Intrathecal Morphine Infusion Research Articles

Long-term intrathecal infusion of low-dose morphine effectively relieves symptoms of severe restless legs syndrome/Willis-Ekbom disease without inducing opioid tolerance.

Restless legs syndrome/Willis-Ekbom disease (RLS/WED) causes a strong urge to move legs while resting. Restless legs syndrome/WED is an often-inherited disease occurring in 3% to 10% of adult populations, increasing with age. Severity varies from mild disturbance of sleep to painful restless legs and arms, loss of sleep, fatigue, and risk of suicide. Dopaminergic drugs relieve symptoms, but cause augmentation, ie, initially helpful but later increase the burden of symptoms. Oral gabapentinoids and opioids are often added, but opioid tolerance and adverse effects are common. With the high prevalence and incomplete help from oral drugs, significant unmet needs exist for effective therapy for severe RLS/WED. Ongoing spinal intrathecal infusion of low-dose morphine is effective, but not generally recognized, as only 12 cases have been published since 2002. We report 7 patients suffering from severe RLS/WED, who had no relief from oral dopaminergic, gabapentinoid, or opioid drugs; they all had excellent relief during ongoing spinal intrathecal infusion of morphine at only 1 to 5 μg/h, ongoing for 1 to 21 years without need of higher doses of morphine.. We suggest that morphine may be transported with the cerebrospinal fluid reaching and readjusting malfunctioning dopamine neuronal systems in the brain and spinal cord. The effects last only as long as the infusion continues. A patient with RLS/WED and persistent genital arousal disorder (PGAD) was relieved of both RLS/WED and PGAD symptoms. These case reports suggest that intrathecal infusion of low-dose morphine is an effective treatment of severe RLS.

Immune response and cytokine profiles in post-laminectomy pain syndrome: comparative analysis after treatment with intrathecal opioids, oral opioids, and non-opioid therapies.

This study explores the interaction between cytokines, cell-mediated immunity (T cells, B cells, and NK cells), and prolonged morphine administration in chronic neuropathic pain patients without cancer-related issues. Despite evidence of opioid immunomodulation, few studies have compared these interactions. In a cross-sectional and comparative study, 50 patients with chronic low back radicular pain ("Failed Back Surgery Syndrome") were categorized into intrathecal morphine infusion (IT group, n = 18), oral morphine (PO group, n = 17), and non-opioid treatment (NO group, n = 15). Various parameters, including plasma and cerebrospinal fluid (CSF) cytokine concentrations, lymphocyte immunophenotyping, opioid escalation indices, cumulative morphine dose, and treatment duration, were assessed. CSF IL-8 and IL-1β concentrations exceeded plasma levels in all patients. No differences in T, B, and NK lymphocyte numbers were observed between morphine-treated and non-treated patients. Higher plasma IL-5 and GM-CSF concentrations were noted in IT and PO groups compared to NO. CSF IFNγ concentrations were higher in PO and NO than IT. Positive correlations included CD4 concentrations with opioid escalation indices, and negative correlations involved NK cell concentrations, CSF TNFα concentrations, and opioid escalation indices. Positive correlations were identified between certain cytokines and pain intensity in IT patients, and between NK cells and cumulative morphine dose. Negative correlations were observed between CSF IL-5 concentrations and pain intensity in IT and PO, and between opioid escalation indices and CSF cytokine concentrations in PO and IT. Associations between cytokines, cellular immunity, and prolonged morphine treatment, administered orally and intrathecally were identified.

