Lafutidine facilitates calcitonin gene-related peptide (CGRP) nerve-mediated vasodilation via vanilloid-1 receptors in rat mesenteric resistance arteries

Research progress of non-steroidal anti-inflammatory drug-induced small intestinal injury

Non-steroidal anti-inflammatory drugs (NSAIDs) are used widely around the world because of their anti-inflammatory, analgesic, and antiplatelet activity. However, long-term application of NSAIDs can lead to complications. Previously, the clinical attention was dedicated to the NSAID-induced upper gastrointestinal complications. Recently, the detection rate of small intestinal damage related to NSAIDs has increased due to the wide use of endoscopes such as capsule endoscopy and double-balloon colonoscopy. Although the majority of patients have no significant symptoms, there are still a small percentage of patients who develop obvious symptoms or complicated ulcers that require therapeutic intervention. Despite significant advances in our understanding of NSAIDs, the treatment modality and regimen for NSAID-induced small intestinal damage have remained relatively unclear. This article will provide a comprehensive overview of NSAID-induced small intestinal damage with regard to the epidemiology, clinical manifestations, diagnosis, risk factors, pathogenesis, and treatment, in order to provide informative evidence for clinical practice.

Sympathetic and Sensory-Motor Nerves in Peripheral Small Arteries

Small arteries, which play important roles in controlling blood flow, blood pressure, and capillary pressure, are under nervous influence. Their innervation is predominantly sympathetic and sensory motor in nature, and while some arteries are densely innervated, others are only sparsely so. Innervation of small arteries is a key mechanism in regulating vascular resistance. In the second half of the previous century, the physiology and pharmacology of this innervation were very actively investigated. In the past 10-20 yr, the activity in this field was more limited. With this review we highlight what has been learned during recent years with respect to development of small arteries and their innervation, some aspects of excitation-release coupling, interaction between sympathetic and sensory-motor nerves, cross talk between endothelium and vascular nerves, and some aspects of their role in vascular inflammation and hypertension. We also highlight what remains to be investigated to further increase our understanding of this fundamental aspect of vascular physiology.

Heteroreceptors Modulating CGRP Release at Neurovascular Junction: Potential Therapeutic Implications on Some Vascular-Related Diseases

Calcitonin gene-related peptide (CGRP) is a 37-amino-acid neuropeptide belonging to the calcitonin gene peptide superfamily. CGRP is a potent vasodilator with potential therapeutic usefulness for treating vascular-related disease. This peptide is primarily located on C- and Aδ-fibers, which have extensive perivascular presence and a dual sensory-efferent function. Although CGRP has two major isoforms (α-CGRP and β-CGRP), the α-CGRP is the isoform related to vascular actions. Release of CGRP from afferent perivascular nerve terminals has been shown to result in vasodilatation, an effect mediated by at least one receptor (the CGRP receptor). This receptor is an atypical G-protein coupled receptor (GPCR) composed of three functional proteins: (i) the calcitonin receptor-like receptor (CRLR; a seven-transmembrane protein), (ii) the activity-modifying protein type 1 (RAMP1), and (iii) a receptor component protein (RCP). Although under physiological conditions, CGRP seems not to play an important role in vascular tone regulation, this peptide has been strongly related as a key player in migraine and other vascular-related disorders (e.g., hypertension and preeclampsia). The present review aims at providing an overview on the role of sensory fibers and CGRP release on the modulation of vascular tone.

The therapeutic potential of histamine receptor ligands in inflammatory bowel disease

In the intestine of patients suffering from inflammatory bowel disease concentrations of histamine are increased compared to healthy controls. Genetic ablation of histamine production in mice ameliorates the course of experimentally induced colitis. These observations and first pharmacological studies indicate a function of histamine in the pathogenesis of inflammatory bowel disease. However, a closer examination reveals that available data are highly heterogeneous, limiting the rational design of strategies addressing specific histamine receptor subtypes as possible target for pharmacological interaction. However, very recently first clinical data indicate that antagonism at the histamine receptor subtype H4 provides a beneficial effect in at least the skin. Here, we discuss the available data on histamine effects and histamine receptor subtype functions in inflammatory bowel disease with a special emphasis on the histamine H4-receptor.

