Inhibitors of gastric acid secretion increase oxidative stress and matrix metalloproteinase-2 activity leading to vascular remodeling.

The use of inhibitors of gastric acid secretion (IGAS), especially proton pump inhibitors (PPI), has been associated with increased cardiovascular risk. While the mechanisms involved are not known, there is evidence supporting increased oxidative stress, a major activator of matrix metalloproteinases (MMP), as an important player in such effect. However, there is no study showing whether other IGAS such as histamine H2-receptor blockers (H2RB) cause similar effects. This study aimed at examining whether treatment with the H2RB ranitidine promotes oxidative stress resulting in vascular MMP activation and corresponding functional and structural alterations in the vasculature, as compared with those found with the PPI omeprazole. Male Wistar rats were treated (4 weeks) with vehicle (2% tween 20), omeprazole (10 mg/Kg/day; i.p.) or ranitidine (100 mg/Kg/day; gavage). Then the aorta was collected to perform functional, biochemical, and morphometric analysis. Both ranitidine and omeprazole increased gastric pH and oxidative stress assessed in situ with the fluorescent dye dihydroethidium (DHE) and with lucigenin chemiluminescence assay. Both IGAS augmented vascular activated MMP-2. These findings were associated with aortic remodeling (increased media/lumen ratio and number of cells/µm2). Both IGAS also impaired the endothelium-dependent relaxation induced by acetylcholine (isolated aortic ring preparation). This study provides evidence that the H2RB ranitidine induces vascular dysfunction, redox alterations, and remodeling similar to those found with the PPI omeprazole. These findings strongly suggest that IGAS increase oxidative stress and matrix metalloproteinase-2 activity leading to vascular remodeling, which helps to explain the increased cardiovascular risk associated with the use of those drugs.

Profilaxis para sangrado gastrointestinal en pacientes del servicio de medicina interna de un hospital universitario / Gastrointestinal bleeding prophylaxis in internal medicine patients of a univeristy hospital

Introducción: Los medicamentos antiulcerosos son utilizados frecuentemente en pacientes hospitalizados, sin embargo, a menudo este uso no está indicado. Objetivo: Describir la frecuencia de prescripción e indicación de medicamentos para prevenir el sangrado gastrointestinal en pacientes hospitalizados. Materiales y métodos: Estudio de corte trasversal, descriptivo, prospectivo del servicio de Medicina Interna de la Sociedad de Cirugía de Bogotá- Hospital de San José de Bogotá, Colombia. Se excluyeron pacientes con diagnóstico de sangrado gastrointestinal o antecedente de alergia a los medicamentos antiulcerosos. Se recolectaron datos demográficos, así como fármacos prescritos. Se determinó si la indicación del fármaco era adecuada y se identificó el tipo de error de prescripción. Resultados: Se incluyeron 179 pacientes, 102 (57%) mujeres. Promedio de edad de 61,3 años (±20,2). El principal diagnóstico de ingreso fue enfermedad infecciosa 76 (42,4%). Del total de pacientes, 165 (92,17%) recibieron medicamento para prevención del sangrado gastrointestinal. La indicación fue adecuada en 75 pacientes (41,89%). El error más frecuente fue el uso en pacientes de bajo riesgo de sangrado, 101 (97,1%). Conclusión: Un alto porcentaje de los pacientes recibió medicación para la prevención del sangrado gastrointestinal. En aproximadamente la mitad de estos no estaba indicada.

Introduction: Anti-ulcer medications are frequently used in hospitalized patients, yet their use is not usually indicated. Objective: To describe the frequency of prescription and indication of medications to prevent gastrointestinal bleeding in hospitalized patients. Materials and methods: A cross-sectional, descriptive, prospective study was carried out in the Internal Medicine service of the Surgery Society of Bogota-San Jose Hospital of Bogota (Colombia). Excluded patients were those with either a gastrointestinal bleeding diagnosis or a history of allergy to anti-ulcer medications. Demographic data and information regarding prescribed medications were collected. It was determined whether the medicine indication was adequate and the type of prescription error was identified. Results: 179 patients were included in the study, 57% (102) of which were women. The average age was 61.3 (±20.2) years old. Infectious disease was the main admission diagnosis (76; 42.4%). A 92.17% (165) of the total number of patients received medications to prevent gastrointestinal bleeding. This indication was adequate for 75 (41.89%) patients. The most frequent error was their use in bleeding low-risk patients (101; 97.1%). Conclusion: A high percentage of patients received medication to prevent gastrointestinal bleeding. However, in about half of these patients it was not indicated.

Preparation of Co-Processed Excipients for Controlled-Release of Drugs Assembled with Solid Lipid Nanoparticles and Direct Compression Materials.

The purpose of the study was to develop a novel, directly compressible, co-processed excipient capable of providing a controlled-release drug system for the pharmaceutical industry. A co-processed powder was formed by adsorption of solid lipid nanoparticles (SLN) as a controlled-release film onto a functional excipient, in this case, dicalcium phosphate dihydrate (DPD), for direct compression (Di-Tab®). The co-processed excipient has advantages: easy to implement; solvent-free; industrial scaling-up; good rheological and compressibility properties; and the capability to form an inert platform. Six different batches of Di-Tab®:SLN weight ratios were prepared (4:0.6, 3:0.6, 2:0.6, 1:0.6, 0.5:0.6, and 0.25:0.6). BCS class III ranitidine hydrochloride was selected as a drug model to evaluate the mixture's controlled-release capabilities. The co-processed excipients were characterized in terms of powder rheology and dissolution rate. The best Di-Tab®:SLN ratio proved to be 2:0.6, as it showed high functionality with good flow and compressibility properties (Carr Index = 16 ± 1, Hausner Index = 1.19 ± 0.04). This ratio could control release for up to 8 h, so it fits the ideal profile calculated based on biopharmaceutical data. The compressed systems obtained using this powder mixture behave as a matrix platform in which Fickian diffusion governs the release. The Higuchi model can explain their behavior.

