Nalbuphine attenuates morphine-induced scratching by inhibiting PKCß-dependent microglial activation and p38 phosphorylation in male mice.

Morphine-induced scratching (MIS) is a common adverse effect associated with the use of morphine as analgesia after surgery. However, the treatment of MIS is less than satisfactory due to its unclear mechanism, which needs to be enunciated. We found that intrathecal (i.t.) injections of morphine significantly enhanced scratching behavior in C57BL/6J male mice as well as increased the expressions of protein kinase C ß (PKCß), phosphorylated p38 mitogen-activated protein kinases (MAPK), and ionized calcium-binding adapter molecule 1 (Iba1) within spinal cord dorsal horn. Conversely, using the kappa opioid receptor antagonist nalbuphine significantly attenuated scratching behavior, reduced PKCß expression and p38 phosphorylation, and decreased spinal dorsal horn microglial activation, while PKCδ and KOR expression elevated. Spinal PKCß silencing mitigated MIS and microglial activation. Still, knockdown of PKCδ reversed the inhibitory effect of nalbuphine on MIS and microglial activation, indicating that PKCδ is indispensable for the antipruritic effects of nalbuphine. In contrast, PKCß is crucial for inducing microglial activation in MIS in male mice. Our findings show a distinct itch cascade of morphine, PKCß/p38MAPK, and microglial activation, but an anti-MIS pathway of nalbuphine, PKCδ/KOR, and neuron activation.

Nalbuphine Suppresses Leukemia Stem Cells and Acts Synergistically with Chemotherapy Drugs via Inhibiting Ras/Raf/Mek/Erk Pathway.

AIMS: Retrospective clinical studies have shown that opioids could potentially affect the risk of cancer recurrence and metastasis. Better understanding of the effects of opioids on cancer will help to select the optimal anesthetic regimens to achieve better outcomes in cancer patients. BACKGROUND: Increasing evidence has shown the direct effects of opioids on bulk cancer cells and cancer stem cells. Opioid such as nalbuphine is approved to control cancer-associated pain but little is known on their possible cancer effects. OBJECTIVE: To assess the biological effects of nalbuphine on acute myeloid leukemia (AML) differentiated and stem/progenitor CD34+ cells. METHODS: AML CD34+ cells were isolated with colony formation, growth and apoptosis assays performed. Biochemical and immunoblotting analyses were conducted in AML cells exposed to nalbuphine. RESULTS: Nalbuphine at clinically relevant concentrations was active against a panel of AML cell lines with varying IC50. Importantly, nalbuphine augmented the efficacy of cytarabine and daunorubicin in decreasing AML cell viability/ growth. Besides bulk AML cells, we noted that nalbuphine was effective and selective in decreasing viability and colony formation of AML CD34+ cells while sparing normal hematopoietic CD34+ cells. The action of nalbuphine on AML cells is not associated with opioid receptors but via inhibiting Ras/Raf/MEK/ERK signaling pathway. Overexpression of constitutively active Ras partially but significantly reversed the inhibitory effects of nalbuphine on AML cells. CONCLUSION: Our findings reveal the selective anti-AML activity of nalbuphine and its ability in inhibiting Ras signaling. Our work suggests that nalbuphine may be beneficial for leukemia patients.

Interaction of nalbuphine hydrochloride with deoxyribonucleic acid measured by fluorescence quenching.

The interaction of nalbuphine hydrochloride with calf thymus deoxyribonucleic acid was investigated by absorption and fluorescence titration techniques. Hypochromic effect was observed in the absorption spectra of nalbuphine. The fluorescence quenching of nalbuphine by DNA was found to be static according to Stern-Volmer constant at different temperature (2.257×103 L/mol and 1.678×103 L/mol at 298 K and 308 K respectively; binding constants (K) between calf thymus DNA and nalbuphine were 2.081×103 and 8.26×101 at 298 K and 308 K respectively). The binding numbers (n) were 0.9955 and 0.6762 with the standard deviation of 0.225 at 2 different temperatures which indicates mol ratio of Nalbuphine and DNA remains unchanged at different temperatures (298 K and 308 K). The binding affinity of nalbuphine to DNA was calculated at different temperatures and the stoichiometry of binding was characterized to be about 1 nalbuphine molecule per nucleotide. Calibration for nalbuphine, based on quenching titration data, was linear in the concentration range 6.3×10-6 to 6.4×10-4 mol/L. And these binding forces also indicate the binding site of Nalbuphine to be at the minor groove of DNA.

Excretion of ketoprofen and nalbuphine in human milk during treatment of maternal pain after delivery.