Cost-Effectiveness and Cost–Utility Analyses in Thailand of Continuous Intrathecal Morphine Infusion Compared with Conventional Therapy in Cancer Pain: A 10-year Multicenter Retrospective Study

ABSTRACT Background Because of the high initial cost of intrathecal drug delivery (ITDD) therapy, this study investigated the cost-effectiveness and cost–utility of ITDD therapy in refractory cancer pain management in Thailand over the past 10 years. Methods The retrospective study was conducted in patients with cancer pain who underwent ITDD therapy from January 2011 to 2021 at three university hospitals. Clinical outcomes included the numerical rating scale (NRS), Palliative Performance Scale, and the EQ-5D. The direct medical and nonmedical as well as indirect costs were also recorded. Cost-effectiveness and cost–utility analyses were performed comparing ITDD therapy with conventional therapy (extrapolated from costs of the same patient before ITDD therapy) from a societally oriented economic evaluation. Results Twenty patients (F:M: 10:10) aged 60 ± 15 years who underwent implantation of an intrathecal percutaneous port (IT port; n = 15) or programmable intrathecal pump (IT pump; n = 5) were included. The median survival time was 78 (interquartile range = 121–54) days after ITDD therapy. At 2-month follow-up, the incremental cost-effectiveness ratio (ICER)/pain reduction of an IT port (US$2065.36 (CA$2829.54)/2-point NRS reduction/lifetime) was lower than for patients with an IT pump (US$5479.26 (CA$7506.58)/2-point NRS reduction/lifetime) compared with continued conventional therapy. The ICER/quality-adjusted life years (QALYs) gained for an IT port compared with conventional treatment was US$93,999.31(CA$128,799.06)/QALY gained, which is above the cost-effectiveness threshold for Thailand. Conclusion The cost-effectiveness and cost–utility of IT port therapy for cancer pain was high relative to the cost of living in Thailand, above the cost-effectiveness threshold. Prospective cost analysis studies enrolling more patients with diverse cancers that investigate the benefit of early ITDD therapy with devices over a range of prices are warranted.

Intrathecal Morphine Infusion Therapy via a Percutaneous Port for Refractory Cancer Pain in China: An Efficacy, Safety and Cost Utilization Analysis.

PurposeIntrathecal morphine infusion therapy via a percutaneous port (IMITPP) has been used widely for its relatively low initial cost. However, there is scarce knowledge about IMITPP. In this study, we sought to evaluate efficacy, complications, and the interval required to achieve the cost equivalence of IMITPP in patients with refractory cancer pain in China.Patients and MethodsA retrospective chart review was conducted on cancer patients who had received IMITPP at our hospital between April 2017 and April 2019. Data from the numeric pain rating scale and Karnofsky performance scores, and complications and costs related to IMITPP were collected from medical records. Daily analgesic costs before and after IMITPP were calculated based on the doses of opioids on admission and at discharge, respectively. The doses of systemic opioids before IMITPP were stratified into very high doses [VHD, oral morphine equivalent dose (OMED) >599 mg/day], high doses (HD, 300 mg/day ≤ OMED ≤ 599 mg/day), and regular doses (RD, OMED < 300 mg/day).ResultsIntrathecal morphine infusion therapy via a percutaneous port provided significant pain relief, but impaired activities of daily living in patients with refractory cancer pain. The commonly reported complications included nausea/vomiting and urinary retention, most of which were managed with symptomatic therapies. The median interval required to achieve cost equivalence was 11.44 months. The median intervals of VHD group and HD group were significantly shorter than that of RD group.ConclusionIntrathecal morphine infusion therapy via a percutaneous port provided effective cancer pain management without causing serious complications. Patients with higher doses of systemic opioids would economically benefit from IMITPP in a shorter time.

A Mast Cell-Specific Receptor Is Critical for Granuloma Induced by Intrathecal Morphine Infusion.

