Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new zelmac research articles will be listed here shortly after becoming available to us.
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Medical research on zelmac
J Pharmacol Sci. 2008 Jun 28;
Mikami T, Sugimoto H, Naganeo R, Ohmi T, Saito T, Eda H
In the present study, binding affinities of 5-hydroxytryptamine-4 (5-HT(4)) ligands for the human 5-HT(4d) receptor were determined using the agonist [(3)H]5-HT and the selective 5-HT(4) antagonist [(3)H]GR113,808. We also compared the affinity differences between [(3)H]5-HT binding (K(H)) and [(3)H]GR113,808 binding (K(L)) with their activities as 5-HT(4) ligands. Binding studies using [(3)H]5-HT revealed that the human 5-HT(4d) receptor has two binding sites, whereas [(3)H]GR113,808 yielded a single binding site. Additionally, the number of [(3)H]5-HT binding sites decreased in the presence of guanosine-5'-O-(3-thiotriphosphate) (GTPgammaS), but the number of [(3)H]GR113,808 sites did not change. In competitive binding assays, full agonists such as 5-methoxytryptamine and tegaserod showed 2- to 8-fold higher affinities for [(3)H]5-HT binding (K(H)) than for [(3)H]GR113,808 binding (K(L)) (K(H)K(L)). Finally, partial agonists displayed similar binding affinities for both radioligands (K(H) = K(L)). These findings suggest that the equilibrium between active and inactive states of the human 5-HT(4d) receptor relies on the functional activities of 5-HT(4) ligands, and these states affect the affinities of 5-HT(4) ligands in the competitive binding assay.
Curr Med Res Opin. 2008 Jun 17;
Jr PB, Rodriguez-Stanley S, Proskin HM, Kianifard F, Bottoli I
BACKGROUND: While functional heartburn (FH) and functional dyspepsia (FD) are recognized clinical entities, symptoms often overlap across both disorders. Despite their frequency, little is known of the underlying pathophysiology of overlapping symptoms. This study evaluated the effect of the 5-HT(4) agonist, tegaserod, on visceral sensitivity and symptom improvement in patients with overlapping symptoms of FH and FD.RESEARCH DESIGN AND METHODS: Patients with overlapping symptoms of FH and FD (ROME II) and mechanical hypersensitivity (Barostat examination) were randomized to tegaserod 6 mg bid or placebo for 2 weeks with treatment crossover after a 2-week washout period. Esophageal and gastric Barostat sensory tests were performed and patients rated their overall symptoms at study end. When carry-over was detected, data were presented for period 1 only. Safety was also assessed.RESULTS: Sixty patients were screened of whom 30 were randomized and 25 completed. Mechanical hypersensitivity was reported by 83% of 47 patients completing esophageal and gastric baseline Barostat examinations. Tegaserod did not significantly alter balloon volume to pain (primary variable); however, pressure to gastric pain increased (p = 0.044 vs. placebo). The severity of heartburn, regurgitation, early fullness, and bloating was significantly lower following tegaserod vs. placebo treatment (p = 0.026, p = 0.021, p = 0.016, and p = 0.030). Overall symptom improvement was reported by 52% tegaserod vs. 32% placebo patients (p = 0.275), and treatment was well tolerated.CONCLUSIONS: Results suggest that tegaserod may increase the gastric pain threshold and decrease the severity of individual symptoms in patients with overlapping FH and FD. However, these findings must be considered within the context of the study limitations, including the small number of subjects, potential for and presence of a carry-over effect, along with the impact of Barostat balloon use on the assessment of gastric function.
Gastrointest Endosc. 2008 May 27;
Abdul-Baki H, Hashash JG, Elhajj II, Azar C, El Zahabi L, Mourad FH, Barada KA, Sharara AI
BACKGROUND: Problems of compliance, quality, and safety of colon preparation regimens have prompted continued investigation with alternative forms of cleansing. OBJECTIVE: To evaluate the efficacy of tegaserod as an adjunct to a polyethylene glycol electrolyte solution (PEG-E), given as a whole dose or split dose, in colonoscopy preparation. DESIGN: Randomized, placebo-controlled, double-blind trial. SETTING: A single university-based hospital. PATIENTS: Patients who were undergoing elective colonoscopy. INTERVENTIONS: A 4-arm randomization scheme that compared tegaserod with a placebo, each with whole-dose or split-dose PEG-E preparation. MAIN OUTCOME MEASUREMENTS: Efficacy of colon cleansing was the primary outcome. Secondary outcomes included adherence, tolerability, adverse effects, and patient perceptions of their preparation quality. RESULTS: A total of 382 patients completed the trial. Patients who received the split-dose preparation had significantly better colon cleansing than those who received the whole-dose preparation (88.9% vs 42.6%, P < .001). The addition of tegaserod did not significantly improve the overall colonoscopy preparation quality compared with a placebo. However, there were fewer poor preparations in the whole-dose PEG-E group (12.4% vs 1.1%, P = .002, Bonferroni correction removes significance) and more excellent preparations in the split-dose group (53.3% vs 38.3%, P = .035, Bonferroni correction removes significance) in favor of tegaserod. Interobserver and intraobserver variability analysis showed substantial agreement among endoscopists. Adherence was significantly lower in the whole-dose group versus the split-dose PEG-E group (68.8% vs 91%, P < .001), independent of the use of tegaserod. Adverse effects were not different between study groups. LIMITATIONS: A 4-arm randomization and the single-center nature of the study. CONCLUSIONS: Tegaserod has a marginal effect on the quality of colonoscopy preparation when used as an adjuvant to PEG-E. The split-dose PEG-E was superior to the whole-dose PEG-E and resulted in better colon cleansing, adherence, and tolerance.