Analgesics are required to prevent and treat postpartum pain, but breast-feeding may be contraindicated, because data on milk transfer are very limited. The present study was undertaken to quantify the transfer of ketoprofen and nalbuphine in milk. Eighteen patients gave their informed consent to participate and completed the study. Following delivery, they received ketoprofen (100 mg/12 hours) and nalbuphine (0.2 mg/kg/4 hours) as an intravenous bolus over 2 to 3 days for postpartum pain. Milk samples were collected during the 12 hours between the third and fourth ketoprofen administrations. Ketoprofen and nalbuphine concentrations were determined with high-performance liquid chromatography. The mean and maximum ketoprofen milk concentrations were 57+/-37 and 91+/-51 ng/mL, respectively. Assuming a milk volume of 150 mL/kg/day, the mean and maximum doses that a breast-fed neonate would ingest during one day are 8.5+/-5.5 and 13.6+/-7.6 microg/kg/day, respectively, and the relative infant dose is 0.31+/-0.17% of the weight-adjusted maternal daily dose. The mean and maximum nalbuphine milk concentrations were 42+/-26 and 61+/-26 ng/mL, respectively. Assuming a milk volume of 150 mL/kg/day, the mean and maximum doses that a breast-fed neonate would ingest during one day is 7.0+/-3.2 and 9.0+/-3.8 microg/kg/day, and the relative infant dose is 0.59+/-0.27% of the weight-adjusted maternal daily dose. Therefore, breast-feeding is permissible when ketoprofen and/or nalbuphine are administered to the mother to treat postpartum pain.

Hair analysis by LC-MS as evidence of nalbuphine abuse by a nurse.

Individuals in any profession can succumb to chemical abuse. Among the healthcare profession, nurses represent a specific group because of their ease of access to drugs, particularly narcotics. Opioids, potentially highly addictive agents, are usually their drug of choice. Nalbuphine, a synthetic opioid analgesic, is prescribed for moderate-to-severe acute pain, for chronic pain syndromes, and in obstetrics to decrease the adverse respiratory effect of opioid epidural administration. The case of a nurse who was suspected of drug misuse after the disappearance of two nalbuphine ampules in an obstetrics service is described. Because of discrepancies in the results of her blood and urine samples, a sample of head hair was subsequently collected from the nurse. A hair analysis of nalbuphine by liquid chromatography-mass spectrometry has not been previously described. Following decontamination and grinding, hair was mixed with a Söerensen buffer, then subjected to ultrasonic treatment (1 h), and extracted with ethyl acetate. A quantitative analysis was performed with two channels (30 and 45 V), and it is based on a m/z 358 for nalbuphine and a m/z 330 for methylclonazepam as an internal standard. The method was linear from 0.020 to 12 ng/mg of hair (R(2) = 0.972), and the limit of detection and limit of quantitation are 0.020 ng/mg. Accuracy (CV), assessed at 0.4 and 1.6 ng/mg of hair, was 6.18% and 5.77%, respectively, for intraday assays and 4.5% and 10.9% for interday assays. Recovery efficiency at 1.6 ng/mg and 8 ng/mg of hair was 100% and 97.4%, respectively. The hair specimen from the nurse (6 cm) was cut into three equal lengths. Nalbuphine, venlafaxine, and nordiazepam were detected. The concentration of nalbuphine was similar in the three hair locks: 5.07, 7.06, and 5.70 ng/mg of hair. A hair analysis revealed the repeated intake of nalbuphine by the nurse. This person was treated for depression for several months with Effexor (venlafaxine) and Nordaz (nordiazepam) prior to the investigation. Hair appears to be a unique matrix to provide evidence for chronic drug exposure by establishing a historic record that is not possible by blood or urine analysis.

Membrane microviscosity modulates mu-opioid receptor conformational transitions and agonist efficacy.

The influence of membrane microviscosity on mu-opioid agonist and antagonist binding, as well as agonist efficacy, was examined in membranes prepared from SH-SY5Y cells and from a C6 glioma cell line stably expressing the rat mu-opioid receptor (C6mu). Addition of cholesteryl hemisuccinate (CHS) to cell membranes increased membrane microviscosity and reduced the inhibitory effect of sodium and guanine nucleotides on the affinity of the full agonists sufentanil and [D-Ala2,N-MePhe4,Gly-ol5]enkephalin (DAMGO) for the mu-opioid receptor. Binding of the antagonists [3H]naltrexone and [3H]diprenorphine and the partial agonist nalbuphine was unaffected by CHS. The effect of CHS on agonist binding was reversed by subsequent addition of cis-vaccenic acid, suggesting that the effect of CHS is the result of increased membrane microviscosity and not a specific sterol-receptor interaction. CHS addition increased the potency of DAMGO to stimulate guanosine-5'-O-(3-[35S]thio)triphosphate binding by fourfold, whereas the potency of nalbuphine was unaffected. However, nalbuphine efficacy relative to that of the full agonist DAMGO was strongly increased in CHS-treated membranes compared with that in control membranes. Membrane rigidification also resulted in an increased efficacy for the partial agonists meperidine, profadol, and butorphanol relative to that of DAMGO as measured by agonist-stimulated GTPase activity in control and CHS-modified membranes. These findings support a regulatory role for membrane microviscosity in receptor-mediated G protein activation.