Intrathecal morphine infusion is often applied to treat chronic pain related to cancer and other conditions. However, persistent pain can be caused by nerve compression because of granuloma formation. In this study, a mouse model of morphine-induced granuloma formation by intrathecal catheterization morphine infusion into the atlanto-occipital membrane of the foramen magnum was established in wild-type mice, MrgprB2 mutant (MrgprB2-/-) mice, and in mast cell-deficient W-sash c-kit mutant (KitW-sh/W-sh) mice. Heat-related pain after surgery was performed to investigate the antipain effect of morphine. H&E staining and immunofluorescence staining of the spinal cord were applied to analyze the mechanism of granuloma formation. Morphine-induced mast cell degranulation was assessed by measuring the Ca2+ influx and mediator release. Anaphylactoid reactions were measured after s.c. morphine infusion to the paws. Chemokine release by mast cells was determined by Human XL Cytokine Array. Experiments with wild-type, MrgprB2 mutant, and mast cell-deficient W-sash c-kit mutant mice demonstrated that morphine activated mast cells and inflammatory cell aggregation through MrgprB2 in intrathecal infusion sites. The chemokine production of human mast cells demonstrated that granuloma formation is correlated with chemokines release. In addition, morphine activated mouse primary mast cells and de novo chemokine synthesis via the MRGPRX2 in human LAD2 cells. We concluded that granuloma formation during intrathecal morphine infusion was associated with MrgprB2/X2. Reducing MRGPRX2 potentially blocks morphine-induced side effects, including granuloma formation.

Characterization of Effect of Repeated Bolus or Continuous Intrathecal Infusion of Morphine on Spinal Mass Formation in the Dog

We determined whether intrathecally delivering the same daily dose of morphine (MS) at a fixed concentration of 25 mg/mL by periodic boluses versus continuous infusion would reduce intrathecal mass (IMs) formation in dogs. Adult dogs (hound cross, n = 32) were implanted with intrathecal catheters connected to SynchroMed II infusion pumps. Animals were randomly assigned to receive infusion of 0.48 mL/day of saline or MS dosing (12 mg/day at 25 mg/mL) as boluses: x1 (q24hour), x2 (q12hour), x4 (q6hour), or x8 (q3hour) given at the rate of 1000 μL/hour, or as a continuous infusion (25 mg/mL/20 μL/hour). With IT saline, minimal pathology was noted. In contrast, animals receiving morphine displayed spinally compressing durally derived masses with the maximal cross-sectional area being greatest near the catheter tip. Histopathology showed that IMs consisted of fibroblasts in a collagen (type 1) matrix comprised of newly formed collagen near the catheter and mature collagen on the periphery of the mass. The rank order of median cross-sectional mass area (mm2 ) was: Saline: 0.7 mm2 ; x2: 1.8 mm2 ; x4: 2.7 mm2 ; x1: 2.7 mm2 ; x8: 4.2 mm2 ; Continuous: 8.1 mm2 , with statistical difference from saline being seen with continuous (p < 0.0001) and x8 (p < 0.05). Bench studies with a 2D diffusion chamber confirmed an increase in dye distribution and lower peak concentrations after bolus delivery versus continuous infusion of dye. Using multiple bolus dosing, IMs were reduced as compared to continuous infusion, suggesting relevance of bolus delivery in yielding reduced intrathecal masses.

Mast Cell Degranulation and Fibroblast Activation in the Morphine-induced Spinal Mass: Role of Mas-related G Protein-coupled Receptor Signaling.