The FDA's decision-making process: isn't it time to temper the principle of protective paternalism?
Am J Gastroenterol. 2008 May; 103(5): 1226-7
Brandt LJ
The authors conducted a well-designed, multinational, large study of women younger than 65 yr of age with irritable bowel syndrome (IBS) with a mixed pattern of diarrhea and constipation (IBS-M) or constipation (IBS-C) and showed that a statistically greater percentage of patients in each group responded to tegaserod compared with patients treated with placebo. Practicality looms large, however, in that the Food and Drug Administration (FDA) disallowed the continued marketing of tegaserod because of cardiovascular safety concerns, and it now is only available under a restricted access program. The wisdom of this decision aside, it is disturbing that the FDA revealed a zero-tolerance for any significant risk of disease when a drug (e.g., tegaserod) was used for a nonlife-threatening condition; the FDA chose to neglect any potential benefit of significant improvement in quality of life, while at the same time allowing the continued availability of sildenifil for erectile dysfunction and other medications (e.g., rosiglitazone and nonsteroidal anti-inflammatory drugs [NSAIDs]), each with a far greater risk of cardiovascular complications. Whether tegaserod will be re-released and, if so, under what conditions, is yet to be determined, as is the question of whether the FDA will decide to allow a more transparent decision-making process with input from all interested parties affected by their decision.
Am J Gastroenterol. 2008 May; 103(5): 1217-25
Chey WD, Paré P, Viegas A, Ligozio G, Shetzline MA
OBJECTIVES: Though the greatest proportion of irritable bowel syndrome (IBS) patients report a mixed bowel pattern (IBS-Mixed), no available therapies have been rigorously evaluated in this subgroup. This study aimed to evaluate the efficacy and safety of the 5-HT(4) agonist tegaserod in women with IBS-Mixed and IBS with constipation (IBS-C). METHODS: This prospective, double-blind, randomized, placebo-controlled, multicenter study was conducted in 100 centers in North America, South America, and Europe. Women with IBS-Mixed or IBS-C received tegaserod 6 mg or placebo twice daily. The primary efficacy variable was the patient's assessment of satisfactory relief over the 4-wk treatment period. The proportion of patients reporting satisfactory relief for >/=3 of 4 treatment weeks (75% rule) and individual IBS symptoms were assessed. RESULTS: In total, 661 women were randomized (IBS-Mixed 324, IBS-C 337). Baseline symptom assessments identified clear differences between the two cohorts. Tegaserod provided significant improvement in satisfactory relief of IBS symptoms over 4 wk (OR 1.75, 95% CI 1.35-2.25, P < 0.001) in both IBS-Mixed and IBS-C patients. Using the 75% rule, 52.3% of tegaserod-receiving IBS-M patients and 43.3% of IBS-C patients were responders (vs 36.3, OR 1.88, 95% CI 1.16-3.04, P < 0.010; and 28.9, OR 1.90, 95% CI 1.19-3.05, P < 0.008 for placebo, respectively). The most frequent adverse events leading to study discontinuation in tegaserod-treated patients were diarrhea (1.5%) and abdominal pain (0.9%). Overall 7% of IBS-C patients reported diarrhea compared to 12% of IBS-Mixed (placebo 2.4%, 1.8%, respectively). CONCLUSIONS: Tegaserod is effective in treating overall IBS symptoms in patients with IBS-Mixed and IBS-C.
Updates on treatment of irritable bowel syndrome.
