Dezocine. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy

Synthesis of Primary Amines via Hydrogen Atom Transfer-Initiated Cyclization/Reduction Cascade of Unsaturated Nitriles

We report a hydrogen atom transfer-initiated cyclization/reduction cascade for the synthesis of primary amines from δ,ε- and ε,ζ-unsaturated nitriles. The HAT transformation employs Mn(acac)3 as a catalyst and utilizes air as an oxidant along with NaBH4 as a dual-purpose reductant toward the olefin and subsequently C═N. Aromatic and aliphatic nitriles incorporating mono-, di-, and trisubstituted olefins are substrates for the reaction. Starting materials bearing malonates are transformed into the corresponding bicyclic lactams, enabling the rapid buildup of structural complexity.

Bis-Cyclic Guanidine Heterocyclic Peptidomimetics as Opioid Ligands with Mixed μ-, κ- and δ-Opioid Receptor Interactions: A Potential Approach to Novel Analgesics

The design and development of analgesics with mixed-opioid receptor interactions has been reported to decrease side effects, minimizing respiratory depression and reinforcing properties to generate safer analgesic therapeutics. We synthesized bis-cyclic guanidine heterocyclic peptidomimetics from reduced tripeptides. In vitro screening with radioligand competition binding assays demonstrated variable affinity for the mu-opioid receptor (MOR), delta-opioid receptor (DOR), and kappa-opioid receptor (KOR) across the series, with compound 1968-22 displaying good affinity for all three receptors. Central intracerebroventricular (i.c.v.) administration of 1968-22 produced dose-dependent, opioid receptor-mediated antinociception in the mouse 55 °C warm-water tail-withdrawal assay, and 1968-22 also produced significant antinociception up to 80 min after oral administration (10 mg/kg, p.o.). Compound 1968-22 was detected in the brain 5 min after intravenous administration and was shown to be stable in the blood for at least 30 min. Central administration of 1968-22 did not produce significant respiratory depression, locomotor effects or conditioned place preference or aversion. The data suggest these bis-cyclic guanidine heterocyclic peptidomimetics with multifunctional opioid receptor activity may hold potential as new analgesics with fewer liabilities of use.

Dezocine as a potent analgesic: overview of its pharmacological characterization

Dezocine, a synthetic opioid, introduced in 1970s as an analgesic, was redeveloped for relieving moderate to severe pain by Yangtze River Pharmaceutical Group in China in 2009. To date, dezocine occupies 45% of China's opioid analgesic market. Along with dezocine being a dominated painkiller, a certain amount of research was conducted to elucidate dezocine's action. In this review we summarize the current knowledge on the receptor, preclinical and clinical pharmacology of dezocine. Briefly, preclinical data show that dezocine is effective under varying pain conditions, particularly chronic neuropathic pain and cancer pain, through activation of opioid receptors, and inhibition of norepinephrine reuptake. Clinical data establish the effectiveness of dezocine either as a primary analgesic for postoperative pain management or a supplement for balanced analgesia. The receptor profile of dezocine is different from known pure μ agonists, and allows it to be used in combination with other opioids for additivity in efficacy or lower incidence of adverse effects.

Dezocine Has the Potential to Regulate the Clinical and Biological Features of Tumors

Cancer is the second leading cause of death following ischemic heart disease in the world and the primary clinical, social and economic burden. Surgical resection is the main measure for the treatment of the vast majority of solid tumors. However, the recurrence and metastasis of tumors occur at different periods after surgery in many cases undergoing radical tumor surgery, which is the main cause of death of tumor patients. Moreover, tumor patients are prone to suffer from mental depression, which may increase the morbidity and mortality of tumors. Tumors have a series of clinical biological signs with the following five main features: postoperative pain and cancerous pain; suppression of antitumor immunity; angiogenesis in tumors; proliferation, growth and metastasis of tumors; and mental depression. Surgery is the first treatment in the majority of cancer patients with solid tumors. Opioids are required for anesthesia and postoperative analgesia. For cancerous pain control, patients undergo surgery, and their quality of life of is improved. However, traditional opioids, such as morphine, may inhibit antitumor immunity, induce vascular growth of tumors and promote the proliferation, invasion and migration of cancer cells, and traditional opioids can induce a risk of somatic dependence. However, studies have found that not all opioids share the effects of immunosuppression, tumor proliferation promotion and angiogenesis induction. Dezocine, a novel opioid with specific pharmacological mechanisms, has been demonstrated to regulate the five clinical and biological features of tumors. We reviewed the preclinical and clinical studies of dezocine on postoperative pain and cancer pain in tumor patients as well as the immune system, tumor angiogenesis, tumor proliferation, tumor growth, tumor metastasis and mental depression. We proposed that dezocine may be the best choice of opioids for anesthesia and analgesia in cancer patients.

Efficacy of dezocine on preventing opioid-induced cough during general anaesthesia induction: a PRISMA-compliant systematic review and meta-analysis

OBJECTIVES

To systematically review the effects of dezocine (DZC) on the occurrence rate and severity of opioid-induced cough (OIC).

DESIGN

Systematic review and meta-analysis DATA SOURCES: PubMed, Embase, Cochrane Library, Ovid, Web of Science as well as Chinese BioMedical Literature & Retrieval System, China National Knowledge Infrastructure, Wanfang and VIP Data were searched from 1978 to 31 December 2020.

INCLUSION CRITERIA

All randomised controlled trials (RCTs) comparing DZC with placebo on the occurrence rate and severity of OIC.