As the meningeally derived, fibroblast-rich, mass-produced by intrathecal morphine infusion is not produced by all opiates, but reduced by mast cell stabilizers, the authors hypothesized a role for meningeal mast cell/fibroblast activation. Using the guinea pig, the authors asked: (1) Are intrathecal morphine masses blocked by opiate antagonism?; (2) Do opioid agonists not producing mast cell degranulation or fibroblast activation produce masses?; and (3) Do masses covary with Mas-related G protein-coupled receptor signaling thought to mediate mast cell degranulation? In adult male guinea pigs (N = 66), lumbar intrathecal catheters connected to osmotic minipumps (14 days; 0.5 µl/h) were placed to deliver saline or equianalgesic concentrations of morphine sulfate (33 nmol/h), 2',6'-dimethyl tyrosine-(Tyr-D-Arg-Phe-Lys-NH2) (abbreviated as DMT-DALDA; 10 pmol/h; μ agonist) or PZM21 (27 nmol/h; biased μ agonist). A second pump delivered subcutaneous naltrexone (25 µg/h) in some animals. After 14 to 16 days, animals were anesthetized and perfusion-fixed. Drug effects on degranulation of human cultured mast cells, mouse embryonic fibroblast activation/migration/collagen formation, and Mas-related G protein-coupled receptor activation (PRESTO-Tango assays) were determined. Intrathecal infusion of morphine, DMT-DALDA or PZM21, but not saline, comparably increased thermal thresholds for 7 days. Spinal masses proximal to catheter tip, composed of fibroblast/collagen type I (median: interquartile range, 0 to 4 scale), were produced by morphine (2.3: 2.0 to 3.5) and morphine plus naltrexone (2.5: 1.4 to 3.1), but not vehicle (1.2: 1.1 to 1.5), DMT-DALDA (1.0: 0.6 to 1.3), or PZM21 (0.5: 0.4 to 0.8). Morphine in a naloxone-insensitive fashion, but not PZM21 or DMT-DALDA, resulted in mast cell degranulation and fibroblast proliferation/collagen formation. Morphine-induced fibroblast proliferation, as mast cell degranulation, is blocked by cromolyn. Mas-related G protein-coupled receptor activation was produced by morphine and TAN67 (∂-opioid agonist), but not by PZM21, TRV130 (mu biased ligand), or DMT-DALDA. Opiates that activate Mas-related G protein-coupled receptor will degranulate mast cells, activate fibroblasts, and result in intrathecal mass formation. Results suggest a mechanistically rational path forward to safer intrathecal opioid therapeutics.

Melatonin regulation of transcription in the reversal of morphine tolerance: Microarray analysis of differential gene expression.

Tolerance and associated hyperalgesia induced by long-term morphine administration substantially restrict the clinical use of morphine in pain treatment. Melatonin, a neurohormone released by the pineal gland, has been demonstrated to attenuate anti-nociceptive morphine tolerance. The present study investigates differentially expressed genes in the process of morphine tolerance and altered gene expression subsequent to melatonin treatment in chronic morphine-infused ratspinal cords. Morphine tolerance was induced in male Wistar rats by intrathecal morphine infusion (the MO group). Melatonin (the MOMa group) was administered to overcome the effects derived by morphine. The mRNA collected from L5-S3 of the spinal cord was extracted and analysed by rat expression microarray. Principal component analysis and clustering analysis revealed that the overall gene profiles were different in morphine and melatonin treatments. Subsequent to Gene Ontology analysis, the biological processes of differentially expressed genes of MO and MOMa compared with the control group were constructed. Furthermore, a panel of genes exclusively expressed following melatonin treatment and another panel of genes with inverse expression between the MO and MOMa group were also established. Subsequent to PANTHER pathway analysis, a group of genes with inverse expression following melatonin administrated compared with morphine alone were identified. The expression levels of genes of interest were also confirmed using a reverse transcription-quantitative polymerase chain reaction. The gene panel that was constructed suggests a potential signaling pathway in morphine tolerance development and is valuable for investigating the mechanism of morphine tolerance and the regulatory gene profiles of melatonin treatment. These results may contribute to the discovery of potential drug targets in morphine tolerance treatments in the future.

445 Continuous Intrathecal Morphine Infusion for Pain Management in a Patient with Burn Injury

445 Continuous Intrathecal Morphine Infusion for Pain Management in a Patient with Burn Injury

Involvement of the N/OFQ-NOP system in rat morphine antinociceptive tolerance: Are astrocytes the crossroad?