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.

Species variation in the disposition of nalbuphine and its acetylsalicylate ester analogue.

1. The disposition of (-)17-(cyclobutylmethyl)-4,5 alpha-epoxymorphinan-3,6 alpha, 14-triol (Nalbuphine, Nubain) and its 3-acetylsalicylate ester has been studied in rat and dog to determine whether this analogue can improve the oral bioavailability of nalbuphine. 2. In dog, administration of the acetylsalicylate analogue increased nalbuphine bioavailability 5-fold to 16% and this correlated with an increase in analgesic activity. 3. The disposition of the analogue in rat was characterized by low oral bioavailability and a short plasma half-life. 4. Although nalbuphine acetylsalicylate was rapidly hydrolysed to nalbuphine in rat, nalbuphine bioavailability was not increased in this species. 5. Other studies have shown that these conflicting results are due to species differences in nalbuphine metabolism. Conjugation at the 3-hydroxyl position is the major metabolic pathway for nalbuphine in dog but not rat. Consequently, 3-hydroxyl esters are ineffective prodrugs for nalbuphine in rat and probably man.

Nalbuphine: an autoradiographic opioid receptor binding profile in the central nervous system of an agonist/antagonist analgesic.

Nalbuphine is a potent agonist/antagonist analgesic with a low side effect profile and low abuse potential. Previous studies have shown that nalbuphine produces predominantly agonist (analgesic) effects at kappa receptors and antagonist (morphine-reversal) effects at mu receptors in vivo. The present study was designed to localize the sites of nalbuphine binding to mu, delta and kappa opioid receptors in the central nervous system (CNS) using in vitro labeling light microscopic autoradiography. Mu, delta and kappa opioid receptors were labeled selectively using [3H]dihydromorphine, D-[3H]Ala2-D-Leu5-enkephalin and (-)-[3H]ethylketocyclazocine, respectively. In displacement studies in rat brain homogenates, nalbuphine had the highest affinity (Ki) for mu receptors (0.5 nM) with progressively lower affinities for kappa (29 nM) and delta (60 nM) opioid receptors. In autoradiographic studies in slide-mounted sections of guinea pig brain and monkey spinal cord, nalbuphine (300 nM) displaced completely the binding at mu and kappa receptors without significantly altering the binding at delta receptors. The binding of [3H]nalbuphine in slide-mounted sections of guinea pig forebrain was saturable and showed a curvilinear profile indicating the presence of two binding sites with apparent dissociation constant (Kd) values of 0.5 and 12 nM. Morphine and U-50,488H, which have high affinities for mu and kappa opioid receptors, respectively, inhibited [3H]nalbuphine binding with IC50 values of 0.9 and 10 nM, respectively. In saturation studies, morphine (50 nM) and U-50,488H (100 nM) selectively blocked the high and low affinity components of [3H]nalbuphine binding, respectively. The autoradiographic distribution of [3H]nalbuphine binding sites in the CNS corresponds well to the distribution of mu and kappa opioid receptors. In addition, CNS areas (deep layers of the cerebral cortex, laminae I and II of the spinal cord, substantia gelatinosa of the trigeminal nerve, periaqueductal gray and thalamic nuclei) that mediate analgesia contain high concentrations of [3H]nalbuphine binding sites. In summary, these data demonstrate that nalbuphine acts on mu and kappa opioid receptors and identify anatomical loci in the CNS in which nalbuphine may produce its actions.

Disposition of nalbuphine in patients undergoing general anaesthesia.

The pharmacokinetics of nalbuphine 20 mg i.v. were studied in 10 patients undergoing lower abdominal or body surface surgery. Blood sampling was carried out for 600 min after injection and drug concentrations were measured by HPLC using electrochemical detection. Disposition was best described as a triexponential function, with a mean elimination half-life of 135.5 min. Mean residence time, clearance, and volumes of distribution, Vss and V beta, were determined by a model independent method, and gave mean values of 149.7 min (MRT), 1095 ml min-1 (ClP), 159.9 litre (Vss) and 207.1 litre (V beta).

Sinusoidal fetal heart rate pattern after administration of nalbuphine hydrochloride: a case report.

Nalbuphine hydrochloride (Nubain) is a synthetic analgesic available for use during labor. It is known to possibly cause respiratory depression in the neonate, but to date there are no published reports of any intrapartum alterations of fetal heart rate. A case presentation is given of a persistent sinusoidal pattern appearing after Nubain administration.