DATA ANALYSIS

All data were analysed by using RevMan V.5.3. Each outcome was tested for heterogeneity, and randomised-effects or fixed-effects model was used in the presence or absence of significant heterogeneity.

RESULTS

Our search yielded 33 RCTs including 4442 patients, and 2521 patients were allocated into the DZC group and 1921 into the control group. Fentanyl was administrated in 1880 patients and sufentanil in 2562 patients during the induction of general anaesthesia. The meta-analysis demonstrated that DZC significantly reduced the occurrence rate of OIC induced by either fentanyl (8.8% vs 49.7%, OR=0.07, 95% CI 0.04 to 0.12, p<0.00001) or sufentanil (5.0% vs 41.5%, OR=0.07, 95% CI 0.04 to 0.12, p<0.00001). The meta-analysis also indicated that the occurrence rate of mild, moderate and severe OIC in the DZC group was remarkably lower than that of the control group (mild: 3.6% vs 13.6%, OR=0.19, 95% CI 0.14 to 0.25, p<0.00001; moderate: 2.0% vs 13.6%, OR=0.12, 95% CI 0.09 to 0.18, p<0.00001; severe: 1.0% vs 13.9%, OR=0.08, 95% CI 0.05 to 0.12, p<0.00001). Additionally, the current meta-analysis indicated that DZC pretreatment was not associated with increased occurrence rate of adverse effects (7.0% vs 4.2%, OR=2.34, 95% CI 0.60 to 9.14, p=0.22) except for dizziness (11.8% vs 0%, OR=8.06, 95% CI 1.40 to 46.35, p=0.02).

CONCLUSION

This meta-analysis demonstrated that DZC significantly inhibited OIC and may be used to manage OIC. More high-quality RCTs are needed to complement the safety of DZC.

PROSPERO REGISTRATION NUMBER

CRD42019141255.

The protective effects of dezocine on interleukin-1β-induced inflammation, oxidative stress and apoptosis of human nucleus pulposus cells and the possible mechanisms

Intervertebral disc degeneration (IDD) is a natural problem linked to the inflammation. We aimed to investigate the role of dezocine (DEZ) in the development of IDD. Human nucleus pulposus cells (HNPCs) induced by interleukin (IL)-1β was used as a cellular model of IDD. After treatment with DEZ, HNPCs viability was evaluated with a CCK-8 assay. Then, the levels of inflammatory factors, including IL-6 and tumor necrosis factor-α (TNF-α), and oxidative stress-related markers, including reactive oxygen species (ROS), malondialdehyde (MDA) and reduced glutathione (GSH), were tested by RT-qPCR or kits. TUNEL staining was employed to detect cell apoptosis and Western blot was used to determine the expression of proteins related to inflammation, oxidative stress, apoptosis, endoplasmic reticulum stress (ERS) and MAPK signaling. Afterward, PMA, a MAPK signaling pathway agonist, was adopted for exploring the regulatory effects of DEZ on MAPK pathway. Results indicated that DEZ enhanced cell viability of HNPCs after IL-1β exposure. DEZ alleviated the inflammation and oxidative stress, evidenced by decreased levels of IL-6, TNF-α, ROS, MDA, p-NF-κB p65, NF-κB p65 in nucleus, cox-2 and increased levels of NF-κB p65 in cytoplasm, GSH, SOD1 and SOD2. Moreover, DEZ notably inhibited IL-1β-induced apoptosis of HNPCs. Furthermore, DEZ suppressed the levels of ERS-related proteins. The levels of related proteins in MAPK signaling including p-P38 and p-ERK1/2 were remarkably reduced after DEZ administration. By contrast, PMA crippled the impacts of DEZ on inflammation, oxidative stress and apoptosis of HNPCs induced by IL-1β. Collectively, DEZ ameliorates IL-1β-induced HNPCs injury via inhibiting MAPK signaling.

Comparative study of dezocine, pentazocine and tapentadol on antinociception and physical dependence

AIMS

Dezocine and pentazocine, widely prescribed in China for postoperative pain, were initially considered as mixed agonist/antagonist targeting μ-opioid receptors (MORs) and κ-opioid receptors (KORs). However, dezocine has been revealed to alleviate chronic neuropathic pain through MOR activation and norepinephrine reuptake inhibition (NRI). This study investigated dezocine- and pentazocine-induced antinociception and physical dependence development, compared to the typical MOR-NRI opioid tapentadol.

MAIN METHODS

Calcium mobilization assay was conducted to assess the potency of the drugs while hot-plate test was performed to compare the antinociception. Physical dependence development was compared with morphine.

KEY FINDINGS

Treatment with dezocine, pentazocine and tapentadol stimulated calcium mobilization in HEK293 cells stably expressed MORs but not KORs, whereas dezocine and pentazocine inhibited KOR activities. Subcutaneously injected dezocine-, tapentadol- and pentazocine-induced antinociception dose-dependently, in hot-plate test. Intrathecally injected MOR antagonist CTAP, norepinephrine depletor 6-OHDA and α₂-adrenoceptor (α₂-AR) antagonist yohimbine partially antagonized dezocine, pentazocine and tapentadol antinociception. Whereas specific KOR antagonist GNTI did not alter their antinociception, the putative inverse KOR agonist nor-BNI reduced dezocine and pentazocine antinociception. Moreover, combined CTAP and 6-OHDA or yohimbine blocked dezocine and tapentadol antinociception but displayed the same partial inhibition on pentazocine antinociception as CTAP alone. Furthermore, compared to morphine and pentazocine, long-term treatment with dezocine and tapentadol produced much less physical dependence-related withdrawal signs, which were restored by spinal 6-OHDA or yohimbine treatment.

