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Neuropsychopharmacology : Official... Sep 2018Cannabinoids combined with opioids produce synergistic antinociceptive effects, decreasing the lowest effective antinociceptive opioid dose (i.e., opioid-sparing... (Randomized Controlled Trial)
Randomized Controlled Trial
Cannabinoids combined with opioids produce synergistic antinociceptive effects, decreasing the lowest effective antinociceptive opioid dose (i.e., opioid-sparing effects) in laboratory animals. Although pain patients report greater analgesia when cannabis is used with opioids, no placebo-controlled studies have assessed the direct effects of opioids combined with cannabis in humans or the impact of the combination on abuse liability. This double-blind, placebo-controlled, within-subject study determined if cannabis enhances the analgesic effects of low dose oxycodone using a validated experimental model of pain and its effects on abuse liability. Healthy cannabis smokers (N = 18) were administered oxycodone (0, 2.5, and 5.0 mg, PO) with smoked cannabis (0.0, 5.6% Δ tetrahydrocannabinol [THC]) and analgesia was assessed using the Cold-Pressor Test (CPT). Participants immersed their hand in cold water (4 °C); times to report pain (pain threshold) and withdraw the hand from the water (pain tolerance) were recorded. Abuse-related effects were measured and effects of oxycodone on cannabis self-administration were determined. Alone, 5.0 mg oxycodone increased pain threshold and tolerance (p ≤ 0.05). Although active cannabis and 2.5 mg oxycodone alone failed to elicit analgesia, combined they increased pain threshold and tolerance (p ≤ 0.05). Oxycodone did not increase subjective ratings associated with cannabis abuse, nor did it increase cannabis self-administration. However, the combination of 2.5 mg oxycodone and active cannabis produced small, yet significant, increases in oxycodone abuse liability (p ≤ 0.05). Cannabis enhances the analgesic effects of sub-threshold oxycodone, suggesting synergy, without increases in cannabis's abuse liability. These findings support future research into the therapeutic use of opioid-cannabinoid combinations for pain.
Topics: Adult; Analgesia; Analgesics, Opioid; Double-Blind Method; Dronabinol; Drug Synergism; Female; Humans; Male; Marijuana Smoking; Middle Aged; Opioid-Related Disorders; Oxycodone; Pain Measurement; Young Adult
PubMed: 29463913
DOI: 10.1038/s41386-018-0011-2 -
Bioengineered Apr 2022Endothelial dysfunction is an important mechanism involved in myocardial ischemia-reperfusion (I/R) injury. We aimed to explore the effects of Oxycodone on myocardial...
Endothelial dysfunction is an important mechanism involved in myocardial ischemia-reperfusion (I/R) injury. We aimed to explore the effects of Oxycodone on myocardial I/R injury in vivo and in vitro to reveal its mechanisms related to Sigma-1 Receptor (SIGMAR1). A rat model of I/R-induced myocardial injury was developed. The ischemic area and myocardial histopathological changes after oxycodone addition were evaluated by TTC staining and H&E staining. LDH, CK-MB and cTnI levels were used to assess myocardial function. Then, the endothelial integrity was reflected by the expressions of ZO-1, Claudin-1 and Occludin. Afterward, ELISA, RT-qPCR, western blot and immunofluorescence assays were adopted for the detection of inflammation-related genes. SIGMAR1 expression in myocardial tissues induced by I/R and cardiac microvascular endothelial cells (CMECs) under hypoxic/reoxygenation (H/R) was determined using RT-qPCR and western blotting. Subsequently, after SIGMAR1 silencing or BD1047 addition (a SIGMAR1 antagonist), cell apoptosis and endothelial integrity were analyzed in the presence of Oxycodone in H/R-stimulated CMECs. Results indicated that Oxycodone decreased the ischemic area and improved myocardial function in myocardial I/R injury rat. Oxycodone improved myocardial histopathological injury and elevated endothelial integrity, evidenced by upregulated ZO-1, Claudin-1 and Occludin expressions. Moreover, inflammatory response was alleviated after Oxycodone administration. Molecular docking suggested that SIGMAR1 could directly bind to Oxycodone. Oxycodone elevated SIGMAR1 expression and SIGMAR1 deletion or BD1047 addition attenuated the impacts of Oxycodone on apoptosis and endothelial integrity of CMECs induced by H/R. Collectively, Oxycodone alleviates myocardial I/R injury in vivo and in vitro by binding to SIGMAR1.