Logic of Selecting Suitable Dissolution Parameters in New Drug Formulations Based on A BCS Approach.

Since the biopharmaceutical quality of generic drug formulations depends on the quality of the reference products and also information about the in-vitro release performance of drugs under different conditions is scarce in the literature, a dissolution study of four reference tablets was performed. Each drug was representative of one Class of the Biopharmaceutical Classification System. The in-vitro release performance of propranolol-HCl, carbamazepine, ranitidine-HCl, and metronidazole was evaluated using a USP basket and paddle apparatus at different agitation rates (50, 75, and 100 rpm) with two doses of each drug. In all experiments, pharmacopeial dissolution media was used and the samples were taken with automatic equipment at specific times up to 60 min, except for propranolol-HCl, for which the samples were taken up to 30 min. The dissolution profiles were compared by model-independent, model-dependent, and ANOVA-based comparisons. The three methods of data comparison showed that low vs. high doses were significantly different (P < 0.05), which may influence cases in which biowaivers of propranolol-HCl and ranitidine-HCl are requested. Additionally, the results showed that despite different hydrodynamic environments produced by the basket and paddle apparatus, under certain conditions, both types of equipment generated comparable in-vitro results. Variables such as the dose, agitation rate, and type of dissolution apparatus are important factors to consider in designing dissolution tests for drug products. This information can be used to test a new dosage when there is no pharmacopeial method available to perform a dissolution study. Further researches on the in-vitro release performance of reference drug products are required.

Consistent gastric pH-dependent effects of suppressors of gastric acid secretion on the antihypertensive responses to oral nitrite.

Proton pump inhibitors (PPI) are suppressors of gastric acid secretion (SGAS) that decrease gastric nitric oxide (NO) formation from nitrite and increase the cardiovascular risk. However, H2 receptor antagonists (H2RA) are considered safer than PPIs. We challenged this notion and hypothesized that both omeprazole (PPI) and ranitidine (H2RA) attenuate the responses to oral nitrite because both drugs increase gastric pH and therefore could decrease nitrite-derived NO formation in the stomach. We examined the blood pressure responses to oral nitrite in hypertensive rats treated with omeprazole, ranitidine, or vehicle. Chemiluminensce-based assays were used to measure gastric NO formation, plasma and gastric concentrations of nitrite, nitrate, and nitrosylated species (RXNO) to clarify the mechanism involved in the effects of SGAS on the responses to oral nitrite. Both drugs increased gastric pH, impaired oral nitrite-induced hypotensive responses, gastric NO formation, and blunted the increases in circulating RXNO concentrations, but not in circulating nitrite and nitrate concentrations. These findings were reproduced in a second study using sodium acetate buffers at pH 3.5, 4.5, and 5.5 to mimic gastric pH found with vehicle, ranitidine, and omeprazole, respectively. Increasing gastric pH impaired oral nitrite-induced hypotensive responses, gastric NO formation, and blunted the increases in circulating RXNO concentrations, but not in circulating nitrite and nitrate concentrations. Our results clearly indicate that SGAS impair nitrite-induced gastric formation of NO and vasoactive RXNO in a pH-dependent manner, thus resulting in impaired responses to oral nitrite. These findings may have several clinical implications, particularly to patients with cardiovascular diseases.

Involvement of histamine H1 and H2 receptor inverse agonists in receptor's crossregulation.

Histamine [2-(4-Imidazolyl)-ethylamine] modulates different biological processes, through histamine H1 and H2 receptors, and their respective blockers are widely used in treating allergic and gastric acid-related disorders. Histamine H1 and H2 receptor crossdesensitization and cointernalization induced by its agonists have been previously described. In this study, we show how this crosstalk determines the response to histamine H1 and H2 receptor inverse agonists and how histamine H1 and H2 receptor inverse agonists interfere with the other receptor's response to agonists. By desensitization assays we demonstrate that histamine H1 and H2 receptor inverse agonists induce a crossregulation between both receptors. In this sense, the histamine H1 receptor inverse agonists desensitize the cAMP response to amthamine, a histamine H2 receptor agonist. In turn, histamine H2 receptor inverse agonists interfere with histamine H1 receptor signaling. We also determine that the crossdesensitization induced by histamine H1 or H2 receptor agonists alters the histamine inverse agonists receptor response: activation of histamine H1 receptor affects cAMP response induced by histamine H2 receptor inverse agonists, whereas histamine H2 receptor agonist induces a negative regulation on the anti-inflammatory response of histamine H1 receptor inverse agonists. Binding studies revealed that histamine H1 and H2 receptors cointernalize after stimulus with histamine receptor inverse agonists. In addition, the inhibition of the internalization process prevents receptor crossregulation. Our study provides new insights in the mechanisms of action of histamine H1 and H2 receptors that explain the effect of histamine H1 and H2 receptor inverse agonists and opens up new venues for novel therapeutic applications.

Effect of mutation of Phe 2436.44 of the histamine H2 receptor on cimetidine and ranitidine mechanism of action.

Despite the pivotal role GPCRs play in cellular signaling, it is only in the recent years that structural biology has begun to elucidate how GPCRs function and to provide a platform for structure-based drug design. It is postulated that GPCR activation involves the movement of transmembrane helices. The finding that many residues, which have been shown to be critical for receptor activation and are highly conserved among different GPCRs, are clustered in particular positions of transmembrane helices suggests that activation of GPCRs may involve common molecular mechanisms. In particular, phenylalanine 6.44, located in the upper half of TMVI, is highly conserved among almost all GPCRs. We generated Phe 2436.44 Ala/Ser mutants of histamine H2 receptor and found that while the substitutions do not affect receptor expression or ligand signaling, are able to specifically alter cimetidine and ranitidine mechanisms of action from simply inactivating the receptor to produce a ligand-induced G-protein sequestering conformation, that interferes with the signaling of ß2-adrenoceptor. Taking advantage of the cubic ternary complex model, and mathematically modeling our results, we hypothesize that this alteration in ligand mechanism of action is consequence of a change in ligand-induced conformational rearrangement of receptor and its effect on G-protein coupling. Our results show that receptor point mutations can not only alter receptor behavior, as shown for activating/inactivating mutations, but also can have more subtle effects changing ligand mechanism of action.

