based guidance on intrathecal drug delivery in treating chronic pain. This Polyanalgesic Consensus Conference (PACC)® project, created more than two decades ago, intends to provide evidence-based guidance for important safety and efficacy issues surrounding intrathecal drug delivery and its impact on the practice of neuromodulation.

MATERIALS AND METHODS

Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when PACC® last published guidelines) to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence is scant.

RESULTS

The PACC® examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process.

CONCLUSIONS

The PACC® recommends best practices regarding intrathecal drug delivery to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

The Options for Neuraxial Drug Administration

Neuraxial drug administration, i.e., the injection of drugs into the epidural or intrathecal space to produce anesthesia or analgesia, is a technique developed more than 120 years ago. Today, it still is widely used in daily practice in anesthesiology and in acute and chronic pain therapy. A multitude of different drugs have been introduced for neuraxial injection, only a part of which have obtained official approval for that indication. A broad understanding of the pharmacology of those agents is essential to the clinician to utilize them in a safe and efficient manner. In the present narrative review, we summarize current knowledge on neuraxial anatomy relevant to clinical practice, including pediatric anatomy. Then, we delineate the general pharmacology of neuraxial drug administration, with particular attention to specific aspects of epidural and intrathecal pharmacokinetics and pharmacodynamics. Furthermore, we describe the most common clinical indications for neuraxial drug administration, including the perioperative setting, obstetrics, and chronic pain. Then, we discuss possible neurotoxic effects of neuraxial drugs, and moreover, we detail the specific properties of the most commonly used neuraxial drugs that are relevant to clinicians who employ epidural or intrathecal drug administration, in order to ensure adequate treatment and patient safety in these techniques. Finally, we give a brief overview on new developments in neuraxial drug therapy.

Intrathecal hydromorphone as an analgesia option for gynecology patients

Enhanced recovery after surgery (ERAS) is a multimodal perioperative strategy originally developed to attenuate the postsurgical stress response in patients after colorectal surgery. Patients undergoing gynecologic surgery who had ERAS had significantly shorter hospital length of stay, reduced hospital-related costs, and acceptable pain management with reduced opioid use, without compromising patient satisfaction. Intrathecal hydromorphone is an effective alternative ERAS protocol analgesia for these patients and will not compromise patient outcomes or healthcare costs.

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..

Determination of ED50 of hydromorphone for postoperative analgesia following cesarean delivery

BACKGROUND

Morphine is the most common opioid injected into the intrathecal space for postoperative analgesia following cesarean delivery, but ongoing medication shortages have resulted in limited availability. One proposed morphine alternative is hydromorphone. Studies investigating its use in post-cesarean analgesia are limited. This study was conducted to determine the median effective dose of intrathecal hydromorphone 12h postpartum.

METHODS

Twenty healthy women undergoing elective cesarean delivery were recruited into this study. Hydromorphone doses were determined using the up-down sequential method. The study dose of hydromorphone started at 6μg and was raised or lowered by 2μg depending on the 12-h efficacy of the preceding participant's dose. Pain scores of <3/10 were considered successful and the subsequent patient received a lower dose. Participants received 0.5% bupivacaine 12.5mg, fentanyl 25μg, and the study dose of hydromorphone as a single intrathecal injection.

RESULTS

Ten of 20 participants reported an effective hydromorphone dosage 12h post-injection. The median effective hydromorphone dosage was 4.6μg (95% CI 3.72 to 5.48μg) based on participants' reported visual analog pain scores of <3/10. No significant side effects or adverse outcomes were observed.

CONCLUSION

Intrathecal hydromorphone may be an effective alternative to morphine for post-cesarean pain management. The amount of intrathecal hydromorphone necessary to provide analgesia at 12h postoperatively may be significantly lower than doses currently in use. Further research should be performed to identify the optimal dose of intrathecal hydromorphone for post-surgical pain relief.

