Modulatory effects of taurine on jejunal contractility

Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

H[2] receptor activity; effect in isolated rabbit heart

Histamine can stimulate the heart by directly interacting with cardiac histamine receptors. In the present study we have investigated the H[2] receptor activity in isolated rabbit heart. Cimetidine, a specific H[2] receptor antagonist was used. The isolated heart was mounted in langendroff apparatus. The heart was perfused at a constant pressure with oxygenated Ringer's Locke solution. H[2] receptor antagonist produces negative inotropic effect in the presence of histamine. This indicates that H[2] receptors are present in rabbit heart, and plays a role in mediation of positive inotropic effect produced through CAMP by histamine

Avaliação da atividade protetora gástrica do extrato hidroalcoólico da semente de girassol / Evaluation of the gastroprotective activity of the hydroalcoholic extract of sunflower seeds

JUSTIFICATIVA E OBJETIVOS: Avaliar quantitativa e qualitativamente a provável proteção gástrica do extrato hidroalcoólico da semente de girassol (EHSG) em relação ao estresse, ao uso de indometacina e etanol; bem como verificar a acidez (pH) gástrica por meio da ligadura pilórica (resíduo gástrico puro e com adição de água) e comparar as diferenças dos valores do pH em ambos os modelos. MÉTODO: Foram estudados 120 ratos (5 em cada grupo) da espécie Rattus norvegicus albinus, com peso de 150-230g, divididos em 24 grupos distintos, os quais receberam os seguintes tratamentos: EHSG: 250 mg/kg, 500 mg/kg, 1000 mg/kg e 2000 mg/kg; etanol 0,5 mL; cimetidina 60 mg/kg; indometacina 20 mg/kg; água 1 mL; ligadura de piloro (água; cimetidina e EHSG). Os dados foram analisados utilizando o programa Grand Pad Prism 5 com aplicação de testes estatísticos considerando o nível de significância de 5%.RESULTADOS: O EHSG nas doses 250 e 1000 mg/kg sugeriu proteção contra as lesões gástricas no estresse. No modelo de indução de úlcera gástrica por etanol, as doses de 250 e 1000 mg/kg apresentaram provável proteção gástrica. No grupo utilizando EHSG 250 mg/kg e indometacina a dose de 250 mg/kg também sugere proteção gástrica. Em relação ao valor de pH, o resíduo gástrico, quando verificado puro, é mais ácido que pelo modelo da adição da água, significando que este último modelo está aumentando o pH, comprovando assim que o modelo do resíduo gástrico puro é mais indicado e prático. CONCLUSÃO: Os dados obtidos no presente estudo mostram que o EHSG apresenta provável proteção gástrica em determinadas doses.(AU)

BACKGROUND AND OBJECTIVES: To evaluate quantitatively and qualitatively the probable gastric protection of hydroalcoholic extract from sunflower seed (EHSG) in relation to stress, the use of indomethacin and ethanol; check the acidity (pH) through the gastric pylorus ligation (gastric residue pure and with added water), and compare differences in pH values in both models. METHOD: A total of 120 rats (5 in each group) of the type Wistar rats weighing 150-230g were divided into 24 distinct groups, which received the following treatments: EHSG: 250 mg/kg, 500 mg/kg, 1000 mg/kg and 2000 mg/kg, 0.5 mL ethanol, cimetidine 60 mg/kg, indomethacin 20 mg/kg, 1 mL water, ligation of pylorus (water, cimetidine and EHSG). The data were analyzed using the Grand Pad Prism 5 with application of statistical tests considering the significance level of 5%.RESULTS: The EHSG at doses 250 and 1000 mg/kg suggested protection against gastric lesions in stress. In the model of gastric ulcer induced by ethanol, the doses of 250 and 1000 mg/kg showed probable gastric protection. Group using EHSG 250 mg/kg and indomethacin dose of 250 mg/kg also suggests gastric protection. Regarding the pH, the gastric residue, occurred when pure, is more acidic than the model of the addition of water, meaning that the latter model is increasing the pH, thus proving that the model of pure gastric residue is more appropriate and more practical. CONCLUSION: The data obtained in this study show that has likely EHSG gastric protection in certain doses.(AU)