Use of ranitidine is associated with infections in newborns hospitalized in a neonatal intensive care unit: a cohort study.

BACKGROUND: The inhibition of gastric acid secretion with ranitidine is frequently prescribed off-label to newborns admitted to neonatal intensive care units (NICU). Some studies show that the use of inhibitors of gastric acid secretion (IGAS) may predispose to infections and necrotising enterocolitis (NEC), but there are few data to confirm this association. This study aimed to compare the rates of neonatal infections and NEC among preterm infants (<37 weeks gestation) hospitalised in a NICU exposed or not to treatment with ranitidine. METHODS: A retrospective cohort study was conducted with all consecutive preterm newborns admitted to a NICU between August-2014 and October-2015. The rates of infection, NEC, and death of newborns exposed or not to ranitidine were recorded. RESULTS: A total of 300 newborns were enrolled, of which 115 had received ranitidine and 185 had not. The two groups were similar with regard to the main demographic and clinical characteristics. Forty-eight (41.7%) of the 115 infants exposed to ranitidine and 49 (26.5%) of the 185 infants not exposed were infected (RR = 1.6, 95%CI 1.1-2.2, p = 0.006). The late onset (>48 h) blood culture positive infection rate was higher in the group exposed to ranitidine than in the untreated group (13.0% vs. 3.8%, p = 0.001). There was no significant association between the use of ranitidine and NEC (Bell stage >II) (p = 0.36). The mortality rate risk was 4-fold higher in infants receiving ranitidine (16.5% vs. 8.6%, p < 0.001). CONCLUSION: Ranitidine use in neonates was associated with an increased risk of infections and mortality, but not with NEC.

Pharmacokinetics of ranitidine in preterm and term neonates with gastroesophageal reflux.

BACKGROUND: The aim of this study was to determine the effect of gestational age on pharmacokinetics of ranitidine in newborns with gastroesophageal reflux. METHODS: A prospective, descriptive and pharmacokinetic study was carried out in 30 pre-term and 20 full-term babies. 3 mg/kg of ranitidine was administered intravenously to all the babies and at 0.25, 0.5, 1, 2, 4, and 8 h following the administration, samples of blood were drawn to assess ranitidine levels using high performance liquid chromatographic technique. RESULTS: Pharmacokinetics of ranitidine had a bi-exponential behavior with a half-life elimination of (t1/2el) 2.79 h, area under curve (AUC) of 1688 ng/mL, volume of distribution (Vd) of 1.44 L/kg, and clearance (Cl) of 5.9 L/kg/h. The median plasmatic concentration in pre-terms was 1113 ng/mL and 280 ng/mL in full-terms. Vd, t1/2 and Cl presented high values in preterm although the correlation of Cl with glomerular filtration in term newborns was better. CONCLUSIONS: Plasma levels of ranitidine depend on the gestational age of the newborns. However, the possible relationship between after-birth age and pharmacokinetics of the neonates as their internal organs get matured without minding their gestational background.

ADMINISTRATION OF H2 BLOCKERS IN NSAID INDUCED GASTROPATHY IN RATS: effect on histopathological changes in gastric, hepatic and renal tissues

ABSTRACT Background Nonsteroidal anti-inflammatory drugs induces gastric mucosal lesions because of its acidic properties. Ranitidine, an H2 receptor antagonist, has proved beneficial in patients with gastric ulcers. Objective The present study was performed to assess the effect of administering ranitidine in Nonsteroidal anti-inflammatory drugs (diclofenac, nimesulide) induced gastropathy, and their effect on the histopathology of stomach, kidney and liver. Methods Diclofenac, nimesulide, and ranitidine were administered in doses of 2, 4, and 6 mg/kg, p.o. once daily for 14 days, and their effect on gastric volume, acidity, mean ulcer number, and gastric pH. In addition, histopathological examination was also performed on sections of stomach, kidney and liver. Results Following the administration of diclofenac or nimesulide, all the gastric parameters were significantly altered as well as the histopathology of stomach, liver and kidney. In the control group, the renal sections showed normal glomeruli with no thickening of glomerular basement membrane, while in diclofenac alone, nimesulide alone, and ranitidine with nimesulide groups, the thickening of glomerular basement membrane was observed. These alterations were observed to be reversed in the ranitidine with diclofenac group. In the sections from the liver, the control group showed anastomosing plates and cords of cuboidal hepatocytes with round well stained nuclei and abundant cytoplasm. In the ranitidine with diclofenac, and ranitidine with nimesulide groups, mild dilatation of sinusoids is seen coupled with prominence of central vein. In the diclofenac alone and nimesulide alone groups, the proximal and distal convoluted tubules show mild focal tubular necrosis. In the gastric sections, the control group showed several folds forming villi, and the epithelial lining surface of the mucosa. In the ranitidine with diclofenac, and ranitidine with nimesulide groups, the duodenum showed scattered inflammatory cells composed predominantly of lymphocytes. In diclofenac alone and nimesulide alone group, the sections from the gastric areas showed partial necrosis and mild chronic inflammation respectively. Conclusion The study, therefore, has provided therapeutic rationale towards simultaneous administration of H2 receptor blocker ranitidine with diclofenac to be more beneficial as compared to ranitidine with nimesulide, to minimise the gastric intolerance of diclofenac in long term treatment of inflammatory conditions.