Novel polymeric bioerodable microparticles for prolonged-release intrathecal delivery of analgesic agents for relief of intractable cancer-related pain

Intractable cancer-related pain complicated by a neuropathic component due to nerve impingement is poorly alleviated even by escalating doses of a strong opioid analgesic. To address this unmet medical need, we developed sustained-release, bioerodable, hydromorphone (potent strong opioid)- and ketamine (analgesic adjuvant)-loaded microparticles for intrathecal (i.t.) coadministration. Drug-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles were prepared using a water-in-oil-in-water method with evaporation. Encapsulation efficiency of hydromorphone and ketamine in PLGA (50:50) microparticles was 26% and 56%, respectively. Microparticles had the desired size range (20-60 μm) and in vitro release was prolonged at ≥28 days. Microparticles were stable for ≥6 months when stored refrigerated protected from light in a desiccator. Desirably, i.t. injected fluorescent dye-labeled PLGA microparticles in rats remained in the lumbar region for ≥7 days. In a rat model of neuropathic pain, i.t. coinjection of hydromorphone- and ketamine-loaded microparticles (each 1 mg) produced analgesia for 8 h only. Possible explanations include inadequate release of ketamine and/or hydromorphone into the spinal fluid, and/or insufficient ketamine loading to prevent development of analgesic tolerance to the released hydromorphone. As sub-analgesic doses of i.t. ketamine at 24-48 h intervals restored analgesia on each occasion, insufficient ketamine loading appears problematic. We will investigate these issues in future work.

The Relationship Between the Mechanisms of Action and Safety Profiles of Intrathecal Morphine and Ziconotide: A Review of the Literature

OBJECTIVE

To better characterize safety profiles associated with the intrathecal (IT) administration of morphine and ziconotide and discuss how they relate to mechanisms of action.

METHODS

Published data were evaluated to identify potential relationships between safety profiles of IT morphine and IT ziconotide and their mechanisms of action.

RESULTS

Potentially severe and clinically relevant adverse events (AEs) associated with IT morphine include respiratory depression, tolerance, and granuloma formulation, whereas IT ziconotide is associated with neuropsychiatric AEs, such as cognitive impairment, hallucinations, and changes in mood or consciousness, particularly with high doses and rapid titration. AEs associated with these IT therapies may result from spread of the medication out of the IT space into areas of the central and peripheral nervous systems and systemic circulation. AEs that occur usually can be managed and, in some cases, prevented. To mitigate risk, patients' histories should be reviewed to identify potential complicating factors (e.g., obesity or other risk factors for respiratory dysfunction in patients receiving IT morphine; a history of psychosis in patients receiving IT ziconotide). Also, treatment should be initiated at a low dose, titrated slowly, and patients should be closely monitored during treatment.

CONCLUSIONS

IT morphine and IT ziconotide are approved by the US Food and Drug Administration for patients who do not respond to less invasive treatments, but the safety profiles of each may make them more or less appropriate for certain patient populations.

Intrathecal drug administration in chronic pain syndromes

Chronic pain may recur after initial response to strong opioids in both patients with cancer and patients without cancer or therapy may be complicated by intolerable side effects. When minimally invasive interventional pain management techniques also fail to provide satisfactory pain relief, continuous intrathecal analgesic administration may be considered. Only 3 products have been officially approved for long-term intrathecal administration: morphine, baclofen, and ziconotide. The efficacy of intrathecal ziconotide for the management of patients with severe chronic refractory noncancer pain was illustrated in 3 placebo-controlled trials. A randomized study showed this treatment option to be effective over a short follow-up period for patients with pain due to cancer or AIDS. The efficacy of intrathecal opioid administration for the management of chronic noncancer pain is mainly derived from prospective and retrospective noncontrolled trials. The effect of intrathecal morphine administration in patients with pain due to cancer was compared with oral or transdermal treatment in a randomized controlled trial, which found better pain control and fewer side effects with intrathecal opioids. Other evidence is derived from cohort studies. Side effects of chronic intrathecal therapy may either be technical (catheter or pump malfunction) or biological (infection). The most troublesome complication is, however, the possibility of granuloma formation at the catheter tip that may induce neurological damage. Given limited studies, the evidence for intrathecal drug administration in patients suffering from cancer-related pain is more compelling than that of chronic noncancer pain.

["Serious" adverse drug reactions with tramadol: a 2010-2011 pharmacovigilance survey in France]

OBJECTIVE

Tramadol is a weak opioid used as a step 2 analgesic, approved in France for moderate to severe pain. After dextropropoxyphene withdrawal, a national pharmacovigilance follow-up of tramadol was decided by the French Drug Agency.

METHODS

All Serious Adverse Drug Reactions (SADR) notified with tramadol to the French PharmacoVigilance Centres (CRPV) and pharmaceutical companies between August 1(st), 2010 and July 31(th), 2011 were analyzed.

