Drug Database
FE

fentanyl citrate (OX20 / Rapinyl / EN 3267)

✓ Approved

Kyowa Kirin Co., Ltd. · Small Molecule · Small Molecule

What is fentanyl citrate?

fentanyl citrate is a small molecule developed by Kyowa Kirin Co., Ltd.. It is approved for therapeutic indications via oral (po) or sublingual (sl)/oral transmucosal or topical.

Drug Profile

Brand NamesOX20, Rapinyl, EN 3267
CompanyKyowa Kirin Co., Ltd.
Drug ClassSmall Molecule
RouteOral (PO), Sublingual (SL)/Oral Transmucosal, Topical
StatusApproved
Sources: ClinicalTrials.gov, Kyowa Kirin Co., Ltd.

Therapeutic Indications

fentanyl citrate is developed for 1 unique indication across 1 therapeutic area.

Therapeutic AreaConditionPhase
Neoplasms benign, malignant and unspecified (incl cysts and polyps)Cancer pain✓ Approved

Related Research Articles

PubMedZhonghua nan ke xue = National journal of andrology2026-11-11

[Effect of zinc selenium L-carnitine compound nutrient combined with tamoxifen citrate on routine semen parameters and sperm DNA fragmentation index in male infertility patients].

Xie Yuanzhi Y, Xin Meijiao M, Shi Nanxiang N, Shi Yimin Y et al.

Objective To explore the effect of zinc selenium L-carnitine compound nutrient combined with tamoxifen citrate on routine semen parameters and sperm DNA fragmentation index of male infertility patients with abnormal sperm DNA fragmentation index. Methods A total of 903 male infertile patients with sperm DFI (>15%) were selected and randomly divided into control group (453 cases) and combination group (450 cases). The control group was treated with vitamin E soft capsule, and the combination group was treated with zinc selenium L-carnitine compound nutrient combined with tamoxifen citrate. The percentages of normal morphology sperm, sperm volume, sperm concentration, percentage of forward moving sperm（PR）, percentage of non-forward moving sperm（NP）, and DFI of patients in the two groups were collected before treatment and 1, 2 and 3 months after treatment. The effective rates of combined medication treatment for patients with abnormal DFI in different age groups were compared. Results After 1 month of treatment in the combination group, PR increased significantly and DFI decreased significantly (P<0.01). After 2 months of treatment, compared with before treatment, PR (P<0.01) and NP increased (P<0.05), DFI decreased (P<0.01). After 3 months of treatment, the semen volume increased compared with before treatment (P<0.05), and DFI decreased continuously (P<0.01). However, there was no significant difference in the percentage of normal morphological sperm and sperm concentration compared with before treatment (P>0.05). In the control group, PR increased significantly after 1 and 2 months of treatment compared with before treatment (P<0.01, P<0.05), and DFI decreased significantly (P<0.001, P<0.01). However, there was no statistically significant difference in the percentage of normal morphological sperm, semen volume, sperm concentration, and NP compared with before treatment. There was no significant difference in any parameters after 3 months of treatment compared with before treatment (P>0.05). Before treatment, the differences in various parameters between the two groups were not significant (P>0.05). After 1 and 2 months of treatment, compared with the control group, the DFI of the combination group showed a significant decrease (P<0.01, P<0.05), and the differences in other parameters were not significant (P>0.05). After 3 months of treatment, the differences in various parameters between the two groups were not significant (P>0.05). Among the patients in the combination group with DFI>25%, the treatment effectiveness rate of patients aged ≥35 years was higher than that of those aged <35 years old (P<0.01); while among the patients in the combination group with 15%0.05). Conclusion The zinc selenium L-carnitine compound nutrient combined with tamoxifen citrate can improve PR and sperm DNA integrity of male infertility patients. Meanwhile, patients with higher baseline DFI values combined with older age have better therapeutic effects.

PMID 43012228
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PubMedAnalytical chemistry2026-11-11

96-Sample Parallel BioSPME-DART-MS Platform for Rapid Screening of Fentanyl and its Analogues in Biofluids.

