OBJECTIVE To demonstrate the efficacy and safety of the addition of bupivacaine in restoring pain control and improving quality of life and activity level in patients with chronic nonmalignant pain refractory to intrathecal opioids. DESIGN Retrospective study. SETTING Outpatient clinics. PATIENTS Seventeen patients with inadequate pain relief while receiving intrathecal opioids alone. Int...

Chen, Shao-Rui and Hui-Lin Pan. Loss of TRPV1-expressing sensory neurons reduces spinal opioid receptors but paradoxically potentiates opioid analgesia. J Neurophysiol 95: 3086–3096, 2006. First published February 8, 2006; doi:10.1152/jn.01343.2005. Systemic administration of resiniferatoxin (RTX), an ultrapotent capsaicin analogue, removes transient receptor potential vanilloid type 1 (TRPV1)-...

BACKGROUND Neuropathic pain is associated with several sensory abnormalities, including allodynia as well as spontaneous pain. Opioid intake in neuropathic pain patients is motivated by alleviation of both pain and allodynia. However, laboratory animal studies rely almost exclusively on reflexive withdrawal measures of allodynia. The authors examined the pharmacology of self-regulated intake of...

BACKGROUND Despite decades of intense research efforts, actions of acute opioids are not fully understood. Increasing evidence suggests that in addition to well-documented antinociceptive effects opioids also produce paradoxical hyperalgesic and excitatory effects on neurons. However, most studies focus on the pronociceptive actions of chronic opioid exposure. Matrix metalloproteinase 9 (MMP-9)...

Study Design: Case report. Patient Sample: A 42year-old Caucasian male. Results: Catheter-tip granuloma formation is possible despite a normal catheter access study in patients with intrathecal (IT) infusion systems and its recurrence is possible after surgical excision. Increasing concentrations of hydromorphone from 50 mg/ml to 100 mg/ml without altering the daily dosage may have precipitated...

Background: The endocannabinoid system interacts with the vanilloid and opioid systems. The current study aims to investigate the effects of the extract obtained from the heated Cannabis Sativa female flower base either with capsaicin at the spinal cord level or naloxone at the systemic level on the intensity of chemical and thermal pain sensation. Methods: This experimental study was performe...

Cesarean section (CS) is one of the most common surgical procedures in female patients. We aimed to evaluate the postoperative analgesic efficacy of intrathecal fentanyl during the period of greatest postoperative analgesic demand after CS. This period was defined by detailed analysis of patient-controlled analgesia (PCA) usage.This double-blind, placebo-controlled, parallel-group randomized tr...

Although the importance of the nucleus raphe magnus in descending inhibitory control of nociception is clear, it is not known whether these effects are equivalent for different types of nociception. Thus, we examined the differential inhibition of behavioral responses evoked by A or C fiber thermonociceptor activation by electrical stimulation of nucleus raphe magnus neurons as well as the invo...

Many clinical case reports have suggested that sustained opioid exposure can elicit unexpected, paradoxical pain. Here, we explore the possibility that (1) opioid-induced pain results from tonic activation of descending pain facilitation arising in the rostral ventromedial medulla (RVM) and (2) the presence of such pain manifests behaviorally as antinociceptive tolerance. Rats implanted subcuta...

BACKGROUND Although intrathecal administration of opioids produces antinociceptive effects in the spinal cord, it has not been established whether intrathecal opioid application more effectively terminates C fiber-mediated pain than A fiber-mediated pain. Here, the authors focus on the differences in opioid actions on Adelta- and C-afferent responses. METHODS Using the whole cell patch clamp ...