Methods: Thirty-two patients undergoing elective AH were randomised into Group ITM (ITM 0.2 mg + 2.5 mL 0.5% bupivacaine) (n = 16) and Group EB (0.25% bupivacaine bolus + continuous infusion of 0.1% bupivacaine-fentanyl 2 μg/mL) (n = 16).The procedure was performed before induction, and all patients subsequently received standard general anaesthesia. Both groups were provided patient-controlled analgaesia morphine (PCAM) as a backup. Visual analogue scale (VAS) scores, total morphine consumption, hospital stay duration, early mobilisation time and first PCAM demand time were recorded.
Results: The median VAS score was lower for ITM than for EB after the 1st hour [1.0 (IqR 1.0) versus 3.0 (IqR 3.0), P < 0.001], 8th hour [1.0 (IqR 1.0) versus 2.0 (IqR 1.0), P = 0.018] and 16th hour [1.0 (IqR1.0) versus (1.0 (IqR 1.0), P = 0.006]. The mean VAS score at the 4th hour was also lower for ITM [1.8 (SD 1.2) versus 2.9 (SD 1.4), P = 0.027]. Total morphine consumption [11.3 (SD 6.6) versus 16.5 (SD 4.8) mg, P = 0.016] and early mobilisation time [2.1 (SD 0.3) versus 2.6 (SD 0.9) days, P = 0.025] were also less for ITM. No significant differences were noted for other assessments.
Conclusions: The VAS score was better for ITM than for EB at earlier hours after surgery. However, in terms of acceptable analgaesia (VAS ≤ 3), both techniques were comparable over 24 hours.
OBJECTIVES: The present study was performed to investigate the discriminative stimulus effects of MG in rats. The pharmacological mechanism of MG action and its derivative, 7-hydroxymitragynine (7-HMG) with a specific focus on opioid receptor involvement was examined in rats trained to discriminate morphine from vehicle. In order to study the dual actions of MG, the effect of cocaine substitution to the MG discriminative stimulus was also performed in MG-trained rats.
METHODS: Male Sprague Dawley rats were trained to discriminate MG from vehicle in a two-lever drug discrimination procedure under a tandem variable-interval (VI 60') fixed-ratio (FR 10) schedule of food reinforcement.
RESULTS: Rats acquired the MG discrimination (15.0 mg/kg, i.p.) which was similar to the acquisition of morphine discrimination (5.0 mg/kg, i.p.) in another group of rats. MG substituted fully to the morphine discriminative stimulus in a dose-dependent manner, suggesting pharmacological similarities between the two drugs. The administration of 7-HMG derivative in 3.0 mg/kg (i.p.) dose engendered full generalisation to the morphine discriminative stimulus. In addition, the MG stimulus also partially generalised to cocaine (10.0 mg/kg, i.p.) stimulus.
CONCLUSION: The present study demonstrates that the discriminative stimulus effect of MG possesses both opioid- and psychostimulant-like subjective effects.
OBJECTIVES: We aimed to examine the cognitive effects of mitragynine substitution in morphine-withdrawn rats. Furthermore, we asked whether neuronal addiction markers like the brain-derived neurotrophic factor (BDNF) and Ca2+/calmodulin-dependent kinase II alpha (αCaMKII) might mediate the observed effects.
METHODS: Male Sprague-Dawley rats were given morphine at escalating doses before treatment was discontinued to induce a spontaneous morphine withdrawal. Then, vehicle or mitragynine (5 mg/kg, 15 mg/kg, or 30 mg/kg) substitution was given for 3 days. A vehicle-treated group was used as a control. Withdrawal signs were scored after 24 h, 48 h, and 72 h, while novel object recognition (NOR) and attentional set-shifting (ASST) were tested during the substitution period.
RESULTS: Discontinuation of morphine significantly induced morphine withdrawal signs and cognitive deficit in the ASST. The substitution with mitragynine was able to alleviate the withdrawal signs. Mitragynine did not affect the recognition memory in the NOR but significantly improved the reversal learning deficit in the morphine-withdrawn rats.