SIGNIFICANCE

Our findings illustrated that dezocine and tapentadol, but not pentazocine, exert remarkable antinociception in nociceptive pain with less abuse liability via dual mechanisms of MOR activation and NRI.

Simultaneous Determination of Celecoxib, Dezocine and Dexmedetomidine in Beagle Plasma Using UPLC-MS/MS Method and the Application in Pharmacokinetics

Background

An efficient, fast and sensitive ultra high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method for simultaneous determination of celecoxib (CEL), dezocine (DEZ) and dexmedetomidine (DEX) in beagle plasma were established.

Methods

The beagle dogs plasmawas precipitated by acetonitrile. The column was Acquity UPLC BEH C18 column and the mobile phase was acetonitrile-formic acid with gradient mode, and the flow rate was set at 0.4 mL/min. Under the positive ion mode, CEL, DEZ, DEX and Midazolam (internal standard, IS) were monitored by multiple reaction monitoring (MRM) as the following mass transition pairs: m/z 381.10→282.10 for CEL, m/z 246.20→147.00 for DEZ, m/z 201.10→94.90 for DEX, and m/z 326.10→291.10 for IS.

Results

This UPLC-MS/MS method had good linearity for CEL, DEZ and DEX. The RSDs of inter-day and intra-day precision were the values of 0.31–7.66% and 0.11–9.63%, respectively; the RE values were from −6.05% to 10.98%. The extraction recovery was more than 79%, and the matrix effect was around 100%. The RSDs of stability were less than 8.96%. All of them met the acceptance standard of biological analysis method recommended by FDA.

Conclusion

This UPLC-MS/MS method is an effective tool for the simultaneous determination of CEL, DEX and DEX, and has been successfully applied to the study of pharmacokinetics in beagle dogs.

"I'll Be Back": The Resurrection of Dezocine

Beginning with opium itself, natural and synthetic opioids have been used as analgesics for over 8000 years and were likely abused as drugs of recreation for that long as well. However, the "opioid crisis" resulted in attempts to avoid or limit opioid analgesics in favor of other therapies and methods. Mu opioid agonists can be effective analgesics but suffer from addiction, tolerance, and dangerous, sometimes fatal, side effects. One exception to this generalization is dezocine (Dalgan), a mixed mu/kappa opioid partial agonist. Dezocine is at least as effective as morphine in reducing acute pain in animal models and clinical applications such as postoperative pain. And while dezocine was discontinued in western markets in 2011, it has become the favored opioid analgesic in China, capturing over 40% of the market. Additionally, dezocine possesses norepinephrine uptake inhibitory activity, which may synergize with mu agonism in the case of acute pain treatment and possibly endow the drug with antinociceptive activity in neuropathic pain conditions. This Innovations article summarizes the history and properties of dezocine and presents evidence and rationale for why dezocine has undergone a resurrection.

Is dezocine effective and safe in preventing opioids-induced cough during general anaesthesia induction? A protocol for systematic review and meta-analysis

INTRODUCTION

Cough is often observed when administrating a bolus of opioids. Opioid-induced cough (OIC) is mostly transient, benign and self-limiting, but could be associated with adverse effects. Numerous pharmacological and non-pharmacological interventions have been used to manage OIC with controversial efficacy and safety. Recent studies suggested that, pretreatment of intravenous dezocine (DZC) could completely suppress OIC during anaesthesia induction. To address this knowledge lack, we will perform a systemic review and meta-analysis to evaluate the efficacy of DZC on OIC and possible complications. We provide here a protocol that will outline the methods and analyses planned for the systematic review.

METHODS

PubMed, Embase, Cochrane Library, Web of Science as well as Chinese BioMedical Literature & Retrieval System (SinoMed), China National Knowledge Infrastructure, Wanfang Data and VIP Data will be searched from 1978 to 31 December 2019 to identify all randomised controlled trials comparing DZC with placebo on the incidence and severity of OIC. Primary outcomes of interest include the incidence and severity of OIC. Secondary outcomes of interest include possible complications or adverse effects of DZC. Two authors will independently extract relevant variables and outcome data. For continuous variables, treatment effects will be calculated as weighted mean difference and 95% CI. For dichotomous data, treatment effects will be calculated as OR and 95% CI. Each outcome will be tested for heterogeneity, and randomised-effects or fixed-effects model will be used in the presence or absence of significant heterogeneity. Sensitivity analyses will be done by examining the influence of statistical model and individual trial(s) on estimated treatment effects. Publication bias will be explored through visual inspection of funnel plots of the outcomes. Statistical significance will be defined as p<0.05.

ETHICS AND DISSEMINATION

This study is a protocol of meta-analysis of previously published literatures, ethical approval was not necessary according to the Ethical Committee of Fuwai Hospital. The study will be submitted to a peer-reviewed journal and disseminated via research presentations.

PROSPERO REGISTRATION NUMBER

CRD42019141255.

Postoperative analgesia using dezocine alleviates depressive symptoms after colorectal cancer surgery: A randomized, controlled, double-blind trial

BACKGROUND

Postoperative depression is one of the most common mental disorders in patients undergoing cancer surgery and it often delays postoperative recovery. We investigated whether dezocine, an analgesic with inhibitory effect on the serotonin and norepinephrine reuptake, could relieve postoperative depressive symptoms in patients undergoing colorectal cancer surgery.