Efficacy of lafutidine, a histamine H2-receptor antagonist, for taxane-induced peripheral neuropathy in patients with gynecological malignancies

OBJECTIVE

Lafutidine, an antagonist of histamine H2-receptor, has gastroprotective activity associated with activation of capsaicin-mediated sensory nerves. The objective of this study was to investigate the efficacy of lafutidine for the treatment of taxane-induced peripheral neuropathy in patients with gynecological malignancies.

METHODS

Twenty patients with taxane-induced peripheral neuropathy during the treatment of gynecological malignancy were enrolled in this study. After obtaining their informed consent, lafutidine (20mg per day) was administered orally, the efficacy of which was assessed according to the Patient Neurotoxicity Questionnaire item 1.

RESULTS

Significant, moderate, slight, and no effects were observed in four, five, five, and six patients, respectively. The efficacy including significant and moderate effect was observed in nine (45%) of the 20 patients (95% confidence interval, 25.8%-65.8%). No adverse effects due to lafutidine were observed.

CONCLUSION

This pilot study supports the relatively high efficacy of lafutidine for the treatment of taxane-induced peripheral neuropathy. Further prospective studies are warranted.

An open-label, randomized, cross-over bioequivalence study of lafutidine 10 mg under fasting condition

AIM: To assess the relative bioavailability and pharmacokinetic properties of two formulations (test and reference) of Lafutidine 10 mg.

METHODS: The study was performed as an open label, randomized, two-way, two-period, two-treatment, single dose cross-over bioequivalence study, under non-fed condition to compare the pharmacokinetic profiles of the lafutidine formulation manufactured by Emcure Pharmaceuticals Ltd., India using an indigenously developed active pharmaceutical ingredient (API) and the commercially available Stogra^® formulation, of UCB Japan Co., Ltd., Japan. The two treatments were separated by a wash-out period of 5 d. After an overnight fasting period of 10 h, the subjects were administered either the test or the reference medication as per the randomization schedule. Blood samples were collected at intervals up to 24 h, as per the approved protocol. Concentrations of lafutidine in plasma were analyzed by a validated liquid chromatography/tandem mass spectrometry (LC/MS/MS) method, and a non-compartmental model was used for pharmacokinetic analysis. The pharmacokinetic parameters were subjected to a 4-way ANOVA accounting for sequence, subjects, period and treatment. Statistical significance was evaluated at 95% confidence level (P ≥ 0.05).

RESULTS: The mean (± SD) values of the pharmacokinetic parameters (test vs reference) were C_max (265.15 ± 49.84 ng/mL vs 246.79 ± 29.30 ng/mL, P < 0.05), Area under the curve (AUC)_(0-t) (1033.13 ± 298.74 ng.h/mL vs 952.93 ± 244.07 ng.h/mL, P < 0.05), AUC_(0-∞) (1047.61 ± 301.22 ng.h/mL vs 964.21 ± 246.45 ng.h/mL, P < 0.05), and t_½(1.92 ± 0.94 h vs 2.05 ± 1.01 h, P < 0.05). The 90% confidence intervals (CI) for the test/reference ratio of mean C_max, AUC_(0-t), and AUC_(0-∞) were within the acceptable range of 80.00 to 125.00. The mean times (± SD) to attain maximal plasma concentration (t_max) of lafutidine were 0.95 ± 0.24 h vs 1.01 ± 0.29 h (P < 0.05) for the test and the reference formulations respectively. Both the formulations were well tolerated.

CONCLUSION: In summary, this study has demonstrated the bioequivalence of the two formulations of lafutidine 10 mg. Hence it can be concluded that the two formulations can be used interchangeably in clinical settings.