-
Therapeutic Advances in... 2024This case report examines the possible correlation between the clozapine/norclozapine ratio and the occurrence of constipation and paralytic ileus. We present the case...
This case report examines the possible correlation between the clozapine/norclozapine ratio and the occurrence of constipation and paralytic ileus. We present the case of a 42-year-old patient diagnosed with schizoaffective disorder undergoing clozapine therapy. Despite intensive treatment with clozapine, haloperidol, valproic acid and biweekly electroconvulsive therapy sessions for over a year, florid psychotic symptoms and fluctuating mood swings persisted. Therefore, valproic acid was replaced by carbamazepine, a potent inducer of several CYP450-enzymes. To maintain clozapine plasma levels, fluvoxamine, a CYP1A2-inhibitor, was introduced at a dose of 25 mg before this switch. After addition of carbamazepine, there was a significant decline in clozapine levels, necessitating an increase in fluvoxamine dosage to 50 mg. Five weeks later the patient was admitted to a general hospital with a diagnosis of paralytic ileus. Treatment with enemas proved effective. Drug concentration analysis revealed a 2.5-fold increase in norclozapine levels in the weeks preceding hospital admission, resulting in an inverted clozapine/norclozapine ratio. Treatment with clozapine, carbamazepine and fluvoxamine was continued as the patient demonstrated clinical improvement on carbamazepine. Concurrently, an intensive laxative regimen was initiated. Two weeks later, the patient was readmitted to the general hospital due to suspected paralytic ileus and faecal vomiting, once again displaying an inverted clozapine/norclozapine ratio. We discuss potential mechanisms contributing to the occurrence of the paralytic ileus in this patient, including the antagonism of muscarinic M3 receptors by both clozapine and norclozapine, as well as the agonism of delta-opioid receptors by norclozapine. This case highlights the potential significance of both the clozapine/norclozapine ratio and absolute norclozapine levels as risk factors for constipation and paralytic ileus in patients on clozapine therapy.
PubMed: 38827014
DOI: 10.1177/20451253241255487 -
The Pharmacogenomics Journal Jun 2024The aim was to determine if opioid neuroimmunopharmacology pathway gene polymorphisms alter serum morphine, morphine-3-glucuronide and morphine-6-glucuronide...
The aim was to determine if opioid neuroimmunopharmacology pathway gene polymorphisms alter serum morphine, morphine-3-glucuronide and morphine-6-glucuronide concentration-response relationships in 506 cancer patients receiving controlled-release oral morphine. Morphine-3-glucuronide concentrations (standardised to 11 h post-dose) were higher in patients without pain control (median (interquartile range) 1.2 (0.7-2.3) versus 1.0 (0.5-1.9) μM, P = 0.006), whereas morphine concentrations were higher in patients with cognitive dysfunction (40 (20-81) versus 29 (14-60) nM, P = 0.02). TLR2 rs3804100 variant carriers had reduced odds (adjusted odds ratio (95% confidence interval) 0.42 (0.22-0.82), P = 0.01) of opioid adverse events. IL2 rs2069762 G/G (0.20 (0.06-0.52)), BDNF rs6265 A/A (0.15 (0.02-0.63)) and IL6R rs8192284 carrier (0.55 (0.34-0.90)) genotypes had decreased, and IL6 rs10499563 C/C increased (3.3 (1.2-9.3)), odds of sickness response (P ≤ 0.02). The study has limitations in heterogeneity in doses, sampling times and diagnoses but still suggests that pharmacokinetics and immune genetics co-contribute to morphine pain control and adverse effects in cancer patients.
Topics: Humans; Morphine; Male; Female; Cancer Pain; Middle Aged; Analgesics, Opioid; Delayed-Action Preparations; Aged; Pharmacogenetics; Polymorphism, Single Nucleotide; Morphine Derivatives; Adult; Pharmacogenomic Variants; Toll-Like Receptor 2
PubMed: 38824169
DOI: 10.1038/s41397-024-00339-w -
Pharmacological Research Jul 2024Targeting the CCL2/CCR2 chemokine axis has been shown to be effective at relieving pain in rodent models of inflammatory and neuropathic pain, therefore representing a...