METHODS

This randomized, controlled, single-center, double-blind trial was performed in the Second Affiliated Hospital of the Army Medical University. A total of 120 patients were randomly assigned to receive either sufentanil (1.3 μg/kg) with dezocine (1 mg/kg) (dezocine group; n = 60) or only sufentanil (2.3 μg/kg) (control group; n = 60) for patient-controlled intravenous analgesia after colorectal cancer surgery. The primary outcome was the Beck Depression Inventory score at 2 days after surgery. The secondary outcomes included the Beck Anxiety Inventory, sleep quality, and quality of recovery scores.

RESULTS

Compared with those in the control group, patients in the dezocine group had lower depression scores (7.3±3.4 vs. 9.9±3.5, mean difference 2.6, 95% CI: 1.4-3.9; P<0.001) at 2 days after surgery and better night sleep quality at the day of surgery (P = 0.010) and at 1 day after the surgery (P<0.001). No significant difference was found in other outcomes between the two groups.

CONCLUSIONS

Intravenous analgesia using dezocine can relieve postoperative depression symptoms and improve sleep quality in patients undergoing colorectal cancer surgery.

Dezocine promotes T lymphocyte activation and inhibits tumor metastasis after surgery in a mouse model

Dezocine is an opioid analgesic with both μ-receptor agonist and antagonist activities. Administration of opioids influences the immune system through immune cells. Dendritic cells (DC) play crucial functions in inducing T cell response and mediating immune functions. DC surface displays several different opioid receptors whose expression is induced during DC maturation. We aimed to explore the effects of dezocine on DCs and T cells, as well as on tumor treatment. Mice were intraperitoneally administrated with increasing doses of dezocine (0.75, 1.25 and 2.0 mg/kg). Mouse bone marrow-derived dendritic cells (BMDCs) were then isolated from the bone marrow. The BMDC surface markers were evaluated by flow cytometry. T cell proliferation was assessed by the carboxyfluorescein succinimidyl ester assay. The number of mature DCs were increased by dezocine treatment in both human umbilical cord blood and mouse peripheral blood, suggesting that dezocine enhanced BMDC maturation. Dezocine-treated BMDCs promoted CD8+ T cell proliferation and cytotoxicity, while dezocine treatment inhibited tumor metastasis in mice. We therefore conclude that the administration of dezocine promotes BMDC maturation and inhibits tumor metastasis through elevating CD8+ T cell proliferation and cytotoxicity.

Effect of Scalp Nerve Block with Ropivacaine on Postoperative Pain in Patients Undergoing Craniotomy: A Randomized, Double Blinded Study

Scalp nerve block with ropivacaine has been shown to provide perioperative analgesia. However, the best concentration of ropivacaine is still unknown for optimal analgesic effects. We performed a prospective study to evaluate the effects of scalp nerve block with varied concentration of ropivacaine on postoperative pain and intraoperative hemodynamic variables in patients undergoing craniotomy under general anesthesia. Eighty-five patients were randomly assigned to receive scalp block with either 0.2% ropivacaine, 0.33% ropivacaine, 0.5% ropivacaine, or normal saline. Intraoperative hemodynamics and post-operative pain scores at 2, 4, 6, 24 hours postoperatively were recorded. We found that scalp blockage with 0.2% and 0.33% ropivacaine provided adequate postoperative pain relief up to 2 h, while administration of 0.5% ropivacaine had a longer duration of action (up to 4 hour after craniotomy). Scalp nerve block with varied concentration of ropivacaine blunted the increase of mean arterial pressure in response to noxious stimuli during incision, drilling, and sawing skull bone. 0.2% and 0.5% ropivacaine decreased heart rate response to incision and drilling. We concluded that scalp block using 0.5% ropivacaine obtain preferable postoperative analgesia compared to lower concentrations. And scalp block with ropivacaine also reduced hemodynamic fluctuations in craniotomy operations.

Combination of propofol and dezocine to improve safety and efficacy of anesthesia for gastroscopy and colonoscopy in adults: A randomized, double-blind, controlled trial

BACKGROUND

Gastroscopy and colonoscopy are important and common endoscopic methods for the diagnosis and treatment of gastrointestinal and colorectal diseases. However, endoscopy is usually associated with adverse reactions such as nervousness, nausea, vomiting, choking cough, and pain. Severe discomfort, such as vomiting, coughing, or body movement, may lead to aggravation of a pre-existing condition or even interruption of examination or treatment, especially in some critically ill patients with physiological dysfunction (e.g., cardiovascular or respiratory disease). The optimal methods for inducing analgesia and sedation in endoscopy are areas of ongoing debate; nevertheless, determining an appropriate regimen of sedation and analgesia is important.

AIM

To evaluate the effects of propofol combined with dezocine, sufentanil, or fentanyl in painless gastroscopy and colonoscopy.

METHODS

Four hundred patients were randomly assigned to one of four groups for anesthesia: intravenous dezocine, sufentanil, fentanyl, or saline. Propofol was administered intravenously for induction and maintenance of anesthesia.