Efeitos hemodinâmicos do atracúrio e do cisatracúrio e o uso de difenidramina e cimetidina / Hemodynamic effects of atracurium and cisatracurium and the use of diphenhydramine and cimetidine / Efectos hemodinámicos del atracurio y del cisatracurio y el uso de la difenidramina y la cimetidina

Justificativa e objetivos: Haja visto que atracúrio pode causar hipotensão arterial no homem, investigaram-se os efeitos hemodinâmicos promovidos pelo atracúrio e pelo cisatracúrio e a proteção hemodinâmica conferida pela difenidramina e cimetidina em ratos. Método: 1) Ratos Wistar anestesiados com pentobarbital sódico e preparados de acordo com Brown e col. para avaliar doses de atracúrio e cisatracúrio para redução de T4/T1 da sequência de quatro estímulos maior ou igual a 95 por cento. 2) Avaliação das alterações hemodinâmicas de atracúrio e cisatracúrio por injeção venosa, medindo-se a pressão arterial sistêmica da artéria carótida e eletrocardiograma de ratos. 3) Observação de proteção hemodinâmica pelo tratamento prévio com difenidramina (2 mg.kg-1) e/ou cimetidina (4 mg.kg-1) por injeção venosa. Análise estatística: teste t de Student, ANOVA. Resultados: O atracúrio e o cisatracúrio não modificaram a pressão arterial média (PAM) nas doses de 1 mg.kg-1 e 0,25 mg.kg-1, respectivamente. Doses de 4 mg.kg-1 promoveram diminuição da PAM de 62,8 ± 4,5 por cento do controle para o atracúrio, e de 82,5 ± 2,3 por cento do controle para o cisatracúrio. Com difenidramina e cimetidina, a pressão sistólica diminuiu 95,4 ± 2,5 por cento do controle. Com cimetidina, pressão diastólica diminuiu 82,7 ± 8,4 por cento do controle. O efeito conjunto sobre as pressões sistólica e diastólica refletiu-se nos valores observados da PAM. Conclusões: A difenidramina e a cimetidina, isoladamente, não impediram a diminuição da pressão arterial média induzida pelo atracúrio. No entanto, associação destes dois fármacos foi eficaz na prevenção dos efeitos hemodinâmicos induzidos pelo atracúrio. O cisatracúrio nas doses do experimento não promoveu diminuição da pressão arterial que justificasse as medidas preventivas aplicadas nos grupos onde se utilizou o atracúrio.

Background and objectives: Since atracurium can cause hypotension in humans, the hemodynamic effects of atracurium and cisatracurium as well as the hemodynamic protection of diphenhydramine and cimetidine were investigated in rats. Methods: 1) Wistar rats were anesthetized with sodium pentobarbital and prepared according to Brown et al. to evaluate different doses of atracurium and cisatracurium in the reduction of T4/T1 equal or greater than 95 percent. 2) Assessment of the hemodynamic changes caused by the intravenous administration of atracurium and cisatracurium by monitoring the blood pressure in the carotid artery and the electrocardiogram of rats. 3) Observation of the hemodynamic protection of prior treatment with the intravenous administration of diphenhydramine (2 mg.kg-1) and/or cimetidine (4 mg.kg-1). Statistical analysis: Student t test and ANOVA. Results: Doses of 1 mg.kg-1 and 0.25 mg.kg-1 of atracurium and cisatracurium respectively did not change the mean arterial pressure (MAP). Doses of 4 mg.kg-1 of atracurium and cisatracurium decreased MAP to 62.8 ± 4.5 percent and 82.5 ± 2.3 percent respectively when compared to control levels. When the rats were pre-treated with diphenhydramine and cimetidine, diastolic pressure was reduced to 95.4 percent ± 2.5 percent. With cimetidine, diastolic pressure was reduced to 82.7 ± 8.4 percent when compared to the control group. The effects on systolic and diastolic blood pressure were reflected in the levels of MAP. Conclusions: The isolated administration of diphenhydramine and cimetidine did not prevent the reduction in mean arterial pressure induced by atracurium. However, the association of both drugs was able to prevent the hemodynamic effects of atracurium. The doses of cisatracurium used in this study did not cause a reduction in blood pressure significant enough to justify the use of the preventive measures used in the atracurium groups.