Topics: Animals; Apoptosis; Claudin-1; Endothelial Cells; Molecular Docking Simulation; Myocardial Reperfusion Injury; Myocytes, Cardiac; Occludin; Oxycodone; Rats; Receptors, sigma; Sigma-1 Receptor
PubMed: 35412431
DOI: 10.1080/21655979.2022.2057632 -
Neuropharmacology Mar 2021Antagonism of peripheral opioid receptors by methylnaltrexone (MNTX) was recently proposed as a potential mechanism to attenuate the development of opioid analgesic...
BACKGROUND
Antagonism of peripheral opioid receptors by methylnaltrexone (MNTX) was recently proposed as a potential mechanism to attenuate the development of opioid analgesic tolerance based on experiments conducted in mice. However, reports indicate that MNTX is demethylated to naltrexone (NTX) in mice, and NTX may subsequently cross the blood-brain barrier to antagonize centrally-mediated opioid effects. The goal of this study was to determine whether MNTX alters centrally-mediated behaviors elicited by the opioid analgesics, morphine and oxycodone, and to quantify concentrations of MNTX and NTX in blood and brain following their administration in mice.
METHODS
Combinations of MNTX and morphine were tested under acute and chronic conditions in thermal nociceptive assays. Effects of MNTX and NTX pretreatment were assessed in an oxycodone discrimination operant procedure. Blood and brain concentrations of these antagonists were quantified after their administration using liquid chromatography-mass spectrometry.
RESULTS
MNTX dose-dependently attenuated acute and chronic morphine antinociception. MNTX and NTX dose-dependently antagonized the discriminative stimulus effects of oxycodone. MNTX and NTX were detected in both blood and brain after administration of MNTX, confirming its demethylation and demonstrating that MNTX itself can cross the blood-brain barrier.
CONCLUSIONS
These results provide converging behavioral and analytical evidence that MNTX administration in mice attenuates centrally-mediated effects produced by opioid analgesics and results in functional concentrations of MNTX and NTX in blood and brain. Collectively, these findings indicate that MNTX cannot be administered systemically in mice for making inferences that its effects are peripherally restricted.
Topics: Analgesics, Opioid; Animals; Blood-Brain Barrier; Dose-Response Relationship, Drug; Male; Mice; Mice, Inbred C57BL; Morphine; Naltrexone; Narcotic Antagonists; Oxycodone; Pain Measurement; Quaternary Ammonium Compounds
PubMed: 33316279
DOI: 10.1016/j.neuropharm.2020.108437 -
Neuropharmacology Mar 2021Opioid use disorder is a leading cause of morbidity and mortality in the United States. Increasing pre-clinical and clinical evidence demonstrates sex differences in...
Opioid use disorder is a leading cause of morbidity and mortality in the United States. Increasing pre-clinical and clinical evidence demonstrates sex differences in opioid use and dependence. However, the underlying molecular mechanisms contributing to these effects, including neuroinflammation, are still obscure. Therefore, in this study, we investigated the effect of oxycodone exposure and withdrawal on sex- and region-specific neuroimmune response. Real-time PCR and multiplex cytokine array analysis demonstrated elevated neuroinflammation with increased pro-inflammatory cytokine levels, and aberrant oligodendroglial response in reward neurocircuitry, following withdrawal from chronic oxycodone treatment. Chronic oxycodone and withdrawal treated male mice had lower mRNA expression of TMEM119 along with elevated protein levels of pro-inflammatory cytokines/chemokines and growth factors (IL-1β, IL-2, IL-7, IL-9, IL-12, IL-15, IL17, M-CSF, VEGF) in the prefrontal cortex (PFC) as compared to their female counterparts. In contrast, reduced levels of pro-inflammatory cytokines/chemokines (IL-1β, IL-6, IL-9, IL-12, CCL11) was observed in the nucleus accumbens (NAc) of oxycodone and withdrawal-treated males as compared to female mice. No treatment specific effects were observed on the mRNA expression of putative microglial activation markers (Iba1, CD68), but an overall sex specific decrease in the mRNA expression of Iba1 and CD68 was found in the PFC and NAc of male mice as compared to females. Moreover, a sex and region-specific increase in the mRNA levels of oligodendrocyte lineage markers (NG2, Sox10) was also observed in oxycodone and withdrawal treated animals. These findings may open a new avenue for the development of sex-specific precision therapeutics for opioid dependence by targeting region-specific neuroimmune signaling.