RESULTS

The dosage of propofol in the dezocine group was significantly lower than those in other groups (P < 0.01). Bispectral index and Steward score (0-6 points, an unresponsive, immobile patient whose airway requires maintenance to a fully recovered patient) after eye opening in the dezocine group were significantly higher than those in other groups (P < 0.01). Awakening time and postoperative pain score (0-10 points, no pain to unbearable pain) in the dezocine group were significantly lower than those in other groups (P < 0.01). Mean arterial pressure and pulse oxygen saturation in the dezocine group were significantly more stable at various time points (before dosing, disappearance of eyelash reflex, and wakeup) than those in other groups (P < 0.01). The rates of hypopnea, jaw thrust, body movements, and usage of vasoactive drugs in the dezocine group were significantly lower than those in other groups (P < 0.01). Additionally, the rates of reflex coughing, nausea, and vomiting were not statistically different between the four groups (P > 0.05).

CONCLUSION

The combination of propofol and dezocine can decrease propofol dosage, reduce the risk for the development of inhibitory effects on the respiratory and cardiovascular systems, increase analgesic effect, decrease body movement, shorten awakening time, and improve awakening quality.

Pharmacological Characterization of Dezocine, a Potent Analgesic Acting as a κ Partial Agonist and μ Partial Agonist

Dezocine is becoming dominated in China market for relieving moderate to severe pain. It is believed that Dezocine’s clinical efficacy and little chance to provoke adverse events during the therapeutic process are mainly attributed to its partial agonist activity at the μ opioid receptor. In the present work, we comprehensively studied the pharmacological characterization of Dezocine and identified that the analgesic effect of Dezocine was a result of action at both the κ and μ opioid receptors. We firstly found that Dezocine displayed preferential binding to μ opioid receptor over κ and δ opioid receptors. Dezocine, on its own, weakly stimulated G protein activation in cells expressing κ and μ receptors, but in the presence of full κ agonist U50,488 H and μ agonist DAMGO, Dezocine inhibited U50,488H- and DAMGO-mediated G protein activation, indicating that Dezocine was a κ partial agonist and μ partial agonist. Then the in intro results were verified by in vivo studies in mice. We observed that Dezocine-produced antinociception was significantly inhibited by κ antagonist nor-BNI and μ antagonist β-FNA pretreatment, indicating that Dezocine-mediated antinociception was via both the κ and μ opioid receptors. When co-administrating of Dezocine with U50,488 H or morphine, Dezocine was capable of inhibiting U50,488H- or morphine-induced antinociception. Finally, κ receptor activation-associated side effect sedation was investigated. We found that Dezocine displayed limited sedative effect with a ceiling effecting at a moderate dose. Thus, our work led to a better understanding of the analgesic mechanism of action of Dezocine in vivo.

Additive analgesic effect of dexmedetomidine and dezocine administered intrathecally in a mouse pain model

Background

It is known that dexmedetomidine can reduce opioid requirements and that there is a synergistic effect when dexmedetomidine and morphine (a full mu opioid receptor agonist) are administered together. However, it was unclear whether a synergistic or additive effect would be observed when dexmedetomidine was co-administered with a partial mu opioid receptor agonist. The present study was designed to elucidate such effects by intrathecally co-administering dexmedetomidine and dezocine, a partial mu receptor agonist, in a mouse pain model.

Methods

C57 mice (N = 165) were randomly divided into 19 groups. The tail flick test was adopted to measure the antinociceptive effects of the tested agents. The mice were divided into saline and drug groups to investigate the dose-dependent analgesic effects. Each drug was administered at fixed doses alone and in combination with one of three doses of a second drug.

Results

Dezocine (0.3125 - 1.25 μg) and dexmedetomidine (0.04 - 1 μg) both enhanced the tail withdrawal latency in dose-dependent fashions. Dexmedetomidine (0.04 - 1 μg) enhanced the analgesic effect of dezocine. Dezocine (0.3125 - 1.25 μg) enhanced the analgesic effect of dexmedetomidine. Compared with the individual drug effects, the combined effects of dezocine (0.625 μg) and dexmedetomidine (0.04 μg) were more potent 15 - 60 min after injection, but they remained similar to the sum of the effects of the two individual drugs.

Conclusions

Dexmedetomidine and dezocine produce an additive analgesic effect on acute nociception when administered simultaneously.

Antinociceptive effects of dezocine on complete Freund's adjuvant-induced inflammatory pain in rats

Inflammatory pain is known to severely impact the life quality of patients. Notably, dezocine is widely used for the treatment of pain. Therefore, the current study aimed to examine the effects of dezocine on a complete Freund's adjuvant (CFA)-induced inflammatory pain model in rats and to investigate the possible underlying molecular mechanisms. Rats were randomly divided into three groups, including the control, CFA and dezocine+CFA groups, and then subcutaneously injected with 100 µl saline, subcutaneously injected with 100 µl CFA or pretreated with 1 ml dezocine (0.4 µg/kg) at 30 min before CFA injection in the plantar surface of right hind paw, respectively. The paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were measured with a dynamic plantar esthesiometer at 1 day before and 6 h after CFA injection. The ipsilateral lumbar spinal cords of all the rats were harvested for detecting the expression profiles of phosphorylated (p)-p65, p-extracellular signal-regulated kinase 1/2 (p-ERK1/2), cyclooxygenase-2 (COX-2), interleukin (IL)-1β and tumor necrosis factor (TNF)-α by western blot analysis and/or reverse transcription-quantitative polymerase chain reaction. In addition, prostaglandin E2 (PGE2) expression was determined by enzyme-linked immunosorbent assay. Compared with the control group, CFA-induced peripheral inflammation downregulated the PWT and PWL values of rats, which were significantly alleviated by dezocine treatment. Furthermore, the protein levels of p-p65, p-ERK1/2, COX-2, PGE2, IL-1β and TNF-α were significantly upregulated following CFA injection, while they were suppressed by dezocine pretreatment. In conclusion, the analgesic effect of dezocine on inflammatory pain induced by CFA may be associated with the inhibition of the spinal ERK1/2-COX-2 pathway.