Justificativa y objetivos: Habida cuenta de que el atracurio puede causar hipotensión arterial en el hombre, se investigaron los efectos hemodinámicos promovidos por el atracurio y por el cisatracurio, y la protección hemodinámica dada por la difenidramina y la cimetidina en ratones. Método: 1) Ratones Wistar anestesiados con pentobarbital sódico y preparados de acuerdo con Brown y col. para evaluar las dosis de atracurio y cisatracurio para la reducción de T4/T1 de la secuencia de cuatro estímulos mayor o igual al 95 por ciento. 2) Evaluación de las alteraciones hemodinámicas del atracurio y el cisatracurio por inyección venosa, midiendo la presión arterial sistémica de la arteria carótida y electrocardiograma de ratones. 3) Observación de la protección hemodinámica por el tratamiento previo con difenidramina (2 mg.kg-1) y/o cimetidina (4 mg.kg-1) por inyección venosa. Análisis estadístico: test t de Student, ANOVA. Resultados: El atracurio y el cisatracurio no modificaron la presión arterial promedio (PAP) en las dosis de 1 mg.kg-1 y 0,25 mg.kg-1, respectivamente. Las dosis de 4 mg.kg-1 disminuyeron la PAP de 62,8 ± 4,5 por ciento del control para el atracurio, y de 82,5 ± 2,3 por ciento del control para el cisatracurio. Con la difenidramina y la cimetidina, la presión sistólica se redujo a 95,4 ± 2,5 por ciento del control. Con la cimetidina, la presión diastólica disminuyó 82,7 ± 8,4 por ciento del control. El efecto con-junto sobre las presiones sistólica y diastólica se reflejó en los valores observados de la PAP. Conclusiones: La difenidramina y la cimetidina, aisladamente, no impidieron la disminución de la presión arterial promedio inducida por el atracurio. Sin embargo, la asociación de esos de los fármacos fue eficaz en la prevención de los efectos hemodinámicos inducidos por el atracurio. El cisatracurio, en las dosis del experimento, no promovió una disminución de la presión arterial que justificase las medidas preventivas...

Hepatoprotective effect of tocopherol against isoniazid and rifampicin induced hepatotoxicity in albino rabbits.

Antitubercular drug induced hepatotoxicity is a major hurdle for an effective treatment of tuberculosis. The present study was undertaken to assess the hepatoprotective potential of tocopherol (50 mg/kg and 100 mg/kg, ip) and to compare it with cimetidine (120 mg/kg, ip). Hepatotoxicity was produced by giving isoniazid (INH, 50 mg/kg, po) and rifampicin (RMP, 100 mg/kg, po) combination to albino rabbits for 7 days. Assessment of liver injury was done by estimating levels of alanine transaminase (ALT) and argininosuccinic acid lyase (ASAL) in serum and by histopathological examination of liver. Results revealed that pretreatment with high dose of tocopherol (100 mg/kg) prevented both biochemical as well as histopathological evidence of hepatic damage induced by INH and RMP combination. Moreover, tocopherol (100 mg/kg) was found to be a more effective hepatoprotective agent as compared to cimetidine.

Effect of cimetidine on hepatotoxicity induced by isoniazid-rifampicin combination in rabbits.

OBJECTIVE: To evaluate the hepatoprotective potential of cimetidine in hepatotoxicity induced by isoniazid-rifampicin combination in albino rabbits. METHODS: Six groups of six rabbits each were studied. Three groups received saline (control), isoniazid (50 mg/Kg/d) alone or isoniazid with rifampicin (100 mg/Kg/d) daily orally for 7 days. Other groups received intraperitoneal cimetidine (50 mg/Kg/d) alone or cimetidine (50 or 120 mg/Kg/d) along with isoniazid-rifampicin combination. Serum levels of liver enzymes were measured at baseline and on day 8 and liver histology was studied on day 8. RESULTS: Rabbits receiving isoniazid alone for 7 days showed no increase in serum ALT and AST levels, whereas those receiving isoniazid-rifampicin combination had a 3-4-fold increase in these levels (p=0.02). Animals receiving cimetidine pre-treatment did not show a significant increase in ALT and AST levels. Histological changes in the liver were more common with isoniazid-rifampicin combination than with isoniazid only. These changes were reduced in animals receiving low-dose cimetidine and prevented in those receiving high-dose cimetidine. CONCLUSION: Cimetidine in high dose can prevent hepatotoxicity induced by isoniazid-rifampicin combination.