RESUMO Contexto Anti-inflamatórios não esteroidais induzem lesões da mucosa gástrica devido às suas propriedades ácidas. Ranitidina, um antagonista dos receptores H2, revelou-se benéfico em pacientes com úlceras gástricas. Objetivo - O presente estudo foi realizado para avaliar o efeito da administração de ranitidina em gastropatia induzida por anti-inflamatórios não esteroidais (diclofenaco, nimesulida) e seu efeito sobre a histopatologia do estômago, dos rins e fígado. Métodos Diclofenaco, nimesulida e ranitidina foram administradas em doses de 2, 4 e 6 mg/kg, p.o. uma vez diariamente por 14 dias e seu efeito sobre o volume gástrico, acidez, significam o número de úlcera e o pH gástrico. Além disso, o exame histopatológico também foi realizado em seções do estômago, dos rins e fígado. Resultados Após a administração de diclofenaco ou nimesulida, todos os parâmetros gástricos foram significativamente alterados assim como a histopatologia do estômago, fígado e rim. No grupo controle, as seções renais mostraram glomérulos normais sem espessamento da membrana basal glomerular, enquanto em diclofenaco isolado, nimesulida isolado e grupos com ranitidina e nimesulida, foi observado espessamento da membrana basal glomerular. Estas alterações observou-se serem revertidas no grupo ranitidina com diclofenaco. As seções do fígado, o grupo controle mostrou placas e cordões de hepatócitos cuboidais anastomosados com núcleos bem demarcados e citoplasma abundante. Nos grupos ranitidina com diclofenaco e ranitidina com nimesulida, leve dilatação dos sinusoides é vista acoplados com proeminência de veia central. Nos grupos diclofenaco e nimesulida sozinhos, túbulos proximais e distais contorcidos mostram necrose tubular focal leve. Nas secções gástricas, o grupo controle mostrou várias dobras formando vilosidades e a superfície do revestimento epitelial da mucosa. Nos grupos ranitidina com diclofenaco e ranitidina com nimesulida, o duodeno mostrou dispersas células inflamatórias predominantemente compostas por linfócitos. Nos grupos diclofenaco e nimesulida sozinhos, as secções de áreas gástricas mostraram necrose parcial e inflamação crônica moderada respectivamente. Conclusão - O estudo, portanto, forneceu o fundamento terapêutico para administração simultânea de bloqueador de receptor H2 (ranitidina) com diclofenaco, sendo mais benéfica em comparação com ranitidina com nimesulida para minimizar a intolerância gástrica de diclofenaco no tratamento a longo prazo de condições inflamatórias.

Preparation and Physical Characterization of a Diclofenac-Ranitidine Co-precipitate for Improving the Dissolution of Diclofenac.

Mixing aqueous solutions of sodium diclofenac (DIC-Na) and ranitidine hydrochloride (RAN·HCl) afforded an off-white solid (DIC-RAN) that was investigated from the microscopic, thermal, diffractometric, spectroscopic, and functional (chemometrics-assisted dissolution) points of view. The solid has a 2:1 (DIC:RAN) molar ratio according to (1)H nuclear magnetic resonance spectroscopy. It is thermally stable, displaying a broad endothermic signal centered at 105°C in the thermogram, and its characteristic reflections in the powder X-ray diffractogram remained unchanged after a 3-month aging period. Scanning electron microscopy micrographs uncovered its morphology, whereas the spectral data suggested an interaction between the carboxylic acid of DIC and the alkyldimethylamino moiety of RAN. The dissolution of DIC-RAN was monitored at different pH values by an ultraviolet/chemometrics procedure, being complete within 5 min at pH 6.8. This compares favorably with the dissolution of a DIC-Na sample of the same particle size.

Uso de inhibidores de la bomba de protones y antagonistas de los receptores H2 de histamina como profilaxis en úlceras por estrés: ¿una práctica justificada? / Use of proton pump inhibitors and Histamine-2 receptor antagonists in stress ulcers: a justified practice? / Uso de inibidores da bomba de prótons e antagonistas dos receptores H2 de histamina como profilaxia em úlceras por estresse: uma prática justificada?

La introducción de los moduladores de acidez gástrica como profilaxis contra las úlceras por estrés en pacientes críticos se ha \r\nido convirtiendo en una práctica de rutina tanto en la unidad de cuidados intensivos como fuera de esta; sin embargo, el desco\r\n-\r\nnocimiento de la fisiopatología de la enfermedad, las indicaciones de uso de moduladores de pH como profilácticos, los riesgos \r\nasociados a la prescripción indiscriminada y de las guías disponibles sobre esta práctica han llevado a un uso descontrolado \r\nde medicamentos como omeprazol y ranitidina, lo cual aumenta los costos para los hospitales y predispone a los pacientes a \r\npresentar enfermedades como neumonía. Con el objetivo de revisar los factores de riesgo asociados a esta patología, la eficacia \r\nde esta medida, sus indicaciones y posibles complicaciones tanto dentro como fuera de las unidades de cuidados intensivos, se \r\nrealizó una revisión de la literatura. Esta incluyó artículos disponibles en diferentes bases de datos que hicieran referencia al manejo \r\nprofiláctico de úlceras por estrés desde 1980 hasta 2014. Se encontró que, según la literatura actual, el uso de la profilaxis contra \r\núlceras por estrés es una práctica muy debatida en el caso de los pacientes críticos y, lo que es más importante, en los no críticos \r\naún no existen recomendaciones de uso o factores de riesgo establecidos. Por esta razón, la extrapolación de esta conducta a \r\npacientes fuera de la unidad de cuidados intensivos es injustificada hasta el momento.

The introduction of acid gastric modulators in critical patients \r\nas prophylaxis against stress ulcers has increasingly become \r\na routine practice both in the intensive care unit and outside \r\nof it. However, lack of knowledge about topics including \r\nthe physiopathology of the disease, directions for use of pH \r\nmodulators as a prophylactic, the associated risk of over-pre\r\n-\r\nscription, and guidelines available about this practice has led \r\nto an overuse of drugs like omeprazole and ranitidine, making \r\nhospitalization more expensive and predisposing patients \r\nto diseases like pneumonia. The objective of this article is \r\nto review the risk factors associated with this pathology, the \r\nefficacy of this action, and the complications and indications \r\ninside and outside of intensive care units using all available \r\ndata through 2014. In the end we conclude that at this time \r\nand with the new evidence, the use of prophylaxis against \r\nstress ulcers in critical patients is a widely debated practice and \r\nmore importantly there are no recommendations for its use or \r\nestablished risk factors in the non-critical population, leading \r\nus to conclude that extrapolation to patients outside of inten\r\n-\r\nsive care is not justified up to date.