A single dose of dezocine suppresses emergence agitation in preschool children anesthetized with sevoflurane-remifentanil

Background

Emergence agitation (EA) is a common phenomenon in preschool children during emergence from general anesthesia. This study evaluated the safety and efficacy of dezocine for emergence agitation in preschool children anesthetized with sevoflurane-remifentanil.

Methods

A total of 100 preschool children, scheduled for elective laparoscopic repair of an inguinal hernia by high ligation of the hernia sac under sevoflurane-remifentanil anesthesia were randomized into two groups: Group C (n = 50) received Ringer’s lactate 10 mL and Group D received Ringer’s lactate 10 mL containing dezocine 0.1 mg/kg, postoperatively.

Results

Incidence of EA, defined as a score ≥ 3 on Aono’s four point scale or Pediatric Anesthesia Emergence Delirium (PAED) score ≥ 10 in the PACU (10% vs. 76%) and the percentage of patients with severe EA (PAED score ≥ 13) (12% vs. 76%) were significantly lower in Group D compared to Group C (P < 0.05). Mean Children and Infants Postoperative Pain Scale (CHIPPS) score was significantly lower in Group D compared to Group C (1.2 ± 0.5 vs. 5.2 ± 0.6; P < 0.05). Patients need for fentanyl (18% vs. 4%) or propofol rescue (20% vs. 0) was significantly greater in Group C compared to Group D. No significant differences in other relative aspects after surgery between groups.

Conclusion

Administration of dezocine 0.1 mg/kg decreased the incidence and severity of EA in preschool children that had undergone laparoscopic repair of an inguinal hernia by high ligation of the hernia sac under sevoflurane-remifentanil anesthesia.

Trial registration

A single dose of dezocine suppresses emergence agitation in preschool children anesthetized with sevoflurane-remifentanil effectively: A double-blind, prospective, randomized, controlled study, Chinese Clinical Trial Registry (ID: ChiCTR-IOR-16010033), retrospectively registered on November 21, 2016.

Stability study of dezocine in 0.9% sodium chloride solutions for patient-controlled analgesia administration

BACKGROUND

Dezocine, a mixed agonist/antagonist of opioid receptors, has been used in iv patient-controlled analgesia (PCA) pumps for postoperative pain control. The aim of this study was to investigate the physicochemical stability of dezocine solutions in 0.9% sodium chloride for injection for PCA administration.

METHODS

Solutions of dezocine (0.3, 0.45, or 0.6 mg/mL in 0.9% sodium chloride for injection) were stored in polyolefin bags and glass bottles. Their stabilities at storage conditions of 4°C for 14 days and 25°C for 72 hours were studied. For all preparations, physical characteristics (including pH, color, and presence of precipitates) were evaluated. Each preparation of dezocine was also analyzed using a stability-indicating high-performance liquid chromatography method. A solution was considered stable if it maintained at least 90% of its initial concentration.

RESULTS

No notable changes in pH, color, or precipitation were observed in any of the prepared solutions over the testing period. All formulations maintained >97% of the initial dezocine concentration under the storage conditions evaluated.

CONCLUSIONS

Dezocine solutions at 0.3, 0.45, or 0.6 mg/mL in 0.9% sodium chloride for PCA administration were stable for 72 hours at 25°C and for 14 days at 4°C when packaged in polyolefin bags or glass bottles and protected from light.

Dezocine for Preventing Postoperative Pain: A Meta-Analysis of Randomized Controlled Trials

Background

Dezocine is considered to be an alternative medication for managing postoperative pain. The aim of this study was to assess the efficacy and safety of this drug in this regard.

Methods

Medline, EMBASE and the Cochrane Central Register of Control Trials (CENTRAL) were searched to identify all randomized controlled trials (RCTs) that compare dezocine with placebo or dezocine with morphine on postoperative pain. The data were extracted and pooled using Mantel-Haenszel random effects model. Heterogeneity was tested using the I² statistic with values >50% and Chi² test with P ≤ 0.05 indicating obvious heterogeneity between the studies.

Results

Seven trials evaluating 665 patients were included. The number of patients with at least 50% pain relief was increased (N = 234; RR 3.04, 95% CI 2.27 to 4.08) and physician (N = 465; RR 2.84, 95% CI 1.66 to 4.84) and patient satisfaction (N = 390; RR 2.81, 95% CI 1.85 to 4.26) were improved following the administration of dezocine compared with the placebo. The effects of dezocine were similar to those of morphine in terms of the number of patients reporting at least 50% pain relief within 2–6 h after surgery (N = 235; RR 1.29, 95% CI 1.15 to 1.46) and physician (N = 234; RR 1.18, 95% CI 0.93 to 1.49) and patient (N = 158; RR 1.33, 95% CI 0.93 to 1.92) satisfaction. While, the number of patients with at least 50% pain relief within 0–1 h after surgery increased following dezocine compared with morphine treatment (N = 79; RR 1.45, 95% CI 1.18 to 1.77). There was no difference in the incidence of postoperative nausea and vomiting (PONV) following dezocine treatment compared with the placebo (N = 391; RR 1.06, 95% CI 0.42 to 2.68) or morphine treatment (N = 235; RR 0.65, 95% CI 0.14 to 2.93).

