The problems of anticholinergic adverse effects in older patients

The old saying 'red as a beet, dry as a bone, blind as a bat, hot as a hare, mad as a hatter' is often quoted when describing the autonomic effects of drugs that block the muscarinic cholinergic system. These effects may be subtle or dramatic, yet can be overlooked or discounted as a natural consequence of old age. Elderly patients can be particularly sensitive to the anticholinergic action of drugs because of physiological and pathophysiological changes that often accompany the aging process. The use of multiple drugs, a common finding in older patients, may result in pharmacodynamic and pharmacokinetic drug interactions that heighten anticholinergic effects. While the classic anticholinergic problems of decreased secretions, slowed gastrointestinal motility, blurred vision, increased heart rate, heat intolerance, sedation and possibly mild confusion, may be uncomfortable for a younger patient in relatively good health, these effects can be disastrous for older patients. Even the most common peripheral anticholinergic complaint of dry mouth can reduce the ability to communicate, predispose to malnutrition, promote mucosal damage, denture misfit or dental caries, and increase the risk of serious respiratory infection secondary to loss of antimicrobial activity of saliva. Mydriasis and the inability to accommodate will impair near vision and may precipitate narrow angle glaucoma in predisposed patients, but less obviously could lead to an increased risk of accidents, including falls. Somatic complaints of constipation and urinary hesitancy, could, in the presence of anticholinergic challenge, result in faecal impaction or urinary retention. Cardiac effects may be poorly tolerated. Increases in heart rate may precipitate or worsen angina. Finally, thermoregulatory impairment induced by anticholinergics, which block the ability to sweat, may lead to life threatening hyperthermia. Central anticholinergic effects range from sedation, mild confusion and inability to concentration to frank delirium. Even mild effects can reduce function and increase dependency. At any level of care, the loss of independence increases the caregiver burden, costs, and most importantly, can negatively affect quality of life. Many age-related and disease-related conditions may predispose elderly patients to anticholinergic drug toxicity. Careful attention to anticholinergic effects when prescribing drugs, patient education, regular review of the entire drug regimen, and familiarity with the signs and symptoms of anticholinergic toxicity will help to reduce the risk of drug-induced problems.

Effects of tolterodine, trospium chloride, and oxybutynin on the central nervous system

Antimuscarinic compounds are increasingly used to treat the symptoms of overactive bladder; however, their use is often restricted by peripheral adverse effects (AEs). On the other hand, data regarding their influence on the central nervous system (CNS) are limited. This randomized, single-blind, parallel-group quantitative-topographical EEG (qEEG) study of clinical phase I investigates the potential CNS adverse effects of the three antimuscarinic drugs--tolterodine, oxybutynin, and trospium chloride--in comparison to placebo. Overall, 4 x 16 (total 64) young, healthy male volunteers were included in the study. The subjects were given either placebo or the clinically recommended daily doses of the drugs dispensed in three doses on a single day (tolterodine 2 mg bid and once placebo, total 4 mg/d; oxybutynin 5 mg tid, total 15 mg/d; and trospium chloride 15 mg tid, total 45 mg/d). The qEEG was recorded prior to and up to 4 hours after each intake of the trial medication (a total of 10 qEEG sessions) under three different conditions: at rest with eyes open, eyes closed, and under mental demand. The drug tolerability was subjectively evaluated by the volunteer and the investigator. In comparison to placebo (10% confidence interval), tolterodine and trospium chloride did not induce changes of the qEEG power in five of the six frequency bands (i.e., delta, alpha 1, alpha 2, beta 1, and beta 2). Isolated power decreases were only observed in the theta frequency band. In contrast, oxybutynin caused significant power reductions in four frequency bands (theta, alpha 1, alpha 2, and beta 1; p < 0.01). The subjectively evaluated drug tolerability was comparable between all treatment groups, although differences in the AE occurrence existed, with the AE frequency being higher in the oxybutynin group. The results of this study support the findings that oxybutynin as a tertiary amine crosses the blood-brain barrier, causing significant qEEG activity changes and more pronounced central adverse effects. Although tolterodine is also a tertiary amine, it shows limited effects on qEEG activity (i.e., slight theta power reductions), comparable to the effects of trospium chloride, a quarternary amine, which barely crosses the blood-brain barrier. The minimal qEEG changes observed with tolterodine and trospium chloride reflect most probably a rebound message from the peripheral target organs. Prescription of oxybutynin thus implicates a higher risk of CNS side effects.

Randomized, double-blind, multicenter trial on treatment of frequency, urgency and incontinence related to detrusor hyperactivity: oxybutynin versus propantheline versus placebo

Clinical efficacy and adverse effects of oxybutynin and propantheline in the treatment of symptoms related to detrusor hyperactivity were studied in a randomized, controlled, double-blind multicenter trial. Of 169 patients entered into the study 154 were evaluable for statistical analysis. Mean grade of improvement (visual analogue scale) was significantly higher with oxybutynin (58.2%) versus propantheline (44.7%) and placebo (43.4%). Mean bladder volume at first involuntary cystometric contraction was significantly increased with oxybutynin (+57.0 ml.) versus placebo (-9.7 ml.). Mean maximum cystometric bladder capacity was also significantly increased with oxybutynin (+80.1 ml.) versus placebo (+22.5 ml.). Rate of inquired possible adverse effects was significantly higher for oxybutynin (63%) versus propantheline (44%) and placebo (33%). However, only 5 patients dropped out of the study because of adverse effects (oxybutynin 2 and propantheline 3). No serious or lasting adverse effects were encountered with dryness of the mouth being the major complaint. Oxybutynin has statistically significant effects on subjective symptoms and objective urodynamic parameters in patients with detrusor hyperactivity compared to propantheline.