Opioids with different affinity for subreceptors induce different effects on early and late sensory evoked potentials (SEP) in man.

Amplitude changes of event-related sensory potentials (SEP's) present objective measurements for the evaluation of pain perception in man. Alfentanil, an opioid with dominant binding to the mu-receptor was given in graded doses (5-, 10- micrograms/kg) to volunteers. Nalbuphine, an opioid with reported kappa-agonist activity, was given in graded doses (100-, 500-, 1000- micrograms/kg) to another group i.v. Both groups were also exposed to progressively increased electrical stimulations (mA) in order to determine tolerance threshold before and after drug administration. In the alfentanil group (n = 5) there was a dose- related decrease of the amplitude of the early N20-peak. The late N100-peak was not, however, affected. This correlated closely (r = 0.87) with a naloxone-reversible increase of tolerance to electrical current. In the nalbuphine group (n = 15), there was a dose-related, naloxone non-reversible reduction of amplitude of the late N100-peak which showed a good correlation (r = 0.9) with an increase in current threshold. As the early evoked potentials are primarily generated in the pontine-thalamic region, it is suggested that the mode of action of alfentanil resembles that of a blockade of sensory impulses. The latter takes place before impulses are transmitted to more rostrally located CNS structures which are responsible for pain identification. The late evoked potential affected by nalbuphine indicates an activity on thalamo-cortical projection sites which are involved in subjects' cognitive activities. Kappa-ligands, therefore, seem to exert a different mode of action than mu-opioids, which results in a modulation of the negative emotional response associated with pain, rather than an attenuation of pain impulses.

Oral and rectal nalbuphine bioavailability: first-pass metabolism in rats and dogs.

The disposition of the narcotic antagonist/analgesic nalbuphine after i.v., oral, and rectal dosing was evaluated in rats and dogs. In both species nalbuphine had high systemic clearance and low oral bioavailability as a result of extensive first-pass metabolism. Administration to a closed 2 cm length of rectum in rats resulted in complete bioavailability; first-pass metabolism was circumvented. However, the extent of first-pass metabolism increased when the dose was not restricted to the lower rectum. Rectal nalbuphine bioavailability in dogs from a solution or three suppository formulations was low and equivalent to oral bioavailability. This was probably because of upward spreading of the dose and subsequent first-pass metabolism. Sodium salicylate, which has been shown to improve rectal absorption of other drugs, did not affect nalbuphine bioavailability rectally.

Butorphanol and nalbuphine: a pharmacologic comparison.

The agonist/antagonist analgesics, butorphanol (Stadol) and nalbuphine (Nubain), are being increasingly employed as intravenous sedation agents; nalbuphine will be available in the future as an oral analgesic. The drugs possess numerous pharmacologic similarities and some dissimilarities. Both are equianalgesic (and nalbuphine is equipotent) with morphine parenterally and codeine orally. Their pharmacokinetics are similar; nalbuphine has a longer duration of action. Both may precipitate an abstinence syndrome in narcotic-dependent persons and will probably be associated with low-level drug abuse potential. They are both agonists of the kappa opioid receptor and partial agonists of the mu receptor. Butorphanol is a partial agonist of the sigma receptor responsible for psychotomimetic effects. The incidence of adverse effects is low, sedation being the most common. In cardiac-risk patients, nalbuphine does not increase cardiac work or oxygen requirements; nor do increasing doses of nalbuphine increase the duration of respiratory depression. Both drugs possess plateau respiratory depressant actions.

Nalbuphine. A preliminary review of its pharmacological properties and therapeutic efficacy.

Nalbuphine is an agonist/antagonist analgesic. After parenteral administration of 'usual' doses it is approximately equipotent in analgesic activity to morphine on a weight basis. In studies in patients with moderate to severe pain, usually following surgery, the characteristics of analgesia with nalbuphine were comparable to those seen with equianalgesic doses of morphine or pentazocine. It also appears to produce satisfactory anaesthesia when used as a component of a 'balanced' anaesthesia technique, although a relatively low 'ceiling' effect for reduction of anaesthetic requirements with nalbuphine may limit its usefulness in this regard. As with other agonist/antagonist analgesics, a 'ceiling' effect to nalbuphine-induced respiratory depression is also seen, beyond which further depression does not readily occur. However, with usual analgesic doses, respiratory depression seen with nalbuphine is comparable to that with morphine. Important haemodynamic changes have not occurred after usual doses of nalbuphine, even in patients with cardiac disease. Like other agonist/antagonist analgesic drugs, the abuse potential of nalbuphine seems relatively low, but only wider clinical use for longer periods can establish this with certainty. Thus, nalbuphine appears to offer a useful alternative to morphine in patients with moderate to severe pain.