RESULTS

During the study period, 296 cases of SADR were notified to CRPV and 59 to pharmaceutical companies. Apart from opiate-related SADR, tramadol induced serotoninergic SADR, including seizures or serotoninergic syndromes. Several « unlabelled » SADR were also identified: some of them, like hyponatremia or hypoglycemia, are poorly known by health professionals. Other were never published: peripheral edema or pancreatitis.

CONCLUSION

This study shows that besides well-known opioid or serotoninergic ADR, tramadol can also induce 2 other relatively unknown ADR: hypoglycemia and hyponatremia.

Persistent hiccups with continuous intrathecal morphine infusion

OBJECTIVE

To report a case of hiccups secondary to intrathecal (IT) morphine infusion.

METHODS

Case report and discussion.

RESULTS

The hiccups in our patient resolved on substitution of IT morphine infusion with hydromorphone.

DISCUSSION

We report a case of a 44-year-old man who developed persistent hiccups with IT morphine infusion pump therapy. The hiccups persisted despite various nonpharmacological and pharmacological measures. The untoward symptom resolved after substitution of IT hydromorphone for IT morphine.

The Role of Interventional Therapies in Cancer Pain Management

Cancer pain is complex and multifactorial. Most cancer pain can be effectively controlled using analgesics in accordance to the WHO analgesic ladder. However, in a small but significant percentage of cancer patients, systemic analgesics fail to provide adequate control of cancer pain. These cancer patients can also suffer from intolerable adverse effects of drug therapy or intractable cancer pain in advance disease. Though the prognosis of these cancer patients is often very limited, the pain relief, reduced medical costs and improvement in function and quality of life from a wide variety of available interventional procedures is extremely invaluable. These interventions can be used as sole agents or as useful adjuncts to supplement analgesics. This review will discuss interventional procedures such as epidural and intrathecal drug infusions, intrathecal neurolysis, sympathetic nervous system blockade, nerve blocks, vertebroplasty and the more invasive neurosurgical procedures. Intrathecal medications including opioids, local anaesthetics, clonidine, and ziconotide will also be discussed. Key words: Intractable pain, Intrathecal analgesia, Neurolysis

Intrathecal narcotic infusion pumps for intractable pain of chronic pancreatitis: a pilot series

OBJECTIVES

The aim of this study was to evaluate the efficacy of intrathecal narcotics pump (ITNP) as an alternative treatment for patients with pain from chronic pancreatitis (CP). ITNP offers the advantages of reversibility, lower total narcotic dose, and the pancreas remaining intact.

METHODS

Thirteen patients (8 female, 5 male), with mean age 40.6 years (s.d. 9.6 years), who had experienced intractable upper abdominal pain from CP were reviewed. Each patient had multiple other failed treatment modalities, including partial pancreatic resection (n = 6). They were offered ITNP after a successful intraspinal opioid trial. Etiologies of CP included idiopathy (n = 3), cystic fibrosis (n = 2), alcohol (n = 2), and pancreas divisum (n = 6).

RESULTS

The median duration of severe, intractable pain prior to ITNP was 6 years (2-22 years). The median follow-up time after ITNP was 29 months (range, 7-94 months). The ITNP was in situ for a mean duration of 29 months (range, 0.5-94 months). Seven patients had pump exchange or removal for various reasons; improvement of pain at month 53 (n = 1), meningitis (n = 1), meningitis with subsequent replacement (n = 1), pump failure at month 31, 68, 79, and 84 (n = 4). There were no deaths. The mean pain score prior to implantation (score = 8.3, s.d. = 0.9) was significantly higher than 1 year after (score = 2.7, s.d. = 1.9) (P < 0.01) and last follow-up (score = 0.75, s.d. = 2.1) (P < 0.01). The median oral narcotic dose before and 1 year after ITNP were morphine sulfate equivalents 337.5 mg per day (range, 67.5-1,320) and 40 mg per day (range, 0-1,680), respectively (P < 0.01). Two patients were considered failures, as they still require a high dosage of both oral and intrathecal medications to control their pain, despite significant pain-score improvement. One patient who was excluded due to meningitis was also considered a failure. Therefore, the overall success rate of ITNP based on an intention-to-treat analysis was 76.9% (10/13). The major complications of ITNP were central nervous system infection requiring pump removal (n = 1), cerebrospinal fluid leak requiring laminectomy (n = 1), and perispinal abscess with bacterial meningitis requiring pump removal (n = 1).