Targeting the CCL2/CCR2 chemokine axis has been shown to be effective at relieving pain in rodent models of inflammatory and neuropathic pain, therefore representing a promising avenue for the development of non-opioid analgesics. However, clinical trials targeting this receptor for inflammatory conditions and painful neuropathies have failed to meet expectations and have all been discontinued due to lack of efficacy. To overcome the poor selectivity of CCR2 chemokine receptor antagonists, we generated and characterized the function of intracellular cell-penetrating allosteric modulators targeting CCR2, namely pepducins. In vivo, chronic intrathecal administration of the CCR2-selective pepducin PP101 was effective in alleviating neuropathic and bone cancer pain. In the setting of bone metastases, we found that T cells infiltrate dorsal root ganglia (DRG) and induce long-lasting pain hypersensitivity. By acting on CCR2-expressing DRG neurons, PP101 attenuated the altered phenotype of sensory neurons as well as the neuroinflammatory milieu of DRGs, and reduced bone cancer pain by blocking CD4 and CD8 T cell infiltration. Notably, PP101 demonstrated its efficacy in targeting the neuropathic component of bone cancer pain, as evidenced by its anti-nociceptive effects in a model of chronic constriction injury of the sciatic nerve. Importantly, PP101-induced reduction of CCR2 signaling in DRGs did not result in deleterious tumor progression or adverse behavioral effects. Thus, targeting neuroimmune crosstalk through allosteric inhibition of CCR2 could represent an effective and safe avenue for the management of chronic pain.
Topics: Animals; Receptors, CCR2; Chronic Pain; Ganglia, Spinal; Neuralgia; Humans; Cancer Pain; Bone Neoplasms; Analgesics; Male; Mice; Female; Mice, Inbred C57BL
PubMed: 38823470
DOI: 10.1016/j.phrs.2024.107242 -
Neurobiology of Disease Aug 2024Opioid system dysregulation in response to stress is known to lead to psychiatric disorders including major depression. Among three different types of opioid receptors,...
Opioid system dysregulation in response to stress is known to lead to psychiatric disorders including major depression. Among three different types of opioid receptors, the mu-type receptors (mORs) are highly expressed in the habenula complex, however, the action of mORs in this area and its interaction with stress exposure is largely unknown. Therefore, we investigated the roles of mORs in the habenula using male rats of an acute learned helplessness (aLH) model. First, we found that mOR activation decreased both excitatory and inhibitory synaptic transmission onto the lateral habenula (LHb). Intriguingly, this mOR-induced synaptic depression was reduced in an animal model of depression compared to that of controls. In naïve animals, we found an unexpected interaction between mORs and the endocannabinoid (eCB) signaling occurring in the LHb, which mediates presynaptic alteration occurring with mOR activation. However, we did not observe presynaptic alteration by mOR activation after stress exposure. Moreover, selective mOR activation in the habenula before, but not after, stress exposure effectively reduced helpless behaviors compared to aLH animals. Our observations are consistent with clinical reports suggesting the involvement of mOR signaling in depression, and additionally reveal a critical time window of mOR action in the habenula for ameliorating helplessness symptoms.
Topics: Animals; Habenula; Male; Receptors, Opioid, mu; Helplessness, Learned; Synaptic Transmission; Rats; Depression; Rats, Sprague-Dawley; Stress, Psychological; Disease Models, Animal
PubMed: 38821376
DOI: 10.1016/j.nbd.2024.106543 -
Drugs & Aging Jun 2024Most drugs have not been evaluated in the older population. Recognizing physiological alterations associated with changes in drug disposition and with the ultimate... (Review)
Review
Most drugs have not been evaluated in the older population. Recognizing physiological alterations associated with changes in drug disposition and with the ultimate effect, especially in central nervous system-acting drugs, is fundamental. While considering pharmacokinetics, it should be noted that the absorption of most drugs from the gastrointestinal tract does not change in advanced age. There are only few data about the effect of age on the transdermal absorption of medications such as fentanyl. Absorption from an intramuscular injection may be similar in older adults as in younger patients. The distribution of lipophilic drugs (such as diazepam) is increased owing to a relative increase in the percentage of body fat, causing drug accumulation and prolonged drug elimination following cessation. Phase I drug biotransformation is variably decreased in aging, impacting elimination, and hepatic drug clearance has been shown to decrease in older individuals by 10-40% for most drugs studied. Lower doses of phenothiazines, butyrophenones, atypical antipsychotics, antidepressants (citalopram, mirtazapine, and tricyclic antidepressants), and benzodiazepines (such as diazepam) achieve the same extent of exposure. For renally cleared drugs with no prior metabolism (such as gabapentin), the glomerular filtration rate appropriately estimates drug clearance. Important pharmacodynamic changes in older adults include an increased sedative effect of benzodiazepines at a given drug exposure, and a higher sensitivity to mu opiate receptor agonists and to opioid adverse effects. Artificial intelligence, physiologically based pharmacokinetic modeling and simulation, and concentration-effect modeling enabling a differentiation between the pharmacokinetic and the pharmacodynamic effects of aging might help to close some of the gaps in knowledge.