A introdução dos moduladores de acidez gástrica como \r\nprofilaxia contra as úlceras por estresse em pacientes críticos \r\nconverteu-se em prática de rotina tanto na unidade de cuidados \r\nintensivos como fora desta. No entanto, o desconhecimento \r\nda fisiopatologia da doença, as indicações de uso de modula\r\n-\r\ndores de pH como profiláticos, os riscos associados à prescrição \r\nindiscriminada e as orientações disponíveis sobre esta prática \r\nlevaram a um uso descontrolado de medicamentos como \r\nomeprazol e ranitidina, aumentando o custo para os hospi\r\n-\r\ntais e predispondo os pacientes a doenças como pneumonia. \r\nCom o objetivo de revisar os fatores de risco associados a esta \r\npatologia, a eficácia desta medida, suas indicações e possí\r\n-\r\nveis complicações tanto dentro como fora das unidades de \r\ncuidado intensivo, foi realizada uma revisão da literatura. Esta \r\nincluiu artigos disponíveis em diferentes bancos de dados que \r\nse referiram ao manuseio profilático de úlceras por estresse, \r\ndesde 1980 até 2014. Descobriu-se que, segundo a literatura \r\natual, o uso de profilaxia contra úlceras por estresse é uma \r\nprática muito debatida no caso dos pacientes críticos e, o que \r\né mais importante, para os não críticos ainda não existem reco\r\n-\r\nmendações de uso ou fatores de risco estabelecidos. Por este \r\nmotivo, a extrapolação desta conduta com pacientes fora da \r\nunidade de cuidados intensivos é injustificada até o momento.

Gastroprotective activity of the hydroethanolic extract and isolated compounds from the leaves of Solanum cernuum Vell.

ETHNOPHARMACOLOGICAL RELEVANCE: Solanum cernuum Vell. (Solanaceae) is a Brazilian medicinal plant, traditionally known as "panaceia". Its folk name is probably due to its wide range of applications in traditional medicine including the treatment of ulcers. AIM OF THE STUDY: To evaluate the gastroprotective activities of the hydroethanolic extract (ESC) of S. cernuum and its major isolated compounds using in vivo gastric ulcer models. MATERIAL AND METHODS: The ESC extract was obtained by maceration followed by percolation of the dried and powdered leaves of S. cernuum in ethanol:water (7:3). The major compounds in the extract were isolated by applying various preparative chromatographic techniques. The gastroprotective activity was evaluated in mice using different gastric ulcer-induced models. The anti-Helicobacter pylori activity was performed using the agar-well diffusion and broth microdilution methods. RESULTS: The ESC extract showed gastroprotective effects in the assay of acute gastric ulcer-induced by HCl/EtOH, nonsteroidal anti-inflammatory drug, and acetic acid-induced chronic ulcer protocols. The results also demonstrated that the gastroprotection induced by ESC extract is related to the activity of nitric oxide and endogenous sulfhydryls, which are important gastroprotective factors. The ESC extract and the alkaloid cernumidine did not show activity against H. pylori in the concentrations tested. CONCLUSIONS: The present study showed that the crude extract of S. cernuum possessed gastroprotective activity which corroborating the traditional use of this plant for the treatment of gastric ulcers. The isolated flavonoids, quercitrin and afzelin as well as the phenylpropanoid, isoferulic acid are suggested to be the compounds responsible for the gastroprotective activity of S. cernuum extract.

Helicteres sacarolha A. St.- Hil. et al.: gastroprotective and possible mechanism of actions in experimental animals.

ETHNOPHARMACOLOGICAL RELEVANCE: Helicteres sacarolha A. St.- Hil. et al. popularly known in Brazil as 'semente-de-macaco', is widely employed in the popular medicine in many of parts of Brazil in the alleviation of symptoms of ailments such as peptic ulcer and inflammation. Up to the present, there is no study addressing the gastroprotective activity of the hydroethanolic extract of H. sacarolha and its possible mechanism of actions. MATERIALS AND METHODS: The hydroethanolic (70%) extract of H. sacarolha (HEHs) was obtained by maceration. The gastroprotective activity was assessed using gastric ulcer models induced by acidified ethanol, piroxicam, and water restraint stress in mice and rats at doses of 20, 50 and 250mg/kg p.o. Mechanistic studies involved the antisecretory assay evaluated with pylorus ligation in rats and pre-treatments with appropriate antagonists/inhibitors such as yohimbine, glibenclamide, indomethacin and l-NAME, effect on catalase and myeloperoxidase activities and gastric mucus determination using acidified ethanol- induced ulcer in mice. RESULTS: HEHs at all doses tested demonstrated potent gastroprotective activities in the acute ulcer models. The gastroprotective activity of HEHs was attenuated by pre-treatments with yohimbine, glibenclamide, indomethacin and l-NAME. HEHs effectively reduced basal gastric juice production without any effect on the free and total acidity. The gastroprotective action of HEHs involved increasing the antioxidant enzyme catalase and mucus secretion and inhibition of neutrophyl infiltration as reflected by the reduction in the myeloperoxidase activity. CONCLUSION: The results of this study gave a scientific support for the popular use of the leaves of H. sacarolha in the treatment of gastric ulcers and that it has a multi-targeted action.