CONCLUSIONS

This study shows the many risks and benefits of ITNP. A longer follow-up is awaited; such pumps appear to be one alternative to aggressive surgical intervention. Failed ITNP trials leave other options open. Therapeutic trials directly comparing pancreatectomy, ITNP, and implanted nerve stimulators are of interest.

Intrathecal drug therapy for long-term pain management

PURPOSE

The use, safety, and efficacy of intrathecal medication administration with implantable pumps for cancer and chronic pain management are reviewed.

SUMMARY

Implanted intrathecal drug-delivery systems (IDDSs) are used for long-term management of persistent, severe pain despite a multimodal approach with conventional pain treatment options. Currently, consensus papers published in the literature are used as guidelines for determining patient selection and medication administration, because there is a lack of supporting evidence from randomized, controlled, clinical trials. Pharmacists have a critical role in the safe use of intrathecal medication. Most of the medication concentrations and combinations administered through IDDSs are not commercially available and therefore must be compounded in a pharmacy. Medications commonly administered through IDDSs include opioids, local anesthetics, clonidine, baclofen, and ziconotide. It is important for pharmacists who prepare products for IDDSs to understand the pharmacology, adverse effects, and concentration limitations of each medication in order to prevent adverse events related to postoperative subarachnoid hemorrhage, infection, catheter-tip inflammatory masses, withdrawal, and overdose. Pharmacists play an important role in maintaining quality assurance of intrathecal drug use, including the use of standard procedures for ordering and compounding medications, documentation of patient education, and monitoring of patient outcomes.

CONCLUSION

The use of long-term intrathecal drug delivery for the treatment of intractable pain or intolerable medication adverse effects has expanded to include the treatment of patients with chronic or cancer-related pain. Important considerations for the use of intrathecal drug therapy include the appropriate selection of patients, delivery systems, and medications, as well as potential complications of therapy and quality-assurance measures necessary to ensure patient safety.

Intrathecal pumps

Direct neuroaxis drug delivery has expanded the physician's armamentarium to provide treatment options to those who have failed more conservative interventions. Starting from Bier's 'cocainization of the spinal cord' in 1898, direct nervous system pharmacy delivery has long been recognized as an effective means to treat pain. Intrathecal pump systems are now commonplace in the management of numerous pain states, as well as of neuromuscular sequelae of central nervous system injury. There has been much advancement in the physiologic and pharmacologic understanding of direct neuromodulation, providing a growing number of treatment options depending on the specific disease state. As well, surgical techniques and catheter systems have undergone refinements providing improved long-term safety and efficacy. We present a review of the historical evolution to current intrathecal therapies, as well as a dialog regarding patient selection, drug options, and side effects. Also, included is a discussion of surgical techniques, current delivery options and complications concerning pump placement.

Intrathecal analgesia

Since the first use of intrathecal (IT) drug infusion systems in the early 1980s, these delivery systems have undergone numerous revisions making them more tolerable, easier to program, and longer lasting. Concurrent with technological advances, the indications for IT pump placement have also been continuously evolving, to the point where the most common indication is now noncancer pain. This article provides an evidence-based review of the indications, efficacy, and complications of IT drug therapy for the most commonly administered spinal analgesics.

Intrathecal analgesia

Since the first use of intrathecal (IT) drug infusion systems in the early 1980s, these delivery systems have undergone numerous revisions making them more tolerable, easier to program, and longer lasting. Concurrent with technological advances, the indications for IT pump placement have also been continuously evolving, to the point where the most common indication is now noncancer pain. This article provides an evidence-based review of the indications, efficacy, and complications of IT drug therapy for the most commonly administered spinal analgesics.

Programmable intrathecal opioid delivery systems for chronic noncancer pain: a systematic review of effectiveness and complications

OBJECTIVES

We conducted a systematic review of the literature on the effectiveness and complications of programmable intrathecal opioid and ziconotide drug delivery systems (IDDS) for patients with chronic noncancer pain.