Serum concentration of testosterone, epididymal mast cell population and histamine content in relation to sperm count and their motility in albino rats following H2 receptor blocker treatment.

H2 receptor blocker treatment over a period of 2 weeks had been found to cause significant reduction in epididymal tissue mast cell population and tissue histamine content in caput, corpus and cauda regions in albino rats. There was also a highly significant fall of serum testosterone level and sperm count in these segmental fluids collected by micropuncture. The motility of sperms was also greatly reduced and the number of abnormal spermatozoa was found to be increased, the increase being highly significant in the caudal segment. In view of histamine being involved in steroidogenic activity, it appears that reduction in epididymal tissue histamine content following H2 receptor blocker treatment had caused low availability of testosterone to the tissues and thereby the reduction in sperm count and their motility. Increase in number of abnormal sperms particularly in the caudal epididymis is likely to be due to malformation and increased destruction of sperms, because of alteration in epididymal environment due to fall in serum testosterone concentration.

Resposta cronotrópica ao teste cardiopulmonar após o uso de cimetidina / Effects of cimetidine on chronotropic response to cardiopulmonary exercise testing

OBJETIVO: Testar a hipótese, por meio de ensaio clínico randomizado, de que a administração de cimetidina altera a resposta cronotrópica ao exercício. MÉTODOS: Foram selecionados 24 indivíduos saudáveis, com idade entre 20 e 68 anos, não-atletas, os quais concordaram em ser submetidos a testes cardiopulmonares, após uso de placebo e de cimetidina, 400 mg, duas vezes ao dia, durante uma semana. Os testes foram realizados em esteira rolante, com protocolo de rampa com análises diretas dos gases expirados. Foi avaliada freqüência cardíaca máxima atingida, além da freqüência cardíaca de repouso e do limiar anaeróbico. RESULTADOS: Os indivíduos estudados foram igualmente distribuídos por sexo, com idade média (± desvio padrão) de 43 ±11 anos. Os exames com placebo e com cimetidina tiveram igual duração (578±90 seg vs 603±131 seg) e igual VO2 pico (35±8 ml/kg.min vs 35±8 ml/kg.min). A administração de cimetidina não apresentou efeito significativo na freqüência cardíaca de repouso (75±10 vs 74±8 bpm), no pico do esforço (176±12 vs 176±11 bpm) e, da mesma forma, também não houve diferença entre as variações das freqüências cardíacas (pico - repouso), nos dois estudos (101±14 vs 101±13 bpm). CONCLUSÃO: A administração de cimetidina por sete dias não altera a resposta cronotrópica ao exercício.

Inhibition of tryptase release from human colon mast cells by histamine receptor antagonists.

The main objective of this study was to investigate the ability of histamine receptor antagonists to modulate tryptase release from human colon mast cells induced by histamine. Enzymatically dispersed cells from human colon were challenged with histamine in the absence or presence of the histamine receptor antagonists, and the tryptase release was determined. It was found that histamine induced tryptase release from colon mast cells was inhibited by up to approximately 61.5% and 24% by the H1 histamine receptor antagonist terfenadine and the H2 histamine receptor antagonist cimetidine, respectively, when histamine and its antagonists were added to cells at the same time. The H3 histamine receptor antagonist clobenpropit had no effect on histamine induced tryptase release from colon mast cells at all concentrations tested. Preincubation of terfenadine, cimetidine or clobenpropit with cells for 20 minutes before challenging with histamine did not enhance the ability of these antihistamines to inhibit histamine induced tryptase release. Apart from terfenadine at 100 microg/ml, the antagonists themselves did not stimulate tryptase release from colon mast cells following both 15 minutes and 35 minutes incubation periods. It was concluded that H1 and H2 histamine receptor antagonists were able to inhibit histamine induced tryptase release from colon mast cells. This not only added some new data to our hypothesis of self-amplification mechanisms of mast cell degranulation, but also suggested that combining these two types of antihistamine drugs could be useful for the treatment of inflammatory bowel disease (IBD).