Comparação entre a ranitidina e o omeprazol em relação a possíveis interações medicamentosas com o clopidogrel em pacientes portadores de doenças arterial coronária estável / Possible drug interaction between clopidogrel and ranitidin or omeprazole in patients with stable coronary artery disease: a comparative study

INTRODUÇÃO: Os Inibidores de Bombas de Prótons (IBP´s) são comumente prescritos a pacientes em uso de dupla antiagregação plaquetária (DAP) com ácido acetilsalicílico (AAS) e clopidogrel. Entretanto, esta classe de medicamentos, especialmente o omeprazol, tem sido associada à redução da potência antiplaquetária do clopidogrel, levando em muitos casos ao uso de ranitidina como alternativa. MÉTODOS: Foram analisados pacientes com doença arterial coronária (DAC) estável em uso de AAS 100 mg uma vez ao dia. A agregabilidade plaquetária foi medida no momento basal e após uma semana de terapia com clopidogrel na dose de 75 mg uma vez ao dia. Após essa fase inicial, os participantes foram randomizados de modo duplo-cego e duplo-mascarado para omeprazol 20 mg duas vezes dia ou ranitidina 150 mg duas vezes ao dia, sendo os testes de agregação plaquetária novamente repetidos após uma semana. A agregabilidade foi avaliada com a utilização dos seguintes métodos: VerifyNow P2Y12® (Accumetrics - San Diego, CA, EUA, meta principal do estudo), utilizando-se Unidades de Reatividade ao P2Y12 ("P2Y12 Reactivity Units" - PRU) e Inibição Percentual da Agregabilidade (IPA) na descrição da agregabilidade; agregometria de sangue total (AST) por bioimpedância utilizando os reagentes ADP e colágeno, sendo a agregabilidade medida em Ohms; "Platelet Function Analyser" 100® (Siemens Healthcare Diagnostics®, Newark, Delaware, EUA) utilizando o cartucho de colágeno/ADP, com a agregabilidade avaliada pelo tempo de fechamento do orifício em segundos. Além disso, foi feita dosagem de tromboxano B2 (TXB2) sérico na última visita a fim de se avaliar o efeito do AAS. RESULTADOS: Oitenta e cinco pacientes foram incluídos na análise final, sendo 41 no grupo omeprazol e 44 no grupo ranitidina. Houve redução significativa da IPA após o acréscimo de omeprazol (de 26,3 ± 32,9% para 17,4 ± 33,1%; P = 0,025), enquanto o grupo ranitidina não demonstrou modificação significativa (de 32,6 ± 28,9% para...

BACKGROUND: Proton-pump inhibitors (PPIs) are often prescribed to patients taking dual antiplatelet therapy (DAPT) with acetylsalicylic acid (ASA) and clopidogrel. However, this class of medication, especially omeprazole, has been associated with a reduction of clopidogrel efficacy, leading many to substitute omeprazole with ranitidine. METHODS: The present study analyzed patients with stable coronary artery disease (CAD) in use of ASA 100 mg daily. Platelet aggregability was measured at baseline and after one week of clopidogrel 75 mg daily. Then, the subjects were randomized, in a double-blinded, doubledummy fashion, to omeprazole 20 mg twice a day or ranitidine 150 mg twice a day. After one more week, aggregability tests were repeated. Platelet aggregability was evaluated by the following methods: VerifyNow P2Y12TM (Accumetrics - San Diego, California, USA, main endpoint of the study), with aggregability depicted as percent Inhibition of Platelet Aggregation (IPA) and as P2Y12 Reactivity Units (PRU); whole blood aggregometry by bioimpendance using ADP and collagen with aggregability measured in Ohms; and Platelet Function Analyser 100TM (Siemens Healthcare Diagnostics, Newark, Delaware, USA) using collagen/ADP cartridge with aggregability measured in time to closure in seconds. Besides that, serum thromboxane B2 dosage was done on the last visit to evaluate ASA effect. RESULTS: Eighty-five patients were included in final analysis (41 in the omeprazole group and 44 in the ranitidine group). IPA was significantly decreased after addition of omeprazole (from 26.3% ± 32.9 to 17.4% ± 33,1; P = 0.025), with no significant changes being observed in the ranitidine group (from 32.6% ± 28.9 to 30.1% ± 31.3; P = 0.310). When taking into account PRU values, there was a numerical, but statistically non-significant increase in the omeprazole group (from 159.73 ± 83.06 to 173.54 ± 72.29; P = 0.116), with a very slight difference in the ranitidine group (from 153.61 ±...

Metabolic profile and ruminal and abomasal pH in sheep subjected to intravenous ranitidine / Perfil metabólico ruminal e pH abomasal em ovinos tratados com ranitidina por via intravenosa

Brazilian sheep production has intensified, predisposing sheep to an increased incidence of digestive disorders, such as abomasal ulcers. Ranitidine is used to prevent and treat this disease; however, there is little information on the parenteral use of this drug in adult ruminants. Few data exist on the concomitant metabolic changes and the behavior of the digestive system associated with its use. For this study, five healthy male sheep with ruminal and abomasal cannulas were used. A 5x5 Latin square experiment with a 2x2+1 factorial arrangement of the treatments was performed. Sheep treated with drug doses of 1 or 2mg/kg ranitidine administered intravenously every 8 or 12 hours were compared with the control group, was treated intravenously with 1 mL of physiological solution per 25 kg every 12 hours. Higher total protein concentrations, hemoglobin levels, as well as increased aspartate aminotransferase activity and increased abomasal pH for up to 150 min following drug administration were observed in all animals that received the drug, regardless of dose and frequency. The animals treated every 12 hours showed a decrease in leukocyte number compared with the control group and with the animals treated every 8 hours. Increased serum creatinine concentrations were observed in the animals treated every 8 hours. Treatments of 1mg/kg every 8 hours and 2mg/kg every 12 hours increased the red blood cell count and decreased the serum pepsinogen. All protocols studied were safe for healthy sheep, but 1mg/kg ranitidine every 8 hours and 2mg/kg ranitidine every 12 hours were the most effective protocols for gastric protection.(AU)

