Psychological processes underlying the association between childhood trauma and psychosis in daily life: an experience sampling study.

BACKGROUND: Evidence has accumulated that implicates childhood trauma in the aetiology of psychosis, but our understanding of the putative psychological processes and mechanisms through which childhood trauma impacts on individuals and contributes to the development of psychosis remains limited. We aimed to investigate whether stress sensitivity and threat anticipation underlie the association between childhood abuse and psychosis. METHOD: We used the Experience Sampling Method to measure stress, threat anticipation, negative affect, and psychotic experiences in 50 first-episode psychosis (FEP) patients, 44 At-Risk Mental State (ARMS) participants, and 52 controls. Childhood abuse was assessed using the Childhood Trauma Questionnaire. RESULTS: Associations of minor socio-environmental stress in daily life with negative affect and psychotic experiences were modified by sexual abuse and group (all p FWE < 0.05). While there was strong evidence that these associations were greater in FEP exposed to high levels of sexual abuse, and some evidence of greater associations in ARMS exposed to high levels of sexual abuse, controls exposed to high levels of sexual abuse were more resilient and reported less intense negative emotional reactions to socio-environmental stress. A similar pattern was evident for threat anticipation. CONCLUSIONS: Elevated sensitivity and lack of resilience to socio-environmental stress and enhanced threat anticipation in daily life may be important psychological processes underlying the association between childhood sexual abuse and psychosis.

Randomized, double-blind, placebo-controlled, proof-of-concept study of the cortical spreading depression inhibiting agent tonabersat in migraine prophylaxis.

Tonabersat is a novel putative migraine prophylactic agent with an unique stereospecific binding site in the brain. Tonabersat has been shown, in animal models, to inhibit experimentally induced cortical spreading depression, the likely underlying mechanism for migraine aura, and cerebrovascular responses to trigeminal nerve stimulation. The aim was to study the potential for tonabersat as a migraine preventive. A randomized, double-blind, placebo-controlled, multicentre, parallel group study recruited patients with migraine with and without aura experiencing between two and six migraine attacks per month. After a 1-month baseline they received tonabersat 20 mg daily for 2 weeks and 40 mg daily for a further 10 weeks. The primary end-point was the change in mean number of migraine headache days between the third month and the baseline period in the intention-to-treat population comparing the placebo (n = 65) and tonabersat (n = 58) groups. At the primary end-point there was a 1.0-day (95% confidence interval -0.33, 2.39; P = 0.14) difference in reduction in migraine days between tonabersat and placebo. There were 10 secondary efficacy end-points, of which two were statistically significant. In month 3 of treatment, the responder rate, defined as a 50% reduction in migraine attacks, was 62% for tonabersat and 45% for placebo (P < 0.05), and the rescue medication use was reduced in the tonabersat group compared with placebo by 1.8 days (P = 0.02). Placebo responses were particularly high for all end-points. At least one treatment-emergent adverse event was reported in the tonabersat group in 61% of patients compared with 51% in the placebo group; none was worrisome. Placebo responses were unexpectedly high in this trial, complicating straightforward interpretation of the study results. The good tolerability and promising efficacy results support further exploration of higher doses of tonabersat in larger controlled trials.

Acute treatment of reflux oesophagitis: a multicentre trial to compare 150 mg ranitidine b.d. with 300 mg ranitidine q.d.s.

H2-receptor antagonists administered in conventional dosage regimens fail to heal a significant proportion of patients with moderate or severe reflux oesophagitis. We have compared the effects of a higher dose of ranitidine (300 mg q.d.s.) with the currently recommended dosage regimen (150 mg b.d.) in 138 patients suffering from reflux oesophagitis. After 4 weeks of treatment 29% of patients who received 150 mg ranitidine b.d., and 63% of patients who received 300 mg ranitidine q.d.s. had complete endoscopic healing of their lesions (P less than 0.0001). After 8 weeks these proportions had increased to 54% and 75%, respectively (P less than 0.01). After 4 weeks of treatment, compete symptomatic relief had been achieved in 46% of patients who received 150 mg ranitidine b.d. and in 67% of patients who received 300 mg ranitidine q.d.s. (P less than 0.05). After 8 weeks these proportions were 64% and 84%, respectively (P less than 0.05). Both dosage schedules were well-tolerated. We conclude that more rapid symptom relief and healing in reflux oesophagitis can be achieved with 300 mg ranitidine q.d.s. than with 150 mg ranitidine b.d.