Topics: Humans; Aged; Central Nervous System Agents; Aging
PubMed: 38814377
DOI: 10.1007/s40266-024-01117-w -
Journal of Medicinal Chemistry Jun 2024Despite the availability of numerous pain medications, the current array of Food and Drug Administration-approved options falls short in adequately addressing pain...
Despite the availability of numerous pain medications, the current array of Food and Drug Administration-approved options falls short in adequately addressing pain states for numerous patients and consequently worsens the opioid crisis. Thus, it is imperative for basic research to develop novel and nonaddictive pain medications. Toward addressing this clinical goal, nalfurafine (NLF) was chosen as a lead and its structure-activity relationship (SAR) systematically studied through design, syntheses, and characterization of 24 analogues. Two analogues, and , showed longer durations of action than NLF in a warm-water tail immersion assay, produced effects primarily mediated by KOR and DOR, penetrated the blood-brain barrier, and did not function as reinforcers. Additionally, produced fewer sedative effects than NLF. Taken together, these results aid the understanding of NLF SAR and provide insights for future endeavors in developing novel nonaddictive therapeutics to treat pain.
Topics: Structure-Activity Relationship; Spiro Compounds; Animals; Morphinans; Mice; Male; Humans; Receptors, Opioid, kappa; Pain Management; Pain; Analgesics
PubMed: 38814086
DOI: 10.1021/acs.jmedchem.4c00646 -
PloS One 2024The vertebrate enteric nervous system (ENS) is a crucial network of enteric neurons and glia resident within the entire gastrointestinal tract (GI). Overseeing essential...
The vertebrate enteric nervous system (ENS) is a crucial network of enteric neurons and glia resident within the entire gastrointestinal tract (GI). Overseeing essential GI functions such as gut motility and water balance, the ENS serves as a pivotal bidirectional link in the gut-brain axis. During early development, the ENS is primarily derived from enteric neural crest cells (ENCCs). Disruptions to ENCC development, as seen in conditions like Hirschsprung disease (HSCR), lead to the absence of ENS in the GI, particularly in the colon. In this study, using zebrafish, we devised an in vivo F0 CRISPR-based screen employing a robust, rapid pipeline integrating single-cell RNA sequencing, CRISPR reverse genetics, and high-content imaging. Our findings unveil various genes, including those encoding opioid receptors, as possible regulators of ENS establishment. In addition, we present evidence that suggests opioid receptor involvement in the neurochemical coding of the larval ENS. In summary, our work presents a novel, efficient CRISPR screen targeting ENS development, facilitating the discovery of previously unknown genes, and increasing knowledge of nervous system construction.
Topics: Animals; Enteric Nervous System; Zebrafish; CRISPR-Cas Systems; Zebrafish Proteins; Neural Crest; Hirschsprung Disease
PubMed: 38809858
DOI: 10.1371/journal.pone.0303914 -
Journal of Medicinal Chemistry Jun 2024Development of more efficacious medications with improved safety profiles to manage and treat multiple forms of pain is a critical element of healthcare. To this end, we...
