Lafutidine, a protective H₂ receptor antagonist, enhances mucosal defense in rat esophagus

Recent Advances in the Pharmacological Management of Gastroesophageal Reflux Disease

The management of proton pump inhibitor-refractory GERD (rGERD) is a challenge in clinical practice. Since up to one-third of patients with typical GERD symptoms (heartburn and/or acid regurgitation) are not satisfied with proton pump inhibitor (PPI) therapy, new drug development targeting different pathophysiologies of GERD is imperative. At present, no other drugs serve as a more potent acid suppression agent than PPIs. As an add-on therapy, histamine type-2 receptor antagonists, alginates, prokinetics and transient lower esophageal sphincter relaxation inhibitors have some impact on the subgroups of rGERD, but greater effectiveness and fewer adverse effects for widespread use are required. Visceral hypersensitivity also contributes to the perception of GERD symptoms, and neuromodulators including antidepressants play a role in this category. Esophageal pH-impedance monitoring helps to distinguish functional heartburn from true GERD, and psychologic medication and cognitive behavior therapy are further therapy options instead of PPIs.

Efficacy of Lafutidine Versus Famotidine in Patients with Reflux Esophagitis: A Multi-Center, Randomized, Double-Blind, Non-inferiority Phase III Trial

BACKGROUND

There has been no study on the efficacy of lafutidine for patients with reflux esophagitis in Korea.

AIM

To evaluate the efficacy of a new-generation histamine-2 receptor antagonist, lafutidine, in comparison with famotidine in patients with reflux esophagitis.

METHODS

This was a randomized, double-blind, non-inferiority trial enrolling patients with erosive esophagitis. The efficacy and safety of 20 mg lafutidine (treatment group) were compared with those of 40 mg famotidine (control group) and 20 mg omeprazole (reference group). The primary endpoint was the complete healing rates of reflux esophagitis on endoscopy after 8 weeks of treatment. The non-inferiority margin was assumed to be -15 %.

RESULTS

The healing rates of reflux esophagitis on endoscopy after 8 weeks of treatment were 70.14 % (101/144) in the lafutidine, 63.45 % (92/145) in the famotidine, and 85.71 % (126/147) in the omeprazole group. The difference in healing rates between the lafutidine and famotidine groups was 6.69 % (95 % confidence interval = [-4.14 to 17.52]). In addition, lafutidine was superior to famotidine in clinical improvement (53.73 % vs. 39.55 %, P = 0.0200).

CONCLUSIONS

Lafutidine was non-inferior to famotidine in healing of reflux esophagitis. Lafutidine, however, was superior to famotidine in terms of symptom relief of reflux esophagitis.

Peripheral corticotropin-releasing factor receptor type 2 activation increases colonic blood flow through nitric oxide pathway in rats

BACKGROUND

Corticotropin-releasing factor (CRF) peptides exert profound effects on the secretomotor function of the gastrointestinal tract. Nevertheless, despite the presence of CRF peptides and receptors in colonic tissue, their influence on colonic blood flow (CBF) is unknown.

AIM

To determine the effect and mechanism of members of the CRF peptide family on CBF in isoflurane-anesthetized rats.

METHODS

Proximal CBF was measured with laser-Doppler flowmetry simultaneously with mean arterial blood pressure (MABP) measurement. Rats were injected with intravenous human/rat CRF (CRF1 > CRF2 affinity), mouse urocortin 2 (mUcn2, selective CRF2 agonist), or sauvagine (SVG, CRF2 > CRF1 affinity) at 1-30 µg/kg. The nitric oxide (NO) synthase inhibitor, L-NAME (3 mg/kg, iv), the cyclooxygenase inhibitor, indomethacin (Indo, 5 mg/kg, ip), or selective CRF2 antagonist, astressin2-B (Ast2B, 50 µg/kg, iv) was given before SVG injection (10 µg/kg, iv).

RESULTS

SVG and mUcn2 dose-dependently increased CBF while decreasing MABP and colonic vascular resistance (CVR). CRF had no effect on CBF, but increased CVR. The hyperemic effect of SVG was inhibited by L-NAME but not by Indo, whereas hypotension was partially reduced by L-NAME. Sensory denervation had no effect on SVG-induced changes. Ast2B inhibited SVG-induced hyperemia and decreased CVR, and partially reduced the hypotension.

CONCLUSIONS

Peripheral CRF2 activation induces colonic hyperemia through NO synthesis, without involving prostaglandin synthesis or sensory nerve activation, suggesting a direct action on the endothelium and myenteric neurons. Members of the CRF peptide family may protect the colonic mucosa via the activation of the CRF2 receptor.