Conclusion

Dezocine is a promising analgesic for preventing postoperative pain, but further studies are required to evaluate its safety.

Dezocine Prevents Postoperative Hyperalgesia in Patients Undergoing Open Abdominal Surgery

Objective. Postoperative hyperalgesia is very frequent and hard to treat. Dezocine is widely used and has a modulatory effect for thermal hyperalgesia in animal models. So, this study was designed to investigate the potential role of dezocine in decreasing postoperative hyperalgesia for patients undergoing open abdominal surgery. Methods. This is a randomized, double-blinded, and placebo-controlled trial. 50 patients for elective open gastrectomy were randomly allocated to either a true treatment group (0.15 mg/kg intravenous dezocine at the end of surgery) or a sham treatment group (equivalent volume of saline) in a 1 : 1 ratio. Patients were followed up for 48 hours postoperatively and pain threshold to Von Frey filaments, pain scores, PCIA consumption, rescue analgesics use, sedation score, and occurrence of postoperative nausea and vomiting were recorded. Results. Patients in the true treatment group experienced statistically significantly higher pain threshold on forearm and smaller extent of peri-incisional hyperalgesia than the sham treatment group. Rescue analgesic use, cumulative PCIA consumption, and pain scores were statistically significantly decreased in the true treatment group compared to the sham treatment group. Conclusions. Dezocine offers a significant antihyperalgesic and analgesic effect in patients undergoing elective open gastrectomy for up to 48 hours postoperatively.

Parallel Synthesis of Hexahydrodiimidazodiazepines Heterocyclic Peptidomimetics and Their in Vitro and in Vivo Activities at μ (MOR), δ (DOR), and κ (KOR) Opioid Receptors

In the development of analgesics with mixed-opioid agonist activity, peripherally selective activity is expected to decrease side effects, minimizing respiratory depression and reinforcing properties generating significantly safer analgesic therapeutics. We synthesized diazaheterocyclics from reduced tripeptides. In vitro screening with radioligand competition binding assays demonstrated variable affinity for μ (MOR), δ (DOR), and κ (KOR) opioid receptors across the series, with the diimidazodiazepine 14 (2065-14) displaying good affinity for DOR and KOR. Central (icv), intraperitoneal (ip), or oral (po) administration of 14 produced dose-dependent, opioid-receptor mediated antinociception in the mouse, as determined from a 55 °C warm-water tail-withdrawal assay. Only trace amounts of compound 14 was found in brain up to 90 min later, suggesting poor BBB penetration and possible peripherally restricted activity. Central administration of 14 did not produce locomotor effects, acute antinociceptive tolerance, or conditioned-place preference or aversion. The data suggest these diazaheterocyclic mixed activity opioid receptor agonists may hold potential as new analgesics with fewer liabilities of use.

Pharmaceuticals that contain polycyclic hydrocarbon scaffolds

This review comprehensively explores approved pharmaceutical compounds that contain polycyclic scaffolds and the properties that these skeletons convey.

Intravenous dezocine pretreatment reduces the incidence and intensity of myoclonus induced by etomidate

To evaluate the suppressive effect of intravenous dezocine on the incidence and severity of myoclonic movements induced by etomidate, a total of 80 patients, American Society of Anesthesiologists physical status I-II, were randomized into two equally sized groups (n = 40). These two groups were assigned to give either intravenous dezocine 0.1 mg/kg or a matching placebo (equal volume of 0.9% saline) 30 s before administration of etomidate. For anesthesia induction, 0.3 mg/kg etomidate was injected over a period of 1 min. One minute after etomidate administration, the severity of myoclonus was assessed. Pretreatment with dezocine significantly reduced both the incidence and intensity of myoclonus. These results demonstrate that intravenous dezocine 0.1 mg/kg 30 s prior to induction was effective in suppressing myoclonic movements in our patients.

Preoperative administration of intramuscular dezocine reduces postoperative pain for laparoscopic cholecystectomy

Postoperative pain is the most common complaint after laparoscopic cholecystectomy. This study was carried out to evaluate whether preoperative administration of intramuscular dezocine can provide postoperative analgesia and reduce postoperative opioid consumption in patients undergoing laparoscopic cholecystectomy. Patients (ASA I or II) scheduled for laparoscopic cholecystectomy were randomly assigned into intramuscular dezocine group (group 1) or intramuscular normal saline group (group 2). Dezocine and equal volume normal saline were administered intramuscularly 10 min before the induction of anesthesia. After operation, the severity of postoperative pain, postoperative fentanyl requirement, incidence and severity of side-effects were assessed. Postoperative pain and postoperative patient-controlled fentanyl consumption were reduced significantly in group 1 compared with group 2. The incidence and severity of side effects were similar between the two groups. Preoperative single-dose administration of intramuscular dezocine 0.1 mg/kg was effective in reducing postoperative pain and postoperative patient-controlled fentanyl requirement in patients undergoing laparoscopic cholecystectomy.