Topics: Analgesics, Opioid; Animals; Female; Male; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Neuroimmunomodulation; Oxycodone; Prefrontal Cortex; Sex Characteristics; Substance Withdrawal Syndrome
PubMed: 33485944
DOI: 10.1016/j.neuropharm.2021.108469 -
Neuropharmacology Apr 2023Recent evidence suggests that inhibition of the M muscarinic acetylcholine receptor (mAChR) may provide a novel non-opioid mechanism for the treatment of opioid use...
Recent evidence suggests that inhibition of the M muscarinic acetylcholine receptor (mAChR) may provide a novel non-opioid mechanism for the treatment of opioid use disorder (OUD). Previous studies from our group and others have demonstrated that acute administration of the long-acting M negative allosteric modulator (NAM) ML375 attenuates established self-administration of cocaine, ethanol, oxycodone, and remifentanil in rats. In the present study, we characterized the effects of acute and repeated administration of the novel, short-acting M NAM VU6008667 on the reinforcing effects of oxycodone and reinstatement of oxycodone-seeking behaviors in male Sprague-Dawley rats, as well as on physiological withdrawal from oxycodone. Acute VU6008667 decreased oxycodone self-administration under both fixed ratio 3 (FR3) and progressive ratio (PR) schedules of reinforcement and attenuated cue-induced reinstatement of lever pressing following extinction from oxycodone self-administration, a commonly used relapse model. When administered daily to opioid-naïve rats, VU6008667 prevented acquisition of oxycodone self-administration behavior. VU6008667 had minimal effects on naloxone-precipitated withdrawal. After acute administration, VU6008667 did not inhibit sucrose self-administration and, when given chronically, delayed but did not prevent acquisition of sucrose maintained self-administration. VU6008667 also did not impact oxycodone induced anti-nociception or motor coordination, but mildly decreased novelty exploration. Finally, acute or daily VU6008667 administration did not impair cued fear conditioning. Overall, these results suggest that inhibition of the M mAChR may provide a novel, non-opioid based treatment for distinct aspects of OUD by inhibiting opioid intake in established OUD, reducing relapse during abstinence, and by reducing the risk of developing OUD.
Topics: Animals; Male; Rats; Analgesics, Opioid; Opioid-Related Disorders; Oxycodone; Rats, Sprague-Dawley; Receptors, Muscarinic; Self Administration; Sucrose
PubMed: 36720403
DOI: 10.1016/j.neuropharm.2023.109424 -
Addiction Biology Mar 2022Traumatic brain injury (TBI) and drug addiction are common comorbidities, but it is unknown if the neurological sequelae of TBI contribute to this relationship. We have...
Traumatic brain injury (TBI) and drug addiction are common comorbidities, but it is unknown if the neurological sequelae of TBI contribute to this relationship. We have previously reported elevated oxycodone seeking after drug self-administration in rats that received repeated blast TBI (rbTBI). TBI and exposure to drugs of abuse can each change structural and functional neuroimaging outcomes, but it is unknown if there are interactive effects of injury and drug exposure. To determine the effects of TBI and oxycodone exposure, we subjected rats to rbTBI and oxycodone self-administration and measured drug seeking and several neuroimaging measures. We found interactive effects of rbTBI and oxycodone on fractional anisotropy (FA) in the nucleus accumbens (NAc) and that FA in the medial prefrontal cortex (mPFC) was correlated with drug seeking. We also found an interactive effect of injury and drug on widespread functional connectivity and regional homogeneity of the blood oxygen level dependent (BOLD) response, and that intra-hemispheric functional connectivity in the infralimbic medial prefrontal cortex positively correlated with drug seeking. In conclusion, rbTBI and oxycodone self-administration had interactive effects on structural and functional magnetic resonance imaging (MRI) measures, and correlational effects were found between some of these measures and drug seeking. These data support the hypothesis that TBI and opioid exposure produce neuroadaptations that contribute to addiction liability.