Geographical differences of gastric ulcer healing rate in patients treated with ranitidine or placebo.

The literature was searched for clinical trials evaluating the use of 300 mg ranitidine daily in the acute treatment of gastric ulcer. All available trials were examined, and the results compared between countries to determine the extent of any geographical variation in ulcer healing rates. Published placebo studies in gastric ulcer were also reviewed for comparison. Sixty-six publications were inspected to determine the trial design, country of origin, gastric ulcer healing rates, determined endoscopically, and details of patient demography. Overall worldwide healing rates for ranitidine treatment were 63% at week 4 and 86% at week 8 (n = 2349 and 2256 respectively), compared with 34% at week 4 and 52% at week 8 for placebo (n = 790 and 231 respectively). Statistically significant differences were found between the healing rates for individual countries at week 4 (P less than 0.001) and week 8 (P less than 0.001). However, after exclusion of the results from Japan (35%, n = 278) and Yugoslavia (97%, n = 32) at week 4, and from Japan (80%, n = 467) and France (65%, n = 52) at week 8, the healing rates from the remaining countries were not statistically different from one another. The limited data available in relation to age, sex and smoking habits, or placebo healing rates contributed little to explaining these aberrant results. It is concluded that there is variation in gastric ulcer healing rates between countries, but only results from Japan seem to be out of line with the rest of the world.

Can higher doses of an H2-receptor antagonist accelerate duodenal ulcer healing?

Drugs that inhibit gastric acid secretion heal duodenal ulcers at a rate that correlates with the ability of individual treatment regimens to decrease 24-h intragastric acidity. As current therapeutic regimens of ranitidine decrease 24-h intragastric acidity submaximally, higher dosages may expedite duodenal ulcer healing. To test this hypothesis a randomized, double-blind clinical trial was conducted in 245 patients with duodenal ulcer to compare the effects of standard dose (300 mg nocte) and high-dose (300 mg q.d.s.) ranitidine. Patients were assessed after 2 weeks of treatment and, if unhealed, after a further 2 weeks of therapy. The therapeutic gain in ulcer healing at the 2-week endoscopy of the higher dose over the lower dose of ranitidine was 22% (68% vs 46%, P less than 0.001). The cumulative ulcer healing rates at the 4-week endoscopy were 88% and 92% for the standard and high-dose ranitidine groups, respectively (N.S.). By 2 weeks, 61% of patients treated with standard ranitidine therapy and 79% of those receiving 300 mg ranitidine q.d.s. were pain-free (P less than 0.01). A further 2 weeks of therapy enabled 88% and 97% of patients (N.S.) to become pain-free on these two regimens, respectively. The drug regimens were equally well tolerated. Thus higher-dose ranitidine can significantly accelerate the healing of duodenal ulcer with improvement in pain relief.

Ranitidine in the treatment of duodenal ulcer disease: relationship between antisecretory effect and ulcer healing rate.

The relationship between drug-induced suppression of intragastric acidity and the rate of duodenal ulcer healing was examined using data for a single drug, ranitidine, from 156 clinical trials involving 16,362 patients together with data on acid suppression from 37 studies of intragastric acidity in 630 subjects. In these studies ranitidine was given in doses ranging from 150 mg to 1200 mg per day administered in 9 different dosage regimens. The overall percentage of patients whose duodenal ulcers healed at 2 and 4 weeks on the different regimens was highly correlated with the percentage suppression of 24-hour intragastric acidity induced by different regimens. Thus the therapeutic benefit of a given ranitidine dosage regimen in healing duodenal ulcers relates directly to its antisecretory effect.

The safety of ranitidine in over a decade of use.