The development of tolerance to the antinociceptive effect is a main problem associated with the repeated administration of opioids. The progressively higher doses required to relieve pain reduce safety and exacerbate the side effects of classical opioid receptor agonists like morphine. Nociceptin/orphanin FQ (N/OFQ) and its NOP receptor constitute the fourth endogenous opioid system that is involved in the control of broad spectrum of biological functions, including pain transmission. Aim of this work was to evaluate the relevance of the N/OFQ-NOP system in morphine antinociceptive action and in the development of morphine tolerance in the rat. Continuous spinal intrathecal infusion of morphine (1–3 nmol/h) evoked analgesic effects for 5 days in wild type animals. The same doses infused in NOP(-/-) rats showed a lower analgesic efficacy, while the onset of tolerance was delayed to day 9. N/OFQ (1–3 nmol/h), continuously infused in NOP(+/+) animals, showed an analgesic profile similar to morphine. Immunohistochemical analysis of the dorsal horn of the spinal cord of morphine tolerant NOP(+/+) rats showed an increased number of Iba1- and GFAP-positive cells (microglia and astrocytes, respectively). Interestingly, microglia but not astrocyte activation was observed in NOP(-/-) morphine tolerant rat. A selective activation of astrocytes was observed in the dorsal horn of wild type N/OFQ tolerant rats.The antinociceptive effect of morphine partially depends by the N/OFQ-NOP system that participates in the development of morphine tolerance. In particular, NOP receptors are involved in morphine-induced astrocyte activation, and N/OFQ per se increases astrocyte density.

Role of Neuroinflammation in Opioid Tolerance: Translational Evidence from Human-to-Rodent Studies.

Opioid analgesics remain the most effective and widely used analgesics for the management of moderate to severe pain, including cancer pain and chronic non-cancer pain. However, the efficacy of long-term opioid analgesics is attenuated by tolerance and/or hyperalgesia after long-term use, preventing adequate pain relief under stable opioid dosages for chronic pain patients. Classical neuron-centered concepts about tolerance, such as internalization of opioid receptors, upregulation of N-methyl-D-aspartate receptor function, or downregulation of glutamate transporter activity, can only partially explain the phenomenon of tolerance. Recent evidence revealing glial activation and upregulation of inflammatory mediators in the rodent central nervous system has confirmed the pivotal role of neuroinflammation in neuropathic pain or opioid tolerance, or both. However, human evidence is still sparse.Based on our clinical practice, we conducted translational research by investigating the cerebrospinal fluid (CSF) cytokine and chemokine profiles of opioid-tolerant patients after research ethic committee approval. CSF samples from opioid-tolerant patients and opioid-naive subjects were compared. We found CXCL1, CXCL12, and leukemia inhibitory factor (LIF) were significantly upregulated among the opioid-tolerant patients and positively correlated with the opioid dosage.We translated these findings back to lab animal experiment; after induction of tolerance by morphine infusion, the spinal cord expression of CXCL1, CXCL12, and LIF were all upregulated. Although CXCL1 and CXCL12 infusion alone did not affect baseline tail-flick latency, morphine analgesic efficacy dropped significantly after intrathecal infusion of CXCL1 and CXCL12. After establishing tolerance by intrathecal continuous infusion of morphine, tolerance development was accelerated by co-administration of CXCL1 and CXCL12. In parallel, the effect was attenuated by co-administration of CXCL1- or CXCL12-neutralizing antibody or concordant receptor antagonists.On the contrary, although chronic morphine administration still induced LIF upregulation in rat spinal cords, intrathecal injection of LIF potentiated the analgesic action of morphine and delayed the development of morphine tolerance. Upregulation of endogenously released LIF by long-term use of opioids might counterbalance the tolerance induction effects of other pro-inflammatory cytokines.CXCL1, CXCL12, and LIF are upregulated in both opioid-tolerant patients and rodents. The onset and extent of opioid tolerance were affected by modulating the intrathecal CXCL1/CXCR2, CXCL12/CXCR4, and LIF signaling and could be novel drug targets for the treatment of opioid tolerance.

Spinal Myoclonus Responding to Continuous Intrathecal Morphine Pump.