A ovinocultura brasileira tem se intensificado, o que predispõe os animais à maior incidência de transtornos digestivos, como a úlcera de abomaso. A ranitidina é utilizada na prevenção e tratamento desta afecção, no entanto há pouca informação sobre a indicação parenteral deste fármaco para ruminantes adultos. São escassas as informações a respeito das alterações metabólicas e do comportamento do sistema digestório associados ao seu uso. Para este estudo foram utilizados cinco ovinos, machos, hígidos, providos de cânula ruminal e abomasal. O delineamento foi Quadrado Latino 5x5 com arranjo fatorial de tratamentos 2x2+1. Os ovinos tratados com as doses de 1 e 2mg/kg de ranitidina administrada por via intravenosa a cada 8 ou 12 horas foram comparados aos animais do grupo controle, tratados por via intravenosa com 1mL de solução fisiológica por 25 kg a cada 12 horas. Maiores concentrações de proteína total e hemoglobina, maiores atividades de AST e aumento do pH abomasal por até 150 minutos foram observados em todos os animais que receberam o fármaco, independentemente de dose e frequência. Os animais tratados a cada 12 horas mostraram diminuição do número de leucócitos comparados aos animais tratados a cada 8 horas e aos animais do grupo controle. Observou-se aumento das concentrações de creatinina nos animais tratados a cada 8 horas. Os tratamentos 1mg/kg a cada 8 horas e 2mg/kg a cada 12 horas aumentaram o número de hemácias e diminuíram as concentrações séricas de pepsinogênio. Todos os protocolos estudados foram seguros para ovinos sadios, porém 1mg/kg de ranitidina a cada 8 horas e 2mg/kg a cada 12 horas mostraram-se mais eficientes quanto à proteção gástrica.

Incidence of postoperative dyspepsia is not associated with prophylactic use of drugs / Incidência de dispepsia pós-operatória não está associada com uso profilático de medicamentos

CONTEXT AND OBJECTIVE: Preoperative fasting guidelines do not recommend H2 receptor antagonists or proton pump inhibitors. This study investigated prophylactic use of gastric protection and the incidence of dyspeptic symptoms in the immediate postoperative period. DESIGN AND SETTING: Non-randomized observational investigation in a post-anesthesia care unit. METHODS: American Society of Anesthesiologists risk classification ASAP1 and ASAP2 patients over 18 years of age were evaluated to identify dyspeptic symptoms during post-anesthesia care for up to 48 hours, after receiving or not receiving prophylactic gastric protection during anesthesia. History of dyspeptic symptoms and previous use of such medications were exclusion criteria. The odds ratio for incidence of dyspeptic symptoms with use of these medications was obtained. RESULTS: This investigation studied 188 patients: 71% women; 50.5% ASAP1 patients. Most patients received general anesthesia (68%). Gastric protection was widely used (n = 164; 87.2%), comprising omeprazole (n = 126; 76.8%) or ranitidine (n = 38; 23.2%). Only a few patients did not receive any prophylaxis (n = 24; 12.8%). During the observation, 24 patients (12.8%) reported some dyspeptic symptoms but without any relationship with prophylaxis (relative risk, RR = 0.56; 95% confidence interval, CI: 0.23-1.35; P = 0.17; number needed to treat, NNT = 11). Omeprazole, compared with ranitidine, did not reduce the chance of having symptoms (RR = 0.65; 95% CI: 0.27-1.60; P = 0.26; NNT = 19). CONCLUSION: This study suggests that prophylactic use of proton pump inhibitors or H2 receptor antagonists was routine for asymptomatic patients and was not associated with postoperative protection against dyspeptic symptoms. .

CONTEXTO E OBJETIVO: Diretrizes para jejum pré-operatório não recomendam antagonistas dos receptores H2 ou inibidores da bomba de prótons. Este estudo investigou o uso profilático de proteção gástrica e a incidência de sintomas dispépticos no período pós-operatório imediato. TIPO DE ESTUDO E LOCAL: Estudo observacional não aleatorizado em unidade de recuperação pós-anestésica. MÉTODOS: Pacientes ASAP1 e ASAP2, classificação de risco da American Society of Anesthesiologists, com mais de 18 anos de idade, foram avaliados para identificar sintomas dispépticos durante a recuperação pós-anestésica em até 48 horas, tendo ou não recebido proteção gástrica profilática durante a anestesia. História de sintomas dispépticos e uso prévio de tais medicamentos foram critérios de exclusão. A razão de chances para incidência de sintomas dispépticos com uso desses medicamentos foi obtida. RESULTADOS: Foram estudados 188 pacientes, 71% mulheres, 50,5% dos pacientes ASAP1. A maioria dos pacientes recebeu anestesia geral (68%). Proteção gástrica foi amplamente usada (n = 164; 87,2%), consistindo de omeprazol (n = 126; 76,8%) ou ranitidina (n = 38; 23,2%). Poucos pacientes não receberam qualquer profilaxia (n = 24; 12,8%). Durante a observação, 24 pacientes (12,8%) relataram alguns sintomas dispépticos, porém sem relação com profilaxia (risco relativo, RR = 0,56; intervalo de confiança, IC 95% 0,23-1,35, P = 0,17; número necessário para tratar, NNT = 11). Omeprazol, comparado à ranitidina, não reduziu a chance de ter sintomas (RR = 0,65; IC 95% 0,27-1,60; P = 0,26; NNT = 19). CONCLUSÃO: Este estudo sugere que o uso profilático de inibidores da bomba de prótons ...

Test of dissolution and comparison of in vitro dissolution profiles of coated ranitidine tablets marketed in Bahia, Brazil

Ranitidine is an antisecretory drug with H2 antagonist action useful in treating gastric and duodenal disorders. The dissolution test is used to obtain and compare dissolution profiles and establish similarities of pharmaceutical forms. The aim of this study was to compare the dissolution profiles of 150-mg coated ranitidine tablets of a reference drug (product A) and a generic (product B) and a similar (product C) drug marketed in Bahia, Brazil using a simple, fast and inexpensive ultraviolet method. Dissolution was determined using a USP type 2 apparatus at 50 rpm with 900 mL of distilled water at 37.0 ± 0.5 oC for 1h. The dissolution test was performed in compliance with the American Pharmacopoeia (USP-32). Dissolution efficiency and difference (f1) and similarity (f2) factors were calculated and evaluated. The proposed quantification methodology for drug dissolution test was validated, presenting accuracy, linearity and precision within the acceptance criteria. Products A, B and C showed dissolution efficiency values of 59.29, 73.59 and 66.67%, respectively. Factors f1 and f2 were calculated and showed that the profiles of products A, B and C were dissimilar. However, all the products released ranitidine satisfactorily, with at least 80% of the drug dissolved within 30 min.