BACKGROUND: Ranitidine hydrochloride (Zantac) is one of the most extensively studied and widely used drugs of all time. This has provided an excellent opportunity to define its safety profile. METHODS: Data from 189 controlled clinical trials in which more than 26,000 patients received daily doses of ranitidine for 4 weeks or more were reviewed. More than 80% of patients were treated with up to 300 mg ranitidine daily; the remaining patients received doses of up to 1200 mg daily. Eighty-seven trials were placebo controlled. Analyses of post-marketing surveillance and a database of all spontaneously reported adverse events were also evaluated. RESULTS: Overall in the clinical trial programme adverse events were reported by 20% of those receiving ranitidine compared with 27% of those receiving placebo. The pattern of events was similar in all treatment groups with no evidence of dose-related toxicity in regimens encompassing an eightfold range of therapeutic doses. Similarly in a programme of studies designed to evaluate a dose of ranitidine of 75 mg for non-prescription (over-the-counter) use in the treatment of heartburn, ranitidine was not associated with an adverse event profile distinct from that of placebo. Analysis of spontaneously reported adverse event data allowed identification of rare idiosyncratic events. CONCLUSIONS: Review of data from a large population of controlled clinical trials with analyses of postmarketing surveillance studies and spontaneously reported adverse events confirmed the excellent safety profile of ranitidine.

Inhibition of intragastric acidity in healthy subjects dosed with ranitidine 75 mg: a comparative study with cimetidine and placebo.

BACKGROUND: Despite the widespread use of over-the-counter H2-receptor antagonists little is known about their duration of action on human gastric acid secretion. There are studies reporting inhibitory effects for up to 9 h post-dose but few data beyond this period. METHODS: Profiles of 20-h intragastric acidity were measured simultaneously in 24 healthy subjects who were dosed (at 12.30 h) with either ranitidine 75 mg, cimetidine 200 mg or placebo in a three-way crossover study, according to a standard protocol. Five-millilitre aliquots of gastric juice were aspirated half-hourly during the day (0-10 h post-dose) and hourly overnight (10-20 h post-dose). pH was measured to three decimal places with a glass electrode. Weighted intragastric acidity (AUC/time) was calculated for both day- and night-times using 2.5-h intervals during the day and 5-h intervals at night. Statistical analysis was by ANOVA. RESULTS: The results are expressed as mean weighted intragastric acidity (mmol/L). (i) Daytime (0-10 h post-dose): when dosed with placebo the weighted intragastric acidity was 31.03, decreasing to 10.37 (P < 0.001 vs. placebo) and 16.23 (P < 0.001 vs. placebo) when treated with ranitidine and cimetidine, respectively. Ranitidine inhibited weighted intragastric acidity to a greater degree than cimetidine (P < 0.001) during this period. (ii) Night-time (10-20 h post-dose): when dosed with placebo the weighted intragastric acidity was 21.36 decreasing to 16.65 (P < 0.001 vs. placebo) when dosed with ranitidine and remaining unchanged at 20.03 (P = 0.886 vs. placebo) when dosed with cimetidine. Ranitidine inhibited weighted intragastric acidity to a greater degree than cimetidine (P = 0.010) during this period. A sub-analysis of the two 5-h intervals showed that compared to placebo, ranitidine inhibited weighted intragastric acidity significantly in the 10-15 h period. However, its effect in the 15-20 h period did not differ from placebo. CONCLUSIONS: In healthy subjects, the inhibitory effect of ranitidine 75 mg on intragastric acidity can be detected 10-15 h after an oral dose. By contrast, the inhibitory effect of cimetidine 200 mg seems to be restricted to the first 10 h.

Acute treatment of reflux oesophagitis: a multicentre study to compare 150 mg ranitidine twice daily with 300 mg ranitidine at bedtime.

A randomized, double-blind, clinical trial was undertaken to compare 150 mg ranitidine b.d. with 300 mg ranitidine nocte in the treatment of reflux oesophagitis. Endoscopy data were evaluable for 336 patients after 8 weeks of treatment. At this time 75% of patients who received 150 mg ranitidine b.d., and 73% of those who received 300 mg nocte, had healed or showed endoscopic improvement to grade I oesophagitis. At 12 weeks these rates had increased to 89 and 88%, respectively. Oesophageal biopsies from 258 patients at 8 weeks showed histological improvement in 44 and 47% of those treated with 150 mg ranitidine b.d. and 300 mg ranitidine nocte, respectively. After 12 weeks histological improvement was apparent in 57 and 54% of biopsies from each group, respectively. Symptom severity and frequency was reduced to a similar extent by both treatments. Adverse events were reported by 15 patients. A 300-mg bedtime dose of ranitidine was found to be a well-tolerated, effective alternative to twice daily treatment in reflux oesophagitis.