Zhou Wei W, Driezen Marc M, Pawliszyn Janusz J

Solid-phase microextraction (SPME) with biocompatible coating material is highly compatible with ambient mass spectrometry (AMS), such as direct analysis in real time (DART), for improving sensitivity and reducing matrix effects. However, the practical throughput of SPME-DART-MS remains limited by the mismatch between parallel sample preparation and device-to-source transfer. Here, we introduce a 96-sample parallel BioSPME-DART-MS platform that integrates automated SPME extraction, 96-channel liquid transfer, and a matched 96-position DART mesh interface. This design enables 96 biological samples to be processed in a plate-based format, greatly improves workflow transferability. Thin HLB/PAN-coated SPME blades were used to provide bio-compatible extraction and cleanup from whole blood, plasma, and urine. After desorption in 200 μL of solvent, only 5 μL of the extract was transferred to the DART mesh for rapid MS/MS screening, while the remaining solution was retained for sequential LC-MS/MS confirmation without additional sample preparation. The system enabling an average analysis time of approximately 40 s per sample. Using six fentanyl and its analogues as model analytes, the BioSPME-DART-MS method achieved good sensitivity across the three biofluids, with limits of detection of 0.10-0.50 ng mL-1 in whole blood, 0.03-0.20 ng mL-1 in plasma, and 0.01-0.20 ng mL-1 in urine. In addition, a comparative study of absolute matrix effects revealed that chromatography-free DART-MS and blade spray-MS remained susceptible to ion suppression, whereas LC-ESI-MS showed negligible matrix effects. This platform establishes a high-throughput, two-tier SPME-MS workflow that combines rapid ambient MS screening with chromatography-based confirmation.

PMID 43010421
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PubMedBMC veterinary research2026-11-11

Effects of different feeding regimes on growth performance, antioxidant activity, rumen fermentation, rumen microbiota and rumen metabolism in beef cattle.

Lu Qi Q, Zhou Di D, Yang Rong R, Ban Yiming Y et al.

The feeding regime significantly impacts on the production performance, ruminal fluid microbiota, and metabolites of ruminants. However, studies comparing the microbial metagenomics and metabolites in ruminal fluid of beef cattle fed pasture-based grazing and housed total mixed ration (TMR) feeding regimes have rarely been reported. Forty healthy Guanling beef cattle were divided into two equal groups according to a randomized complete block design. The pasture-based grazing group (BG) was allowed to the grazing period was 08:00-18:00 at a natural ranch. The housed TMR feeding group (BB) was reared under a housed feeding system and fed a TMR diet. Each treatment consisted of 20 beef cattle, and the experimental period lasted for 90 d. The metagenomics and metabolomics were used analysis ruminal fluid microbiota and metabolism. The results indicated that the BB group showed significantly higher levels of average daily gain, total antioxidant capacity, catalase, 2,2-diphenyl-1-picrylhydrazyl scavenging activity, ammonia nitrogen, and volatile fatty acid (P < 0.05), whereas it had significantly lower levels of malondialdehyde and hydroxyl free radical relative to the BG group (P < 0.05). Compared with the BB group, the BG group exhibited a significantly increased (P < 0.05) abundance of Bacillota at the phylum level but a significantly decreased (P < 0.05) abundance of Prevotella at the genus level. The modules associated with these relative abundance levels (Reductive citrate cycle (Arnon-Buchanan cycle), and Guanine ribonucleotide degradation, GMP = > Urate) were significantly more important in the BG group (P < 0.05) than in the BB group. Glycosyltransferase 2_Glycos_transf_2 was significantly enriched in the BB group, whereas glycoside hydrolase (GH)3, GH78, and GH36 were significantly enriched in the BG group. Metabolomic analysis revealed that linoleic acid metabolism was the dominant pathway in the rumen. Overall, the housed TMR-fed cattle enhanced growth performance, antioxidant activity, rumen fermentation, and Prevotella abundance, whereas the pasture-based grazing fed cattle enhanced Bacillota abundance and linoleic acid metabolism.

PMID 43009984
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PubMedDrug and alcohol dependence2026-11-10

Fentanyl and xylazine precipitated withdrawal in Swiss Webster mice.