CONCLUSIONS: These data support the idea that mitragynine could be used as safe medication therapy to treat opiate addiction with beneficial effects on cognitive deficits.
Purpose: To determine the level of adherence to opioid analgesics in patients with cancer pain and to identify factors that may influence the adherence.
Patient and Methods: This was a cross-sectional study conducted from March to June 2018 at two tertiary care hospitals in Malaysia. Study instruments consisted of a set of validated questionnaires; the Medication Compliance Questionnaire, Brief Pain Inventory and Pain Opioid Analgesic Beliefs─Cancer scale.
Results: A total of 134 patients participated in this study. The patients' adherence scores ranged from 52-100%. Factors with a moderate, statistically significant negative correlation with adherence were negative effect beliefs (rs= -0.53, p<0.001), pain endurance beliefs (rs = -0.49, p<0.001) and the use of aqueous morphine (rs = -0.26, p=0.002). A multiple linear regression model on these predictors resulted in a final model which accounted for 47.0% of the total variance in adherence (R2 = 0.47, F (7, 126) = 15.75, p<0.001). After controlling for other variables, negative effect beliefs were the strongest contributor to the model (β = -0.39, p<0.001) and uniquely explained 12.3% of the total variance.
Conclusion: The overall adherence to opioid analgesics among Malaysian patients with cancer pain was good. Negative effects beliefs regarding cancer pain and opioids strongly predicted adherence.
AIM: To investigate the attitudes and perceptions of morphine use in cancer pain in advanced cancer patients and their caregivers and to examine the influence of caregivers' attitudes and perceptions on patients' acceptance of morphine.
DESIGN: Qualitative study involving semi-structured individual interviews transcribed verbatim and analyzed thematically.
SETTING/PARTICIPANTS: A total of 18 adult opioid-naïve patients with advanced cancer and 13 caregivers (n = 31) were recruited at a private tertiary hospital via convenience sampling.
RESULTS: Attitudes and perceptions of morphine were influenced by previous experiences. Prevalent themes were similar in both groups, including perceptions that morphine was a strong analgesic that reduced suffering, but associated with end-stage illness and dependence. Most participants were open to future morphine use for comfort and effective pain control. Trust in doctors' recommendations was also an important factor. However, many preferred morphine as a last resort because of concerns about side effects and dependence, and the perception that morphine was only used at the terminal stage. Caregivers' attitudes toward morphine did not affect patients' acceptance of morphine use.
CONCLUSION: Most participants were open to future morphine use despite negative perceptions as they prioritized optimal pain control and reduction of suffering. Focused education programs addressing morphine misperceptions might increase patient and caregiver acceptance of opioid analgesics and improve cancer pain control.
SETTING: Hospital surgical ward.
SUBJECTS: Women (107 Indian, 184 Malay, and 750 Han Chinese) undergoing total hysterectomy surgery.
METHODS: Morphine consumption, preoperative pain, and postoperative pain were evaluated in relation to genetic variability comprising 19 single-nucleotide polymorphisms (SNPs) in 14 genes involved in glial activation, inflammatory signaling, and neuronal regulation, plus OPRM1 (1 SNP) and COMT (3 SNPs).
RESULTS: Pre- and postoperative pain and age were associated with increased and decreased morphine consumption, respectively. In Chinese patients, only 8% of the variability in consumption could be explained by these nongenetic and genetic (BDNF, IL1B, IL6R, CRP, OPRM1, COMT, MYD88) factors. However, in Indian patients, 41% of morphine consumption variability could be explained by age (explaining <3%) and variants in OPRM1 rs1799971, CRP rs2794521, TLR4 rs4986790, IL2 rs2069762, COMT rs4818, TGFB1 rs1800469, and IL6R rs8192284 without controlling for postoperative pain.
CONCLUSIONS: This is the highest known value reported for genetic contributions (38%) to morphine use in the acute postoperative pain setting. Our findings highlight the need to incorporate both genetic and nongenetic factors and consider ethnicity-dependent and nonadditive genotypic models in the assessment of factors that contribute to variability in opioid use.