A double-blind, randomized, placebo-controlled dose-ranging study to evaluate the efficacy of alosetron in the treatment of irritable bowel syndrome.

BACKGROUND: Irritable bowel syndrome is a common gastrointestinal disorder characterized by abdominal pain and discomfort and altered bowel habit. Antagonism at the 5-HT3 receptor may be of benefit in the treatment of irritable bowel syndrome. AIMS: To evaluate the effect of 12 weeks of treatment with alosetron, a 5-HT3 receptor antagonist at doses of 0.1 mg b.d., 0.5 mg b.d. and 2 mg b.d. in irritable bowel syndrome patients. METHODS: A double-blind, placebo-controlled, parallel-group study with a 2-week screening and a 12-week treatment period was conducted. A total of 462 patients (335 female) recorded details of the severity of their abdominal pain, and bowel function daily on a diary card throughout the study. At monthly clinic visits patients recorded the severity of their abdominal pain/discomfort and diarrhoea on a visual analogue scale. RESULTS: In the total population and in the female subpopulation (but not in males) alosetron 2 mg b.d. significantly increased the proportion of pain-free days and decreased the visual analogue scale score for diarrhoea compared with placebo. Alosetron at doses of 0.5 mg b.d. and 2 mg b.d. led to a significant hardening of stool, and a reduction in stool frequency in the total population. CONCLUSION: Alosetron at a dose of 2 mg b.d. is an effective treatment for female patients with irritable bowel syndrome.

Alosetron relieves pain and improves bowel function compared with mebeverine in female nonconstipated irritable bowel syndrome patients.

BACKGROUND: Irritable bowel syndrome is one of the most common gastrointestinal disorders, yet no therapy convincingly controls the multiple symptoms of this syndrome. AIM: To compare the efficacy and tolerability of the new 5-HT3-receptor antagonist alosetron and the smooth muscle relaxant mebeverine in a double-blind, multicentre, randomized trial. METHODS: Six hundred and twenty-three nonconstipated females with irritable bowel syndrome were randomized to receive alosetron 1 mg twice daily (n=319) or mebeverine 135 mg three times daily (n=304) for 12 weeks, followed by a 4-week post-treatment period. The primary efficacy end-point was monthly responders for adequate relief of irritable bowel syndrome related abdominal pain and discomfort (defined as patients reporting adequate relief on at least 2 out of 4 weeks). Secondary end-points included assessments of bowel function, including urgency, stool frequency and stool consistency. RESULTS: There were significantly more responders in the alosetron group compared with mebeverine at months 2 and 3 (P < 0.01). Compared with mebeverine, the alosetron group experienced significant decreases in proportion of days with urgency and mean stool frequency, and had firmer stools within 1 week of starting treatment. A similar proportion of patients reported adverse events in the two treatment groups. CONCLUSIONS: In nonconstipated female irritable bowel syndrome patients, alosetron is significantly more effective than mebeverine in improving symptoms.

Does ranitidine affect blood alcohol concentrations?

No interaction occurs between ranitidine and alcohol when alcohol 0.3 g/kg or more is taken by either fed or fasted subjects. Ranitidine is associated with small increases (2-4 mg/dl) in blood alcohol concentrations in subjects given alcohol 0.15 g/kg under specific experimental conditions. Mean peak blood alcohol concentrations nevertheless remain low (< 20 mg/dl) after the amount, which is equivalent to about 3 oz of wine or 1 oz of 80-proof liquor. Such changes also occur when alcohol is ingested after different types of foods, and are smaller than the increases when it is drunk on an empty compared with a full stomach. The pharmacokinetic effect seen with ranitidine is without apparent clinical or social significance.