Spinal myoclonus is a sudden, brief, and involuntary movement of segmental or propriospinal muscle groups. Spinal myoclonus has occasionally been reported in patients undergoing opioid therapy, but the pathophysiology of opioid-induced myoclonus has not been elucidated yet. Here, we present two patients with spinal segmental myoclonus secondary to ischemic and radiation myelopathy. Conventional medications did not help treat persistent myoclonus in both legs. Continuous intrathecal morphine infusion was implanted for pain control in one patient, which relieved spinal myoclonus entirely. This experience led to the application of this method with a second patient, leading to the same gratifying result. Spinal myoclonus reemerged as soon as the morphine pumps were off, which confirmed the therapeutic role of opioids. In contrast to the opioid-induced myoclonus, these cases show a benefit of opioids on spinal myoclonus, which could be explained by synaptic reorganization after pathologic insults in the spinal cord.

CXCL12/CXCR4 Signaling Contributes to the Pathogenesis of Opioid Tolerance: A Translational Study.

Long-term opioid therapy for chronic pain may lead to analgesic tolerance, especially when administered intrathecally, thus preventing adequate pain relief. Discovering drug targets to treat opioid tolerance using a mechanism-based approach targeting opioid-induced neuroinflammation provides new therapeutic opportunities. In this study, we provide translational evidence that CXCL12/CXCR4 signaling contributes to the pathogenesis of opioid tolerance. The CXCL12 levels in the cerebrospinal fluid of opioid-tolerant patients were compared with those of opioid-naive subjects. For further investigation, a rodent translational study was designed using 2 clinically relevant opioid delivery paradigms: daily intraperitoneal morphine injections and continuous intrathecal morphine infusion. We measured rats' tail flick responses and calculated the percentage of maximum possible effects (%MPE) to demonstrate opioid acute antinociception and the development of analgesic tolerance. The effects of exogenous CXCL12, CXCL12 neutralizing antibody, and receptor antagonist AMD3100 were investigated by intrathecal administration. Data were presented as mean ± SEM. CXCL12 was significantly upregulated in the cerebrospinal fluid of opioid-tolerant patients for 892 ± 34 pg/mL (n = 27) versus 755 ± 33 pg/mL (n = 10) in naive control subjects (P = .03). Furthermore, after 2 and 5 days of intrathecal morphine infusion, rat lumbar spinal cord dorsal horn CXCL12 messenger RNA levels were significantly upregulated by 3.2 ± 0.7 (P = .016) and 3.4 ± 0.3 (P = .003) fold, respectively. Results from the daily intraperitoneal morphine injection experiments revealed that administering an intrathecal infusion of CXCL12 for 24 hours before the first morphine injection did not decrease antinociception efficacy on day 1 but accelerated tolerance after day 2 (%MPE 49.5% vs 88.1%, P = .0003). In the intrathecal morphine coinfusion experiments, CXCL12 accelerated tolerance development (%MPE 9.4% vs 43.4% on day 1, P < .0001), whereas coadministration with CXCL12 neutralizing antibody attenuated tolerance (72.5% vs 43.4% on day 1, P < .0001; 47.6% vs 17.5% on day 2, P < .0001). Coadministration of receptor antagonist AMD 3100 can persistently preserve morphine analgesic effects throughout the study period (27.9% ± 4.1% vs 0.9% ± 1.6% on day 5, P = .03). The CXCL12/CXCR4 pathway contributes to the pathogenesis of opioid tolerance. Our study indicates that intervening with CXCL12/CXCR4 signaling has therapeutic potential for opioid tolerance.

Intrathecal Catheterization and Drug Delivery in Guinea Pigs: A Small-animal Model for Morphine-evoked Granuloma Formation.