Development of more efficacious medications with improved safety profiles to manage and treat multiple forms of pain is a critical element of healthcare. To this end, we have designed and synthesized a novel class of tetracyclic pyridopyrroloquinoxalinone derivatives with analgesic properties. The receptor binding profiles and analgesic properties of these tetracyclic compounds were studied. Systematic optimizations of this novel scaffold culminated in the discovery of the clinical candidate, (6,10)-8-[3-(4-fluorophenoxy)propyl]-6,7,8,9,10,10-hexahydro-1-pyrido[3',4':4,5]pyrrolo[1,2,3-]quinoxalin-2(3)-one (compound , ITI-333), which exhibited potent binding affinity to serotonin 5-HT ( = 8.3 nM) and μ-opioid receptors (MOR, = 11 nM) and moderate affinity to adrenergic α ( = 28 nM) and dopamine D ( = 50 nM) receptors. ITI-333 acts as a 5-HT receptor antagonist, a MOR partial agonist, and an adrenergic α receptor antagonist. ITI-333 exhibited dose-dependent analgesic effects in rodent models of acute pain. Currently, this investigational new drug is in phase I clinical development.
Topics: Animals; Humans; Analgesics; Structure-Activity Relationship; Administration, Oral; Pain; Mice; Male; Rats; Drug Discovery; Rats, Sprague-Dawley; Biological Availability; Receptors, Opioid, mu; Pyridines; Pyrroles
PubMed: 38805667
DOI: 10.1021/acs.jmedchem.4c00480 -
Pharmacy (Basel, Switzerland) May 2024Buprenorphine is a semi-synthetic long-acting partial µ-opioid receptor (MOR) agonist that can be used for chronic pain as a sublingual tablet, transdermal patch...
Buprenorphine is a semi-synthetic long-acting partial µ-opioid receptor (MOR) agonist that can be used for chronic pain as a sublingual tablet, transdermal patch (Butrans), or a buccal film (Belbuca). Buprenorphine's unique high receptor binding affinity and slow dissociation at the MOR allow for effective analgesia while offering less adverse effects compared to a full agonist opioid, in particular, less concern for respiratory depression and constipation. It is underused in chronic pain and palliative care due to misconceptions and stigma from its use in opioid use disorder (OUD). This case report discusses the unique pharmacology of buprenorphine, including its advantages, disadvantages, available formulations, drug-drug interactions, initiation and conversion strategies, and identifies ideal populations for use, especially within the palliative care patient population.
PubMed: 38804470
DOI: 10.3390/pharmacy12030078 -
Cell Death Discovery May 2024Despite the success in treating newly diagnosed pediatric acute lymphoblastic leukemia (aLL), the long-term cure rate for the 20% of children who relapse is poor, making...
Despite the success in treating newly diagnosed pediatric acute lymphoblastic leukemia (aLL), the long-term cure rate for the 20% of children who relapse is poor, making relapsed aLL the primary cause of cancer death in children. By unbiased genome-wide retroviral RNAi screening and knockdown studies, we previously discovered opioid receptor mu 1 (OPRM1) as a new aLL cell resistance biomarker for the aLL chemotherapeutic drug, L-asparaginase, i.e., OPRM1 loss triggers L-asparaginase resistance. Indeed, aLL cell OPRM1 level is inversely proportional to L-asparaginase IC50: the lower the OPRM1 level, the higher the L-asparaginase IC50, indicating that aLL cells expressing reduced OPRM1 levels show resistance to L-asparaginase. In the current study, we utilized OPRM1-expressing and -knockdown aLL cells as well as relapsed patient aLL cells to identify candidate targeted therapy for L-asparaginase-resistant aLL. In OPRM1-expressing cells, L-asparaginase induces apoptosis via a cascade of events that include OPRM1-mediated decline in [cAMP], downregulation of PKA-mediated BAD S phosphorylation that can be reversed by 8-CPT-cAMP, cyt C release from the mitochondria, and subsequent caspase activation and PARP1 cleavage. The critical role of PKA inhibition due to a decrease in [cAMP] in this apoptotic process is evident in the killing of OPRM1-knockdown and low OPRM1-expressing relapsed patient aLL cells by the PKA inhibitors, H89 and 14-22 amide. These findings demonstrate for the first time that PKA can be targeted to kill aLL cells resistant to L-asparaginase due to OPRM1 loss, and that H89 and 14-22 amide may be utilized to destroy L-asparaginase-resistant patient aLL cells.
PubMed: 38802344
DOI: 10.1038/s41420-024-02028-w