Combination of ranitidine and cisapride in the treatment of reflux oesophagitis.

OBJECTIVE: To compare the efficacy of treatment for 8 or 12 weeks with a combination of 150 mg ranitidine twice daily plus 20 mg cisapride twice daily with ranitidine 150 mg twice daily alone in patients with moderate-to-severe reflux oesophagitis. DESIGN: A double-blind, randomized, parallel-group clinical trial. SETTING: Forty-two out-patient centres in the UK, Germany, Ireland, Denmark and South Africa. PATIENTS: A total of 344 symptomatic patients with endoscopically confirmed reflux oesophagitis (Hetzel grade 3 or 4) were randomly assigned to receive the study medication. INTERVENTIONS: Patients underwent a follow-up endoscopy after 8 weeks' treatment. Healing was defined as Hetzel grade 0 or 1 upon endoscopy. Patients with unhealed oesophagitis continued their allocated treatment regimen for a further 4 weeks before undergoing a repeat endoscopy. MAIN OUTCOME MEASURES: The primary efficacy analysis was based on a comparison of 12-week cumulative healing rates between the two groups. RESULTS: A statistically significant difference (P = 0.015) in the cumulative healing rate was observed between patients given ranitidine plus cisapride (82%) and those given ranitidine alone (71%). Oesophagitis in patients who received the combination was twice as likely to heal as that in patients who received ranitidine alone. CONCLUSION: A combination of 150 mg ranitidine twice daily and 20 mg cisapride twice daily is a safe and effective treatment for moderate-to-severe reflux oesophagitis and offers increased efficacy over ranitidine alone.

Ranitidine bismuth citrate plus clarithromycin for the eradication of H. pylori.

Reported observed intention-to-treat eradication rates for ranitidine bismuth citrate plus clarithromycin for 14 days range from 70-86% in studies from the USA and 82-96% in multinational studies carried out primarily in Europe. Two double-blind head-to-head comparisons with omeprazole plus clarithromycin or amoxycillin have shown that ranitidine bismuth citrate plus clarithromycin gives considerably higher eradication rates than the omeprazole based regimens. Ongoing studies will define the efficacy of shorter duration dual therapies and provide further data on two antibiotics with ranitidine bismuth citrate. The possibility that ranitidine bismuth citrate may help in the eradication of resistant organisms and even in the prevention of primary resistance requires further work to expand the preliminary in vitro observations. In the meantime, it can be concluded that ranitidine bismuth citrate, when used in conjunction with clarithromycin for 14 days, is an effective therapy for the eradication of H. pylori.

Prevention of relapse in reflux esophagitis: a placebo controlled study of ranitidine 150 mg bid and 300 mg bid.

OBJECTIVE: To compare the efficacy and safety of long term use of ranitidine 150 mg bid, 300 mg bid and placebo in prevention of endoscopic and symptomatic relapse of reflux esophagitis in an international, double-blind, placebo controlled, parallel group study. PATIENTS AND METHODS: A total of 279 patients at least 18 years old from hospital out-patient departments with healed esophagitis (grade 0) with no or mild symptoms entered the study. Patients were randomly allocated to receive ranitidine 150 mg, 300 mg placebo twice daily for 48 weeks. Patients returned for symptom assessments at eight-week intervals and for re-endoscopy every 16 weeks. RESULTS: Both ranitidine regimens were significantly more effective than placebo in preventing endoscopic and symptomatic relapse of reflux esphagitis (p = 0.003 for ranitidine 150 mg bid; P < 0.001 for ranitidine 300 mg bid). No statistically significant differences were observed in relapse rates between the two ranitidine regiments. The percentage of patients with endoscopic relapse (grade 2) after 48 weeks were 60%, 37% and 27% for placebo, ranitidine 150 mg bid and ranitidine 300 mg bid, respectively (P = 0.002 for ranitidine 150 mg bid versus placebo; P < 0.001 for ranitidine 300 mg bid versus placebo). Ranitidine was well tolerated. CONCLUSIONS: Ranitidine 150 mg bid and 300 mg bid are safe and effective treatments in the prevention of reflux esophagitis relapse.