World J Gastroenterol. 2008 May 7; 14(17): 2639-49
Hammerle CW, Surawicz CM
Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder characterized by abdominal pain and discomfort in association with altered bowel habits. It is estimated to affect 10%-15% of the Western population, and has a large impact on quality of life and (in)direct healthcare costs. IBS is a multifactorial disorder involving dysregulation within the brain-gut axis, and it is frequently associated with gastrointestinal motor and sensory dysfunction, enteric and central nervous system irregularities, neuroimmune dysregulation, and post-infectious inflammation. As with other functional medical disorders, the treatment for IBS can be challenging. Conventional therapy for those with moderate to severe symptoms is largely unsatisfactory, and the development of new and effective drugs is made difficult by the complex pathogenesis, variety of symptoms, and lack of objective clinical findings that are the hallmark of this disorder. Fortunately, research advances over the past several decades have provided insight into potential mechanisms responsible for the pathogenesis of IBS, and have led to the development of several promising pharmaceutical agents. In recent years there has been much publicity over several of these new IBS medications (alosetron and tegaserod) because of their reported association with ischemic colitis and cardiovascular disease. While these agents remain available for use under restricted prescribing programs, this highlights the need for continued development of safe and effective medication for IBS. This article provides a physiologically-based overview of recently developed and frequently employed pharmaceutical agents used to treat IBS, and discusses some non-pharmaceutical options that may be beneficial in this disorder.
Clinical practice. Irritable bowel syndrome.
N Engl J Med. 2008 Apr 17; 358(16): 1692-9
Mayer EA
Naunyn Schmiedebergs Arch Pharmacol. 2008 Jul; 378(1): 125-37
Smith JA, Beattie DT, Marquess D, Shaw JP, Vickery RG, Humphrey PP
The in vitro pharmacological profile of TD-5108, a novel, selective 5-HT(4) receptor agonist, was compared to that of clinically efficacious gastroprokinetic 5-HT(4) receptor agonists. TD-5108 produced an elevation of cyclic adenosine monophosphate in human embryonic kidney 293 cells expressing the human recombinant 5-HT(4(c)) (h5-HT(4(c))) receptor (pEC(50) = 8.3) and 5-HT(4) receptor-mediated relaxation of the rat esophagus (pEC(50) = 7.9) and contraction of the guinea pig colon (pEC(50) = 7.9). In all in vitro assays, TD-5108 was a high intrinsic activity agonist, unlike tegaserod, mosapride, and cisapride which, in the majority of test systems, had lower intrinsic activity. TD-5108 had high affinity (pK (i) = 7.7) and selectivity (>/=25-fold) for h5-HT(4(c)) receptors over other biogenic amine receptors. TD-5108 was >500-fold selective over other 5-HT receptors (including h5-HT(2B) and h5-HT(3A)) and, at 3 muM, had no effect on human ether-à-go-go-related gene K(+) channels. In conclusion, TD-5108 is a selective 5-HT(4) receptor agonist in vitro. The high intrinsic activity and preferential binding of TD-5108 to 5-HT(4) over other 5-HT receptors may result in an improved clinical profile for the treatment of gastrointestinal disorders of reduced motility.
Naunyn Schmiedebergs Arch Pharmacol. 2008 Jul; 378(1): 139-47
Beattie DT, Armstrong SR, Shaw JP, Marquess D, Sandlund C, Smith JA, Taylor JA, Humphrey PP
The in vivo preclinical pharmacodynamic profile of TD-5108, a selective 5-HT(4) receptor agonist with high intrinsic activity, was compared to that of the clinically studied gastrointestinal pro-kinetic agents, tegaserod, cisapride and mosapride. The activity of TD-5108 was evaluated in guinea pig colonic transit, rat oesophageal relaxation and dog gastrointestinal smooth muscle contractility models. Subcutaneous administration of TD-5108, tegaserod, cisapride and mosapride increased guinea pig colonic transit (rank order of potencies: TD-5108 > tegaserod > cisapride > mosapride). Following intravenous and intraduodenal dosing, TD-5108, tegaserod, cisapride and mosapride produced dose-dependent relaxation of the rat oesophagus. On a molar basis, TD-5108 was approximately twofold less potent than tegaserod following intravenous dosing but 6- or 86-fold more potent than cisapride or mosapride, respectively, and 9- or 18-fold more potent than tegaserod or cisapride, respectively, after intraduodenal administration. Orally dosed TD-5108 increased the contractility of the canine antrum, duodenum and jejunum with higher potency than tegaserod. The selective 5-HT(4) receptor agonist, TD-5108, demonstrates robust in vivo activity in the guinea pig, rat and dog gastrointestinal tracts.
Am J Gastroenterol. 2008 Apr; 103(4): 815-9
Schiller LR, Johnson DA
Several high-profile drug withdrawals for safety issues have brought into focus the FDA's process for approving drugs and monitoring adverse experiences with those agents after marketing has begun. Gastroenterologists and their patients have been affected adversely by removal from the marketplace of two licensed agents for irritable bowel syndrome (IBS): alosetron and tegaserod. The criteria used by the FDA for assessment of the risks and benefits of drugs used for functional bowel problems seem to be different than those used for the treatment of other conditions and have resulted in drastic limitation of access to these drugs rather than just warnings about risks as they are discovered. Decisions that affect the availability of drugs for patients with functional bowel disease should be discussed with clinicians who take care of those patients before going into effect. The absence of this sort of consultation leaves physicians with serious limitations on their abilities to take care of patients.