Opioid antagonist effects of dezocine in opioid-dependent humans

Dezocine is an opioid mu-partial agonist recently approved for use as an analgesic in the United States. This study characterized the relative agonist versus antagonist effects of dezocine in comparison to naloxone (an opioid antagonist), hydromorphone (an opioid mu-agonist), and placebo (saline solution) in opioid-dependent volunteers. In a residential laboratory, six volunteer male opioid abusers maintained on 30 mg/day oral methadone underwent pharmacologic challenges two to three times per week, 20 hours after the last dose of methadone. Challenges consisted of a double-blind intramuscular injection of dezocine (dose range, 7.5 to 60 mg), hydromorphone (5 and 10 mg), naloxone (0.1 and 0.2 mg), or saline solution. Measures included physiologic indexes, self-reports of drug effects, and observer ratings of drug effects. Naloxone and hydromorphone produced characteristic antagonist-like and agonist-like effects, respectively. Dezocine acted as an opioid antagonist, precipitating a withdrawal syndrome only slightly different from that produced by naloxone. Dezocine's antagonist effects were not directly dose related, but peaked at intermediate doses and declined at higher doses.

Single- and multiple-dose pharmacokinetics of dezocine in patients with acute or chronic pain

The pharmacokinetic properties of dezocine were examined in 15 patients with acute or chronic pain. In 3 groups of 5 patients each, serum levels were determined at various intervals after single intravenous doses of 5, 10, and 20 mg. After these single doses, dezocine was very rapidly distributed (mean t1/2 alpha less than 2 minutes), and then rather rapidly eliminated (mean t1/2 beta about 4 hours); the apparent volume of distribution was large (mean Vz beta about 6 L/kg) as was the total clearance (mean CL about 1.5 L/h/kg). In 2 groups of 5 patients each, serum levels were determined after the first and third of 3 intravenous doses of 5 or 20 mg given at 3-hour intervals. The pharmacokinetic parameters after these multiple doses were consistent with those after the single doses. Although some observations were suggestive, there was no unequivocal evidence that the pharmacokinetics were dose-related. In 7 serum samples containing dezocine at concentrations ranging from 12.8 to 522 ng/mL, the mean (+/- SE) proportion of dezocine bound to protein was 91.6 +/- 0.8%.

The opioid receptor binding of dezocine, morphine, fentanyl, butorphanol and nalbuphine

The ability of morphine, fentanyl, butorphanol, nalbuphine, and dezocine to compete with radiolabeled ligands for binding at the mu1, mu2, kappa1, and delta opioid receptors and the sigma receptor was characterized. In the absence of sodium, the potency of opioid receptor competition at each receptor site was found to be: mu1-fentanyl > butorphanol > morphine > or = dezocine = nalbuphine; mu2-butorphanol > fentanyl > nalbuphine > morphine = dezocine; kappa1-butorphanol > nalbuphine >> morphine > or = dezocine > fentanyl; and delta-butorphanol > nalbuphine > or = dezocine > morphine > fentanyl. For all five compounds, competition at the sigma receptor was weak, with nalbuphine and dezocine having Kis of approximately 0.5 microM and the other opioids having Kis of greater than 1 microM. Since the presence of 100 mM NaCl during the competitive binding decreased the K(i), to varying degrees, of all five opioids at the mu1 and delta receptors and of some of the opioids at the mu2 and kappa1 receptors, the five compounds studied appear to differ in efficacy at the five receptor sites.

Opioid agonist-antagonist drugs in acute and chronic pain states

The agonist-antagonist opioid analgesics are a heterogeneous group of drugs with moderate to strong analgesic activity comparable to that of the pure agonist opioids such as codeine and morphine but with a limited effective dose range. The group includes drugs which act as an agonist or partial agonist at one receptor and an antagonist at another (pentazocine, butorphanol, nalbuphine, dezocine) and drugs acting as a partial agonist at a single receptor (buprenorphine). These drugs can be classified as nalorphine-like or morphine-like. Meptazinol does not fit into either classification and occupies a separate category. Pentazocine, butorphanol and nalbuphine are weak mu-antagonists and kappa-partial-agonists. All three drugs are strong analgesics when given by injection: pentazocine is one-sixth to one-third as potent as morphine, nalbuphine is slightly less potent than morphine, and butorphanol is 3.5 to 7 times as potent. The duration of analgesia is similar to that of morphine (3 to 4 hours). Oral pentazocine is closer in analgesic efficacy to aspirin and paracetamol (acetaminophen) than the weak opioid analgesics such as codeine. Neither nalbuphine nor butorphanol is available as an oral formulation. At usual therapeutic doses nalbuphine and butorphanol have respiratory depressant effects equivalent to that of morphine (though the duration of such effects with butorphanol may be longer). Unlike morphine there appears to be a ceiling to both the respiratory depression and the analgesic action. All of these 3 drugs have a lower abuse potential than the pure agonist opioid analgesics such as morphine. However, all have been subject to abuse and misuse, and pentazocine (but not the others) is subject to Controlled Drug restrictions. Buprenorphine is a potent partial agonist at the mu-receptor, and by intramuscular injection is 30 times as potent as morphine. A ceiling to the analgesic effect of buprenorphine has been demonstrated in animals and it is also claimed in humans. However, there are no reliable data available to define the maximal dose of buprenorphine in humans. A practical ceiling exists for sublingual use in that the only available formulation is a 2 micrograms tablet and few patients will accept more than 3 or 4 of these in a single dose. The duration of analgesia is longer than that of morphine, at 6 to 9 hours. There have been suggestions that buprenorphine causes less respiratory depression than morphine, but viewed overall it appears that in equianalgesic doses the 2 drugs have similar respiratory depressant effects.(ABSTRACT TRUNCATED AT 400 WORDS)