Intrathecal infusion of opioids in dogs, sheep, and humans produces local space-occupying masses. To develop a small-animal model, the authors examined effects of intrathecal catheterization and morphine infusion in guinea pigs. Under isoflurane, polyethylene or polyurethane catheters were advanced from the cisterna magna to the lumbar enlargement. Drugs were delivered as a bolus through the externalized catheter or continuously by subcutaneous minipumps. Hind paw withdrawal to a thermal stimulus was assessed. Spinal histopathology was systematically assessed in a blinded fashion. To assist in determining catheter placement, ex vivo images were obtained using magnetic resonance imaging in several animals. Canine spinal tissue from previous intrathecal morphine studies was analyzed in parallel. (1) Polyethylene (n = 30) and polyurethane (n = 25) catheters were implanted in the lumbar intrathecal space. (2) Bolus intrathecal morphine produced a dose-dependent (20 to 40 μg/10 μl) increase in thermal escape latencies. (3) Absent infusion, a catheter-associated distortion of the spinal cord and a fibrotic investment were noted along the catheter tract (polyethylene > polyurethane). (4) Intrathecal morphine infusion (25 mg/ml/0.5 μl/h for 14 days) resulted in intrathecal masses (fibroblasts, interspersed collagen, lymphocytes, and macrophages) arising from meninges proximal to the catheter tip in both polyethylene- and polyurethane-catheterized animals. This closely resembles mass histopathology from intrathecal morphine canine studies. Continuous intrathecal infusion of morphine leads to pericatheter masses that morphologically resemble those observed in dogs and humans. This small-animal model may be useful for studying spinal drug toxicology in general and the biology of intrathecal granuloma formation in particular.

Intrathecal chronic morphine infusion pumps for intractable cancer pain: A pilot series in Russia

Intrathecal chronic morphine infusion pumps for intractable cancer pain: A pilot series in Russia

Intrathecal Morphine Infusion Therapy in Management of Chronic Pain: Present and Future Implementation in Korea.

PurposeIntrathecal morphine pump (ITMP) infusion therapy is efficient in managing malignant and nonmalignant chronic pain refractory to standard treatment. However, the high cost of an ITMP is the greatest barrier for starting a patient on ITMP infusion therapy. Using the revised Korean reimbursement guidelines, we investigated the cost effectiveness of ITMP infusion therapy and conducted a patient survey.Materials and MethodsA retrospective chart review of 12 patients who underwent ITMP implantation was performed. Morphine dose escalation rates were calculated, and numeric rating scale (NRS) scores were compared before and after ITMP implantation. We surveyed patients who were already using an ITMP as well as those who were candidates for an ITMP. All survey data were collected through in-person interviews over 3 months. Data on the cost of medical treatment were collected and projected over time.ResultsThe NRS score decreased during the follow-up period. The median morphine dose increased by 36.9% over the first year, and the median time required to reach a financial break-even point was 24.2 months. Patients were more satisfied with the efficacy of ITMP infusion therapy than with conventional therapy. The expected cost of ITMP implantation was KRW 4000000–5000000 in more than half of ITMP candidates scheduled to undergo implantation.ConclusionThe high cost of initiating ITMP infusion therapy is challenging; however, the present results may encourage more patients to consider ITMP therapy.

Ultralow Dose of Naloxone as an Adjuvant to Intrathecal Morphine Infusion Improves Perceived Quality of Sleep but Fails to Alter Persistent Pain: A Randomized, Double-blind, Controlled Study.

This randomized, cross-over, double-blind, controlled study of continuous intrathecal morphine administration in patients with severe, long-term pain addresses whether the supplementation of low doses of naloxone in this setting is associated with beneficial clinical effects. All of the study subjects (n=11) provided informed consent and were recruited from a subset of patients who were already undergoing long-term treatment with continuous intrathecal morphine because of difficult-to-treat pain. The patients were (in a randomized order) also given intrathecal naloxone (40 ng/24 h or 400 ng/24 h). As control, the patients' ordinary dose of morphine without any additions was used. The pain (Numeric Rating Scale, NRS) during activity, perceived quality of sleep, level of activity, and quality of life as well as the levels of several proinflammatory and anti-inflammatory cytokines in the blood were assessed. The prestudy pain (NRS during activity) in the study group ranged from 3 to 10. A total of 64% of the subjects reported improved quality of sleep during treatment with naloxone at a dose of 40 ng per 24 hours as compared with 9% with sham treatment (P=0.024). Although not statistically significant, pain was reduced by 2 NRS steps or more during supplemental treatment with naloxone in 36% of subjects when using the 40 ng per 24 hours dose and in 18% of the subjects when using naloxone 400 ng per 24 hours dose. The corresponding percentage among patients receiving unaltered treatment was 27%. To conclude, the addition of an ultralow dose of intrathecal naloxone (40 ng/24 h) to intrathecal morphine infusion in patients with severe, persistent pain improved perceived quality of sleep. We were not able to show any statistically significant effects of naloxone on pain relief, level of activity, or quality of life.