The pharmacology of histamine H2-receptor antagonists.

The structure of the first histamine H2-receptor antagonist, burimamide was described in 1972. Since then, numerous compounds with diverse chemical structures have been shown to possess H2-receptor antagonist activity. Most of these compounds comprise an aromatic ring and polar group linked by a flexible chemical chain. Currently five H2-receptor antagonists are available for therapeutic use. In vitro studies have confirmed the competitive nature of the interaction between agonist and antagonist for these compounds and a comparison of the pA2 values generated shows a rank order of potency cimetidine less than nizatidine = ranitidine less than or equal to roxatidine less than famotidine. The duration of action of these agents is largely dependent upon their pharmacokinetic properties; with the possible exception of roxatidine, all have plasma elimination half-lives in the range 2-4 hours. Competitive antagonists with a high degree of selectivity for the H2-receptor and with a longer duration of action are currently being investigated, e.g., sufotidine. In addition to competitive agents, several non-competitive H2-antagonists, e.g., loxtidine, have been described. These have a prolonged duration of action. Relative potency varies between animal species and pharmacological models studied but the results of animal pharmacological studies have generally provided a good indication of the likely effects in man. Studies of 24-hour intragastric acidity represent the most physiological model available in man for evaluating the effects of different antisecretory drug regimens. Comparative studies with ranitidine 150 mg b.i.d. and cimetidine 400 mg b.i.d. have shown a reduction in 24-hour acidity of 65% and 30%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The adaptability rating for military aeronautics: an historical perspective of a continuing problem.

Healthy candidates for military flying training may vary considerably in their ability and in their motivation to fly. A variety of tests are used to predict flying ability, but motivation may be assessed only through such subjective measures as a semi-structured interview. This paper reviews the historical background of such interviews in the U.S. Army and the U.S. Air Force, and suggests some possible improvements.

Onset of action of antisecretory drugs: beneficial effects of a rapid increase in intragastric pH in acid reflux disease.

BACKGROUND: The majority of patients who have symptomatic acid reflux disease will have a normal oesophageal mucosa or will have only a mild degree of oesophagitis. Treatment to relieve symptoms as they occur may be the best way to manage these patients, to whom the speed of symptom relief is of primary importance. The effervescent complex used to formulate effervescent ranitidine contains sodium bicarbonate and monosodium citrate, and has, therefore, an intrinsic acid-neutralizing capacity in addition to the well-documented antisecretory activity. METHODS: The results of studies of the effects of effervescent ranitidine tablets on intragastric pH and on the relief of heartburn are reviewed. RESULTS AND CONCLUSIONS: When compared with the standard ranitidine tablet, the effervescent formulation results in a significantly greater and more rapid rise in intragastric pH in the hour immediately after dosing. Comparative studies show that intragastric pH is raised significantly faster after a single dose of effervescent ranitidine than after a famotidine rapid release tablet and after either an omeprazole or a lansoprazole capsule. In patients with acid reflux disease, effervescent ranitidine provides quicker relief of symptoms than a standard tablet and is preferred by most patients for this reason. The majority of patients (more than 80%) report symptom relief within 60 min of taking effervescent ranitidine.

Cardiovascular responses in healthy subjects to a novel oral dopamine agonist, fenoldopam.

Two double-blind randomized crossover studies were carried out in healthy male subjects to determine the cardiovascular effects of fenoldopam and to assess whether they could be modified by metoclopramide. Blood pressure (BP) and heart rate (HR) were measured supine and upright, before and for up to 4 h after dosing. Single oral doses of fenoldopam 50, 100 or 150 mg or placebo were administered in one study. In the other study, subjects received 20 mg metoclopramide or placebo intravenously, 20 min before an oral dose of 100 mg fenoldopam or placebo. Fenoldopam produced decreases in diastolic BP and increases in HR indicative of an orally active systemic arteriolar vasodilator. Mean peak responses occurred 30-60 min after dosing and values had returned to pretreatment levels within 3-4 h. The decrease in diastolic BP was partially attenuated by pretreatment with metoclopramide. Thus, at least in part, the fall in BP following fenoldopam could be due to an interaction with dopamine receptors.