METHODS

We searched MEDLINE, Cochrane, and other bibliographic databases to identify English-language journal articles reporting programmable IDDS complications or effects on pain or functioning. Additional study methodology criteria were applied for the effectiveness review. Two authors independently abstracted data from each included article.

RESULTS

Six articles met the inclusion criteria for the effectiveness and complications reviews, and 4 others met the criteria only for the complications review; none were randomized trials or of ziconotide. All 6 articles reviewed for effectiveness reported improvement in pain and functioning on average among patients who received a permanent IDDS. Two articles reported the proportion of patients with > or =50% improvement in pain at 6 months (38%, 56%) and 2 at longer follow-ups (30%, 44%). Intrathecal morphine-equivalent doses increased over time. The most commonly reported permanent IDDS drug side effects were nausea/vomiting (mean rate weighted by sample size=33%), urinary retention (24%), and pruritus (26%). Catheter problems were also reported commonly. Rare but serious complications included intrathecal catheter tip granulomas.

CONCLUSIONS

The studies reviewed found improvement in pain and functioning on average among patients with chronic noncancer pain who received permanent IDDS. However, their methodologic limitations preclude conclusions concerning the effectiveness of this technology long-term and as compared with other treatments. Drug side effects and hardware complications were common. Suggestions are made for methodologic improvements in future studies.

Intrathecal Hydromorphone for Intractable Nonmalignant Pain: A Retrospective Study

BACKGROUND

Hydromorphone is often administered intrathecally for the treatment of cancer and nonmalignant chronic intractable pain. It is frequently utilized in combination with other analgesics in a multidrug intrathecal infusion; however, very little data are available documenting efficacy or safety of intrathecal hydromorphone as a solo analgesic.

OBJECTIVE

This study was conducted to examine pain and side effects in patients receiving intrathecal hydromorphone.

DESIGN

A retrospective review was conducted of all patients receiving intrathecal hydromorphone monotherapy in two large pain specialty practices in the Pacific Northwest. All data collected within 30 days of the patient's 3-month, 6-month, and 12-month anniversary of implant were analyzed.

PATIENTS

Twenty-four patients with noncancer-related chronic pain were included in the study. Thirteen patients had eligible pain data at 1 month, 10 patients had pain data at 3 months and seven patients had pain data available at 12 months after initiation of intrathecal hydromorphone.

RESULTS

Average pain scores decreased significantly (P = 0.03). Side-effect and pain-interference scores remained essentially unchanged in this small sample of patients.

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.

Continuous Intrathecal Infusion of Hydromorphone: Safety in the Sheep Model and Clinical Implications

OBJECTIVE

To determine the safety of hydromorphone delivered by continuous intrathecal infusion via implanted delivery systems in sheep.

DESIGN

Sheep implanted with intrathecal infusion systems were randomly assigned to receive either 1.5, 3, or 6 mg/day hydromorphone HCl or saline control (3 sheep/dose level) at a fixed infusion rate of 1.92 mL/day for 28-31 days. Infusions were initiated approximately 5 days after surgical implantation of the delivery systems (pumps and intrathecal catheters), and investigators were blinded to doses administered. An additional group of sheep (N=3) received hydromorphone (open label) at a dose of 12 mg/day. All animals were examined daily during drug infusion for changes in behavior and neurologic function. Cerebrospinal fluid was analyzed for protein, cytology, and hydromorphone concentration in samples collected prior to and at the end of drug infusion. The spinal cord with the catheter in situ was removed en bloc and fixed in formalin for microscopic analysis.

RESULTS

All sheep receiving intrathecal hydromorphone exhibited gaiting deficits and biting behavior over the caudal lumbar area above the infusion site. Animals treated with 12 mg/day were sedate and lethargic, and exhibited repeated biting behavior over the caudal lumbar area during the study. No lesions were noted in any animal upon gross evaluation of the spinal cord. Microscopic changes were comparable between hydromorphone- and saline-treated animals with one exception. Mild inflammation 5 cm cranial to the catheter tip was present in two of three sheep receiving 12 mg/day and in one of three sheep receiving 1.5 mg/day. Mild chronic inflammation hydromorphone in the vicinity of the catheter was also presented in saline-treated animals.

CONCLUSIONS

Hydromorphone was not associated with inflammatory mass formation in the sheep model. Further studies are necessary to determine whether hydromorphone is a safer alternative to morphine for continuous intrathecal infusion for the treatment of chronic pain.