Topics: Animals; Brain Concussion; Drug-Seeking Behavior; Neuroimaging; Oxycodone; Rats; Self Administration
PubMed: 35229952
DOI: 10.1111/adb.13134 -
Neuropharmacology Jun 2019Growing nonmedical use of prescription opioids is a global problem, motivating research on ways to reduce use and combat addiction. Medical cannabis ("medical...
Growing nonmedical use of prescription opioids is a global problem, motivating research on ways to reduce use and combat addiction. Medical cannabis ("medical marijuana") legalization has been associated epidemiologically with reduced opioid harms and cannabinoids have been shown to modulate effects of opioids in animal models. This study was conducted to determine if Δ-tetrahydrocannabinol (THC) enhances the behavioral effects of oxycodone. Male rats were trained to intravenously self-administer (IVSA) oxycodone (0.15 mg/kg/infusion) during 1 h, 4 h or 8 h sessions. Following acquisition rats were exposed to THC by vapor inhalation (1 h and 8 h groups) or injection (0-10 mg/kg, i.p.; all groups) prior to IVSA sessions. Fewer oxycodone infusions were obtained by rats following vaporized or injected THC compared with vehicle treatment prior to the session. Follow-up studies demonstrated parallel dose-dependent effects of THC, i.p., on self-administration of different per-infusion doses of oxycodone and a preserved loading dose early in the session. These patterns are inconsistent with behavioral suppression. Additional groups of male and female Wistar rats were assessed for nociception following inhalation of vaporized THC (50 mg/mL), oxycodone (100 mg/mL) or the combination. Tail withdrawal latency was increased more by the THC/oxycodone combination compared to either drug alone. Similar additive antinociceptive effects were produced by injection of THC (5.0 mg/kg, i.p.) and oxycodone (2.0 mg/kg, s.c.). Together these data demonstrate additive effects of THC and oxycodone and suggest the potential use of THC to enhance therapeutic efficacy, and to reduce the abuse, of opioids.
Topics: Analgesics, Opioid; Animals; Cannabinoids; Dronabinol; Female; Male; Nociception; Oxycodone; Pain Threshold; Rats; Rats, Wistar; Self Administration
PubMed: 30980837
DOI: 10.1016/j.neuropharm.2019.04.010 -
British Journal of Clinical Pharmacology Apr 2017This study aimed to characterize the pharmacokinetics of oxycodone and its major metabolites in infants and covered the age range between extremely preterm neonates and... (Clinical Trial)
Clinical Trial
AIMS
This study aimed to characterize the pharmacokinetics of oxycodone and its major metabolites in infants and covered the age range between extremely preterm neonates and 2-year-old infants.
METHODS
Seventy-nine infants (gestational age 23-42 weeks; postnatal age 0-650 days) received intravenous oxycodone hydrochloride trihydrate at a dose of 0.1 mg kg during or after surgery. Three to seven blood samples were taken from each infant, and plasma concentrations of oxycodone, noroxycodone, oxymorphone, and noroxymorphone were quantified. The unconjugated forms of these compounds were determined in urine collected after up to 24 or 48 h from 25 infants. Pharmacokinetics was determined using noncompartmental analysis and reported for six clinically relevant age groups based on postmenstrual age.
RESULTS
Oxycodone pharmacokinetics changed markedly with patient age. Preterm neonates were found to have the highest pharmacokinetic variability out of the study population. In extremely preterm neonates (n = 6) median of elimination half-life was 8.8 h (range 6.8-12.5), in preterm (n = 11) 7.4 h (4.2-11.6), and in older neonates (n = 22) 4.1 h (2.4-5.8), all of which were significantly longer than that in infants aged 6-24 months (n = 12) 2.0 h (1.7-2.6). Median renal clearance was fairly constant in all age groups, whereas non-renal clearance markedly increased with age. Noroxycodone was the major metabolite in plasma and urine.
CONCLUSIONS
Oxycodone elimination is slower and pharmacokinetic variability more pronounced in neonates when compared to older infants. These findings highlight the importance of careful dose titration for neonates.