A ranitidina é um fármaco antissecretor, antagonista H2, usado no tratamento de desordens gástricas e duodenais. O teste de dissolução é utilizado para obter e comparar perfis de dissolução, estabelecendo semelhança de formas farmacêuticas. Este estudo tem por objetivo comparar perfis de dissolução de comprimidos revestidos contendo 150 mg de ranitidina, em medicamentos de referência (produto A), genérico (produto B) e similar (produto C) comercializados na Bahia-Brasil, usando um método ultravioleta simples, rápido e de baixo custo. As condições que permitiram a determinação da dissolução foram: aparelho USP tipo 2 a 50 rpm, contendo 900 mL de água destilada mantida a 37,0 ± 0,5 °C, durante 1 h. O teste de dissolução foi realizado em conformidade com a Farmacopeia Americana (USP-32). Cálculo da eficiência de dissolução e fatores de diferença (f1) e semelhança (f2) foram avaliados. A metodologia proposta para a quantificação do fármaco no ensaio de dissolução foi validada apresentando precisão, linearidade e exatidão dentro dos critérios de aceitação. Os produtos A, B e C mostraram eficiência de dissolução de 59,29, 73,59 e 66,67%, respectivamente. Calcularam-se os fatores f1 e f2 e mostrou-se que os perfis não foram semelhantes para os comprimidos de produtos A, B e C. No entanto, todos os produtos liberaram o fármaco satisfatoriamente, pois, pelo menos, 80% de ranitidina foram dissolvidos em 30 min.

Effect of histamine H1 and H2 receptor antagonists, microinjected into cerebellar vermis, on emotional memory consolidation in mice

This study investigated the effects of histamine H1 or H2 receptor antagonists on emotional memory consolidation in mice submitted to the elevated plus maze (EPM). The cerebellar vermis of male mice (Swiss albino) was implanted using a cannula guide. Three days after recovery, behavioral tests were performed in the EPM on 2 consecutive days (T1 and T2). Immediately after exposure to the EPM (T1), animals received a microinjection of saline (SAL) or the H1 antagonist chlorpheniramine (CPA; 0.016, 0.052, or 0.16 nmol/0.1 µL) in Experiment 1, and SAL or the H2 antagonist ranitidine (RA; 0.57, 2.85, or 5.7 nmol/0.1 µL) in Experiment 2. Twenty-four hours later, mice were reexposed to the EPM (T2) under the same experimental conditions but they did not receive any injection. Data were analyzed using one-way ANOVA and the Duncan test. In Experiment 1, mice microinjected with SAL and with CPA entered the open arms less often (%OAE) and spent less time in the open arms (%OAT) in T2, and there was no difference among groups. The results of Experiment 2 demonstrated that the values of %OAE and %OAT in T2 were lower compared to T1 for the groups that were microinjected with SAL and 2.85 nmol/0.1 µL RA. However, when animals were microinjected with 5.7 nmol/0.1 µL RA, they did not show a reduction in %OAE and %OAT. These results demonstrate that CPA did not affect behavior at the doses used in this study, while 5.7 nmol/0.1 µL RA induced impairment of memory consolidation in the EPM.

Determinación de clorhidrato de ranitidina por cromatografía líquida de alta resolución en una solución inyectable / Ranitidine hydrochloride assay by high resolution liquid chromatography in an injectable solution

En la Farmacopea de los Estados Unidos se orienta como valorar el clorhidrato de ranitidina en una solución inyectable pero cuando se intentó reproducir esta monografía, la ranitidina no se adsorbió a una columna similar a la recomendada. El objetivo del presente trabajo fue validar un método alternativo para la cuantificación de clorhidrato de ranitidina en una solución inyectable. El método alternativo empleado fue el descrito en la Farmacopea de los Estados Unidos para la cuantificación del clorhidrato de ranitidina (la sustancia activa), con modificaciones. La validación del método se realizó siguiendo las indicaciones de la Guía Q2(R1) de la Conferencia Internacional sobre la Armonización. Además se determinó la incertidumbre del método. Los coeficientes de variación obtenidos para la precisión intermedia fueron inferiores a 1,0 %; en la exactitud el recobrado fue de 100,30 % y en la linealidad se demostró la ausencia de curvatura en el intervalo 80 a 120 %. La incertidumbre expandida calculada fue inferior al 2 % de la concentración presente en las muestras. Todos los parámetros de validación evaluados se encontraron dentro los límites de aceptación establecidos por lo que se concluye que el método es adecuado para los fines propuestos.

The United States Pharmacopeia instructs for the determination of ranitidine hydrochloride in an injectable solution but when we tried to reproduce this monograph, the ranitidine was not adsorbed in a similar column as the recommended. The aim of the present work was to validate an alternate method for the determination of ranitidine hydrochloride in an injectable solution. The alternate method was the one described in the United States Pharmacopeia for the determination of ranitidine hydrochloride (active pharmaceutical ingredient), with modifications. The method was validated as per Q2(R1) Guideline, of the International Conference on Harmonization. Method´s uncertainty was also determined. The coefficient of variation obtained for intermediate precision was less than 1.0 %; in the accuracy, the recovery was 100.30 % and the linearity showed absence of curvature in the range of 80 to 120 %. The expanded uncertainty calculated was less than 2 % of the amounts in the samples. All validation parameters evaluated were within acceptation limits established, therefore it is concluded that the method is suitable for the intended purposes.