Effects of anti-allergic drugs on intestinal mastocytosis and worm expulsion of rats infected with Neodiplostomum seoulense

The effects of anti-allergic drugs on intestinal mastocytosis and the expulsion of Neodiplostomum seoulense were observed in Sprague-Dawley rats, after oral infection with 500 metacercariae. The drugs used were hydroxyzine (a histamine receptor H1 blocker), cimetidine (a H2 blocker), cyclosporin-A (a helper T-cell suppressant), and prednisolone (a T- and B-cell suppressant). Infected, but untreated controls, and uninfected controls, were prepared. Worm recovery rate and intestinal mastocytosis were measured on weeks 1, 2, 3, 5, and 7 post-infection. Compared with the infected controls, worm expulsion was significantly (P < 0.05) delayed in hydroxyzine- and cimetidine-treated rats, despite mastocytosis being equally marked in the duodenum of all three groups. In the cyclosporin-A- and prednisolone-treated groups, mastocytosis was suppressed, but worm expulsion was only slightly delayed, without statistical significance. Our results suggest that binding of histamine to its receptors on intestinal smooth muscles is more important in terms of the expulsion of N. seoulense from rats than the levels of histamine alone, or mastocytosis.

Morphogenesis of testes: Effect of perinatal exposure to maternally administered cimetidine

Perinatal androgens are essential for normal masculine imprinting, whereas cimetidine, a widely prescribed H[2] antagonist, is a mild antiandrogen. To assess the role of maternally administered cimetidine on the development of testes. MATERIAL AND METHODS: Male albino mice were perinatally exposed to cimetidine during late gestation and early neonatal life, while control group animals were given equivalent amount of distilled water. The cimetidine exposed male progeny, sacrificed on 8th and 56th postnatal day, when observed for gross parameters and histological profile, confirmed the maldevelopment and testicular atrophy, which persisted into adult life. it is concluded that widespread and indiscriminate use of cimetidine causes threat to human beings, therefore it should be used with caution in pregnant women, especially during the critical period of differentiation of gonads

study of the effect of H1-and H2-receptor blocking drugs on the normal healing process of excised skin wounds in the rat

In this study, 240 adult healthy albino rats of both sexes were used. They were classified into control and drug-treated groups. Full thickness excised skin wounds were inflicted on the shaved dorsal aspect of the thoracic wall. The mean healing time, rate of wound contraction, the total and the saline soluble collagen concentrations in the healing wound area were measured. Loratadine did not significantly alter any of the wound healing parameters studied. Cimetidine has caused a statistically significant shortening of the mean healing time, acceleration of wound contraction rate, reduction of the total and increase in the saline soluble collagen concentration in the healing wound area 2 and 3 weeks post-wounding

Comparison of antiulcer effects of tricyclic antidepressants with cimetidine and omprazole in rats

The antiulcer effects of different tricyclic antidepressants [trimipramine, doxepin, imipramine, and amitriptyline] in comparison with those of cimetidine, pirenzepine and omeprazole were investigated in male rats with acute gastric ulcer. Acute gastric ulcer was induced by oral administration of 0.6N HCI solution, 1 mL/rat. Pretreatment of animals with doxepin, trimipramine, amitriptyline, imipramine [in doses of 10,25,40, 50, and 75 mg/kg, SC], cimetidine [in doses of 50, 75, 100, 150 and 200 mg/kg, SC], omeprazole and pirenzepine [in doses of 10, 20, 30,40 and 50 mg/kg, SC] inhibited the formation of erosions dose-dependently. The ED [50] of these agents revealed that the most active agents were omeprazole, doxepin and pirenzepine, followed by trimipramine and cimetidine. Imipramine and amitriptyline had slight antiulcer activity

Prevención de la náusea y vómito postoperatorio en rinoseptoplastía / Postoperative nausea and vomiting prevention in nose surgery

Se estudiaron 120 pacientes, todos sanos, de ambos sexos, sometidos a cirugía de Rinoseptoplastias, divididos en dos grupos. Al grupo A se le administraron 10 mg de Metoclopramida IV. Al grupo B se le administraron 10 mg de Metoclopramida, más 300 mg de Cimetidina IV. Ambos fármacos durante la inducción, valorando únicamente los efectos más indeseables después de una anestesia, como son las náuseas y los vómitos postoperatorios (NVPO). Todos los pacientes se manejaron en forma idéntica, tanto en la medicación preanestésica, inducción, mantenimiento, manejo quirúrgico y postoperatorio. El control de los mismos se llevó a cabo durante 24 horas que permanecieron hospitalizados. No se apreciaron efectos adversos durante el uso de estos medicamentos. Por los resultados obtenidos, se sugiere la combinación de la Metoclopramida y Cimetidina