Retrospective cohort study on combination therapy with the histamine H2-receptor antagonist lafutidine for antihistamine-resistant chronic urticaria

We conducted a retrospective cohort study evaluating the efficacy and usefulness of the addition of lafutidine, a novel histamine H2-receptor antagonist, in treatment of patients with idiopathic chronic urticaria whose disease was not well controlled with histamine H1-receptor antagonists. Based on the assessment of global improvement, moderate or better improvement was achieved in 39 of 46 patients (85%) after 1-3 weeks of additional administration of lafutidine and 35 patients (76%) after 3 months. No incidence of drug-related adverse reactions was reported in any patient. Lafutidine was rated as useful or better in 34 patients (74%) after 3 months of treatment. The usefulness of the drug was not affected by differences in background factors, such as disease duration, previous treatment duration and the number of concomitant H1-receptor antagonists. Lafutidine appears to be a promising addition to histamine H1-receptor antagonist therapy for the treatment of chronic urticaria resistant to treatment with H1-receptor antagonists alone.

Possible involvement of host defense mechanism in the suppression of rat acute reflux esophagitis by the particular histamine H2 receptor antagonist lafutidine

AIMS

Gastroesophageal reflux disease is considered to be caused primarily by gastric juice refluxed into the esophagus. Here, we investigated the possible involvement of host defense mechanisms in the development of acute reflux esophagitis using lafutidine, a histamine H(2) receptor antagonist (H(2)RA) with proven gastric mucosal protective effects.

METHODS AND RESULTS

The ligation of both the pylorus and the forestomach of SD rats under anesthesia caused hemorrhagic lesions in the esophageal mucosa at 6 h. Lesion formation was significantly inhibited by treatment with H(2)RAs, including the conventional H(2)RAs famotidine and cimetidine as well as lafutidine. The maximum suppressive abilities of these agents were similar to that of the proton pump inhibitor lansoprazole. Interestingly, unlike famotidine, lafutidine at low doses significantly suppressed esophagitis without inhibiting gastric acid secretion. Note that neither lafutidine nor famotidine inhibited hexosamine output in gastric juice samples obtained 3 h after ligation. Additionally, the protective effect of lafutidine, but not of famotidine, was partly attenuated by the denervation of capsaicin-sensitive afferent nerves with a large dose of capsaicin.

CONCLUSION

The present results indicate that esophageal host-defense via capsaicin-sensitive afferent nerves may contribute to the therapeutic action of lafutidine.

Oesophageal sensation in response to high PCO(2) and acidic solutions in nonerosive reflux disease

BACKGROUND

Heartburn is commonly associated with the presence of acid in the oesophageal lumen. However, in patients with nonerosive reflux disease (NERD), the mechanism by which acid traverses the mucosa is not clear. We hypothesized that the luminal acid signal traverses the oesophageal epithelium in the form of the highly permeant gas CO(2) , which then is reconverted to H(+) in the submucosa.

MATERIALS AND METHODS

  Ten patients with heartburn, normal upper endoscopy and increased oesophageal acid exposure (NERD patients) and 10 healthy subjects were enrolled. Perceptual responses to intraoesophageal acid (0·1 N HCl solution) and a high PCO(2) solution were determined using a randomized cross over design. Stimulus-response functions to perfusions were quantified by three parameters: lag time to symptom perception, intensity rating and perfusion sensitivity score.

RESULTS

 In NERD patients, the difference in lag time to typical symptom perception, intensity rating and perfusion sensitivity score between high PCO(2) and acid perfusions was statistically significant (P = 0·02, 0·01 and 0·02, respectively). However, the difference in the same perfusion parameters between acid and high PCO(2) perfusions was nonsignificant in healthy controls. When NERD and controls were compared, the difference between the different perfusion variables was nonsignificant (adjusted to age).

CONCLUSIONS

In NERD subjects, acid perfusion reliably evoked heartburn symptoms of greater intensity than in healthy controls. Nevertheless, a high PCO(2) perfusion failed to produce symptoms in either group.

Application of UV spectrophotometric method for easy and rapid estimation of lafutidine in bulk and pharmaceutical formulation

INTRODUCTION

The present research work discusses the development of a UV estimation method for lafutidine. Simple, accurate, cost efficient, and reproducible spectrophotometric method has been developed for the estimation of Lafutidine in bulk and pharmaceutical dosage form.

MATERIALS AND METHODS

The Stock solution was prepared in a mixture of water and methanol (1:1). Further dilutions were made in water.

RESULTS

The drug was determined at maximum wavelength (λmax) 279 nm. Beers law was obeyed in the concentration range of 10-50 μg/ml having line equation y = 0.0100x + 0.035 with correlation coefficient of 0.999. Results of the analysis were validated statistically and by recovery study.

CONCLUSION

The result of analysis was validated as per ICH guidelines and this method can be used for the routine analysis of lafutidine formulation.