Intrathecal rapamycin attenuates morphine-induced analgesic tolerance and hyperalgesia in rats with neuropathic pain

Repeated and long-term administration of opioids is often accompanied by the initiation of opioid-induced analgesic tolerance and hyperalgesia in chronic pain patients. Our previous studies showed that repeated intrathecal morphine injection activated the mammalian target of rapamycin complex 1 (mTORC1) in spinal dorsal horn neurons and that blocking this activation prevented the initiation of morphine-induced tolerance and hyperalgesia in healthy rats. However, whether spinal mTORC1 is required for morphine-induced tolerance and hyperalgesia under neuropathic pain conditions remains elusive. We here observed the effect of intrathecal infusion of rapamycin, a specific mTORC1 inhibitor, on morphine-induced tolerance and hyperalgesia in a neuropathic pain model in rats induced by the fifth lumbar spinal nerve ligation (SNL). Continuous intrathecal infusion of morphine for one week starting on day 8 post-SNL led to morphine tolerance demonstrated by morphine-induced reduction in maximal possible analgesic effect (MPAE) to tail heat stimuli and ipsilateral paw withdrawal threshold (PWT) to mechanical stimuli in SNL rats. Such reduction was attenuated by co-infusion of rapamycin. Co-infusion of rapamycin also blocked morphine tolerance demonstrated by attenuation of morphine-induced reduction in MPAE in sham rats and morphine-induced hyperalgesia demonstrated by the reverse of morphine-induced reduction in PWT on both sides of sham rats and on the contralateral side of SNL rats. The results suggest that mTORC1 inhibitors could serve as promising medications for use as adjuvants with opioids in clinical neuropathic pain management.

Intrathecal morphine versus epidural ropivacaine infusion for analgesia after Cesarean section: a retrospective study.

BackgroundAnalgesia after Cesarean delivery (CD) requires early ambulation to prevent thromboembolic disease and to facilitate baby care. We retrospectively reviewed anesthesia charts and medical records of patients who underwent CD to compare the efficacy of spinal anesthesia supplemented with intrathecal morphine hydrochloride (ITM) and combined spinal–epidural anesthesia followed by opioid-free epidural analgesia (CSEA-EDA).FindingsAll subjects underwent CD at Nagaoka Chuo General Hospital between February 2012 and January 2013. Patient characteristics, time to first analgesic rescue after CD, and analgesic use after CD were examined. Incidences of postural hypotension, lower extremity numbness/weakness, postoperative nausea/vomiting (PONV), and pruritus were also examined for 48 h after CD. Average time to first analgesic use after CD (ITM 25.13 ± 16.07 h, CSEA-EDA 22.42 ± 16.27 h, p = 0.521) and cumulative probability of rescue analgesic use (p = 0.139 by log-rank test) were comparable between groups. However, average analgesic use within 24 h was lower in the ITM group (0.75 ± 1.05 times) than in the CSEA-EDA group (1.52 ± 1.72 times, p = 0.0497). Numbness or motor weakness in lower extremities only occurred in the CSEA-EDA group, and pruritus only occurred in the ITM group.ConclusionsThe results of this study suggest that ITM is better than CSEA-EDA for anesthesia following CD with regard to pain control. Also, ITM would be advantageous for early ambulation following CD because of lower incidence of numbness and motor weakness in lower extremities compared to CSEA-EDA.

(367) Intrathecal morphine infusion therapy in management of cancer and chronic pain: present and future in Korea

(367) Intrathecal morphine infusion therapy in management of cancer and chronic pain: present and future in Korea