Shepherd Brandon B, Cakir Kerim K, Walker Ellen A EA

In recent years, α2-adrenoreceptor (α2AR) agonists have become common adulterants of illicit fentanyl supplies. One such drug is xylazine, a veterinary anesthetic not approved for human use. There is little known about effects of xylazine upon repeated administration, interactions between fentanyl and xylazine, and how xylazine may alter withdrawal from fentanyl. In this work, we established a precipitated withdrawal procedure with the goal of understanding withdrawal from xylazine and how it may impact withdrawal from fentanyl. Mice received fentanyl, xylazine, or both, followed by antagonists naloxone, idazoxan, or both 2h later. Mice were then placed into a large glass beaker and observed for two 60s intervals at 9- and 17-min post injection, and presence of withdrawal signs was recorded in each interval. Injections of fentanyl or xylazine followed by antagonists naloxone or idazoxan, respectively, each produced a unique set of precipitated withdrawal signs. Both produced significant grimace and wet dog shakes; however, precipitated fentanyl withdrawal also produced paw tremors and jumps whereas xylazine withdrawal produced scratching. Xylazine coadministration with fentanyl increased the frequency of some signs of fentanyl precipitated withdrawal while decreasing others. This work suggests that the addition of xylazine to illicit fentanyl supplies is changing the somatic state of fentanyl withdrawal, which may impact patients in clinical settings.

PMID 43008358
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PubMedBehavioural pharmacology2026-11-10

Fentanyl-induced postural changes across species: behaviors, mechanisms, and translational implications.

Raffa Robert B RB, Phay Monichan H MH, Kwee Lia L, Miller Thomas L TL et al.

This narrative review summarizes fentanyl-induced postural effects across species, focusing on a postulated cerulospinal noradrenergic connection linking rodent catalepsy models to human wooden-chest syndrome (WCS). This could have possible translational relevance for fentanyl overdose and its clinical management. A review of English-language literature was conducted using PubMed and EMBASE. Reference lists of retrieved articles and prior reviews on the topic were searched for additional sources. The evidence supports that fentanyl-induced postural effects are centrally mediated to a significant extent through µ-opioid receptor (MOR) activation in the locus cœruleus, with downstream engagement of cerulospinal noradrenergic projections onto spinal α1-adrenoceptors. Further, this integrated pathway is subject to modulation by nitric oxide and glutamatergic signaling, striatal dopaminergic-medium spiny neuron circuitry, and pontine respiratory nuclei. Phenomenology differs substantially across species, dose, and route of administration, but a phylogenetically conserved MOR-cerulospinal-noradrenergic pathway, modulated by nitric oxide and dopaminergic circuitry, appears to underlie fentanyl-induced postural disturbances across species, from cataleptic immobility in rodents to WCS in humans. The conserved mechanism is expressed as species-specific chest-wall mechanics that are a determinant of clinical severity, and helps to understand the potential role of α2-adrenoceptor agonists as being mechanistically rational for overdose management.

PMID 43006687
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PubMedRSC medicinal chemistry2026-11-10

Development of novel Mu opioid receptor antagonists based on a 6,4-spiro bicyclic fentanyl-derived scaffold.

Li Ennian E, Neel Logan T LT, Upadhyay Neha N, Reda Ahmed A et al.

Scaffold reorganization represents a strategy for modulating Mu opioid receptor (MOR) signaling within flexible opioid scaffolds. Herein, a 6,4-spiro bicyclic core derived from the fentanyl framework was adopted to reduce conformational flexibility while preserving key pharmacophoric features of the parent 8-membered scaffold. Biological evaluations identified compound 3, bearing 2-furanyl and cyclobutylmethyl substituents, as the most potent analogue in this series. Compound 3 exhibited MOR binding affinity (K i = 25 nM), and antagonist-like activity in vivo against morphine- and fentanyl-induced antinociception while displaying minimal intrinsic efficacy (E max = 3% of DAMGO) in functional assays. Compound 3 also showed excellent metabolic stability in human liver S9 fractions, reduced CNS exposure relative to naltrexone, and no measurable respiratory depression at the tested dose. Conformational analysis and molecular docking suggest that the 6,4-spiro scaffold preserves MOR binding while limiting accessible ligand conformations, supporting scaffold reorganization as a strategy to finetune MOR efficacy through fentanyl-derived scaffolds.

PMID 43005752
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