Topics: Age Factors; Analgesics, Opioid; Child, Preschool; Female; Half-Life; Humans; Infant; Infant, Extremely Premature; Infant, Newborn; Infant, Premature; Male; Morphinans; Oxycodone; Prospective Studies; Time Factors
PubMed: 27780305
DOI: 10.1111/bcp.13164 -
Annals of Palliative Medicine Jan 2021Opioid titration is the best way to achieve a balance of pain relief and tolerable side effects for moderate-to-severe cancer pain. Rapid dose titration helps to achieve... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Opioid titration is the best way to achieve a balance of pain relief and tolerable side effects for moderate-to-severe cancer pain. Rapid dose titration helps to achieve early analgesia. We explored the efficacy and safety of a 12-hour rapid dose titration in treating cancer pain.
METHODS
Opioid-naïve patients with moderate-to-severe cancer pain were randomly divided into oxycodone group and morphine group. The medicines were adjusted to oxycodone sustained-release tablets after 12 hours, and the dose of oxycodone sustained-release tablets was adjusted every 12 hours. The analgesic efficacy and adverse reactions during the treatment were observed until the 72nd hour.
RESULTS
A total of 106 patients were included in the analysis, with 51 patients in the oxycodone group and 55 in the morphine group. The pain control rate of all patients reached 96.2% 24 hours after treatment, and it was not significantly different between two groups (P=0.619). The proportion of Numeric Rating Scale (NRS) score that decreased by ≥50% was significantly higher in the oxycodone group than in the morphine group (P=0.013). In the first 12 hours and 24 hours, significantly lower proportions of patients in the oxycodone group experienced multiple episodes of breakthrough pain (BTP) than in the morphine group (P=0.032, P=0.021, respectively). The quality of life of the patients in the oxycodone group was significantly higher than that in the morphine group at the 24th hour (P=0.047), as was the degree to which the quality of life had improved (P<0.001). Only grade 1 or 2 adverse reactions were observed during the study period, and no significant difference between two groups.
CONCLUSIONS
The 12-hour rapid dose titration method can achieve early analgesia, with mild adverse reactions. In particular, the rapid titration method with background sustained-release oxycodone can reduce BTP episodes and achieve significant early pain relief.
Topics: Analgesics, Opioid; Cancer Pain; Humans; Morphine; Neoplasms; Oxycodone; Quality of Life
PubMed: 33474955
DOI: 10.21037/apm-20-2336 -
Drugs in R&D Jun 2016Oxycodone is the mo st commonly used opioid for the treatment of moderate to severe pain. The peak cerebrospinal fluid concentration after epidural oxycodone was... (Comparative Study)
Comparative Study
BACKGROUND AND OBJECTIVES
Oxycodone is the mo st commonly used opioid for the treatment of moderate to severe pain. The peak cerebrospinal fluid concentration after epidural oxycodone was reported to be 300-fold greater (0.025 mM) than when administered intravenously after gynecologic surgery. Additionally, those patients administered epidural oxycodone had lower pain scores, needed less rescue analgesics and had fewer adverse effects compared with intravenous administration. However, oxycodone neurotoxicity requires evaluation before intrathecal implementation for routine clinical use.
METHODS
We used two in vitro cell culture models to compare the cytotoxicity of oxycodone with that of morphine, and to study the mechanisms underlying toxicity. Human neuroblastoma cells and mouse motoneuronal cells were treated with increasing concentrations (0.0125-2 mM) of oxycodone or morphine, and were harvested at 24, 48 or 96 h. Cell cultures were evaluated with 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide and resazurin reduction assays.
RESULTS
Both morphine and oxycodone decreased cell viability in a dose-dependent manner at concentrations between 0.5 and 2 mM. Morphine increased the number of apoptotic cells compared with oxycodone when assessed by flow cytometry, and transmission electron microscopy images revealed that exposure to both opioids evoked the appearance of numerous electron-dense, probable autophagic vacuoles in the cytoplasm of the cells.
CONCLUSIONS
Based on these results, it seems that the cytotoxicity of oxycodone in motoneuronal cells is similar to or less than that of morphine, and occurs only at concentrations above the peak clinical concentration in the cerebrospinal fluid after epidural administration.
Topics: Analgesics, Opioid; Animals; Cell Line; Cell Survival; Drug Therapy, Combination; Flow Cytometry; Humans; Mice; Morphine; Motor Neurons; Neuroblastoma; Neurotoxicity Syndromes; Oxycodone
PubMed: 26913723
DOI: 10.1007/s40268-016-0125-0