"In vivo" and "in vitro" antitumoral action of Larrea divaricata cav

We previously reported that aqueous extract of Larrea divaricata Cav had an antiproliferative activity upon tumoral lymphoid cells (BW 5147), without affecting normal immunity. To determine the probable mechanism of the inhibitory action of the extract upon cell growth, the participation of intracellular signals involved in the inhibition of cell proliferation, namely the activation of adenylate cyclase system was studied. The production of cyclic 3', 5 adenosine monophosphate (cAMP) in presence and absence of extract was analized. The extract increased the cAMP levels, but neither the cAMP production nor the inhibitory effect of the extract on proliferation were blocked by a beta adrenergic receptor antagonist (propranolol) or by histaminergic receptor antagonistis (cimetidine and mepyramine). So, we concluted that the antiproliferative activity of the extract of BW 5147 cells would be mediated by an increase in cAMP intracellular levels no related to the activation of the membrane receptors here studied. In parallel, the extract was administered to a pregnant rat with a spontaneous mammarian carcinoma and "in vivo"antitumoral activity was found.

Effects of cimetidine, ranitidine and tiotidine on spermatogenesis in albino rats

The effects of cimetidine, ranitidine and tiotidine were studied on spermatogenesis in adult male albino rats after administering these drugs at the dose levels of 5.71 mg/ kg, 2.14 mg/kg and 1.42 mg/kg body weight respectively twice daily for a period of five weeks. The results showed that cimetidine and tiotidine caused a significant decrease [P < 0.05] in the number of spermatocytes. However cimetidine and tiotidine produced a marked decrease [P < 0.05] and [P < 0.001] respectively, in the number of total germ cells in the seminiferous tubules. It is conceivable that ranitidine also possess antispermatogenic activity which was not found out in previous research work

Effects cimetidine ranitidine and tiotidine on plasma testosterone and luteinizing hormone level in rats

The investigation was carried out to study the comparative effects of cimetidine, ranitidine and tiotidine on the plasma levels of testosterone and luteinizing hormone under local environmental conditions. The three H2- blocking drugs were injected to the adult male albino rats twice daily at the recommended therapeutic dose levels for six weeks. The data obtained showed that only tiotidine caused a significant [P< 0.05] increase in the level of testosterone. However, all the three drugs caused a significant rise in the levels of luteinizing hormone and maximum with ranitidine

Effect of cimetidine on weight gain in rats.

Effect on food intake and body weight was studied in rats after oral administration of cimetidine. Rats in experimental (E) group exhibited less increase in food intake (20%) compared to control (C) rats (43.8%). Mean body weight showed first reduction (-9.56%) and then very small increment in experimental animals compared to gradual gain in body weight in control animals. At the end of 6 weeks, total gain in body weight was 22.5 gm in rats of E group against 53.8 gm in rats of C group. Food efficiency ratio (FER) showed much reduction (1.13) in E group against 2.07 in C group. These results demonstrate that cimetidine (H2-receptor blocker) may have ability to reduce food intake and body weight in rats.

Comparative bioavailability of three commercially available cimetidine tablet formulations in healthy male volunteers

This investigation was carried out to evaluate the relative bioavailability of two different marketed 400 mg cimetidine tablets [cimedine' and citius'] compared to the innovator product [Tagamet, 400 mg tablet]. The three brands were found to be similar in assay average weight, weight uniformity, disintegration time and dissolution tests as specified in the USP XXII. The bioequivalency study was carried out on twelve healthy male volunteers who received a single oral dose [400 mg tablet] of each of the three formulations in the fasting state, in a randomized balanced three way crossover design. After dosing, serial blood samples were collected for a period of 8 hours. Cimetidine plasma concentrations were determined using a sensitive and validated high-performance liquid chromatographic [HPLC] assay. The maximum plasma concentration [Cmax] time to maximum concentration [Tmax] area under the plasma concentration time curve up to the last measurable concentration [AUCO-T], and to infinity [AUCO-OO], the elimination rate constant [Kel] and elimination halflife [t1/2] were analyzed statistically using analysis of variance [ANOVA] and the least significant difference [LSD] method. No statistically significant differences were found between the three brands in any of the calculated parameters. Therefore, the three formulations are considered bioequivalent