Association of postoperative delirium with raised serum levels of anticholinergic drugs

Drugs with anticholinegic effects are often used in surgical procedures and may impair higher cognitive functions and produce delirious states. This prospective study examined the relation between serum levels of anticholinergic drugs, measured by a radioreceptor assay, and the development of delirium in patients undergoing cardiac surgery. Most patients who had postoperative delirium had high serum levels of anticholinergic drugs, whereas those who remained cognitively intact had low levels; and impairment in cortical function correlated with serum levels of anticholinergic drugs (p less than 0.001). Raised serum levels of drugs with anticholinergic effects may contribute to the development of delirium, and to the increase in risk of morbidity following cardiac surgery.

Asystole complicating physostigmine treatment of tricyclic antidepressant overdose

Physostigmine is a commonly used therapy for the anticholinergic manifestations of tricyclic antidepressant (TCA) overdose. We describe two patients with TCA toxicity who developed asystole following the administration of physostigmine to treat seizures.

Physostigmine. Its use in acute anticholinergic syndrome with antidepressant and antiparkinson drugs

We reviewed the use of physostigmine in the diagnosis and management of acute toxic psychosis due to drugs with anticholinergic properties. The syndrome of agitation and toxic confusional psychosis associated with peripheral signs of cholinergic blockade is produced by several plant toxins, antispasmodics, ophthalmic preparations, and certain proprietary sedatives, as well as antiparkinson medications, antidepressants, and some antipsychotic drugs. Physostigmine, uniquely among the available reversible anticholinesterase agents, can pass the blood-brain barrier to exert central as well as peripheral cholinomimetic actions to reverse this syndrome. Psychiatrists should make more use of this safe, specific, rapid, and effective treatment for anticholinergic drug toxicity, and should particularly be alert to reversible anticholinergic brain syndromes associated with antidepressants and antiparkinson medications, and even with antipsychotic medications.

The effects of oxitropium bromide on exercise performance in patients with stable chronic obstructive pulmonary disease. A comparison of three different exercise tests

The purpose of the present study was to compare the characteristics of three different exercise tests in evaluating the effects of oxitropium bromide on exercise performance. Thirty-eight males with stable chronic obstructive pulmonary disease (COPD) (FEV(1) = 40.8 +/- 16.5% predicted; mean +/- SD) completed randomized, double-blind, placebo-controlled, crossover studies for each exercise test. The exercise tests were performed 60 min after the inhalation of either oxitropium bromide 400 microg or placebo. The patients performed 6-min walking tests (6MWT) on Days 1 and 2, progressive cycle ergometry (PCE) on Days 3 and 4, and cycle endurance tests at 80% of the maximal workload of PCE on Days 5 and 6. Spirometry was conducted before and at 45 and 90 min after the inhalation. Oxitropium bromide significantly increased FEV(1) as compared with placebo. Oxitropium bromide increased the endurance time significantly, by 19% (p < 0.001), and caused a small but significant increase in the 6-min walking distance by 1% (p < 0.05), but induced no significant increase in maximal oxygen consumption (V O(2)max) in PCE. The responses in these three exercise tests were different, and we conclude that the endurance test was the most sensitive in detecting the effects of inhaled anticholinergic agents on exercise performance in patients with stable COPD. An endurance procedure may be performed to detect clinical changes in evaluating the effects of oxitropium bromide on exercise performance.

Tizanidine. A review of its pharmacology, clinical efficacy and tolerability in the management of spasticity associated with cerebral and spinal disorders

The central alpha 2 adrenoceptor agonist tizanidine is a myotonolytic agent used in the treatment of spasticity in patients with cerebral or spinal injury. Wide interpatient variability in the effective plasma concentrations of tizanidine means that the optimal dosage must be titrated over 2 to 4 weeks for each patient (dosages of 2 to 36 mg/day have been used in clinical trials). Maximum effects occur within 2 hours of administration. Antispastic efficacy has been demonstrated for tizanidine in placebo-controlled trials, with reduction in mean muscle tone scores of 21 to 37% versus 4 to 9% for patients receiving placebo. Improvement in muscle tone occurred in 60 to 82% of tizanidine recipients, compared with 60 to 65% of baclofen and 60 to 83% of diazepam recipients. Spasm frequency and clonus are also reduced by tizanidine. The most common adverse effects associated with tizanidine are dry mouth and somnolence/drowsiness. Muscle strength, as assessed by objective means, appears not to be adversely affected by tizanidine and subjective muscle weakness is reported less often by tizanidine recipients than by those receiving baclofen or diazepam. Global tolerability was assessed as good to excellent in 44 to 100% of patients receiving tizanidine, compared with 38 to 90% of baclofen and 20 to 54% of diazepam recipients. In conclusion, tizanidine is an antispastic agent with similar efficacy to that of baclofen and a more favourable tolerability profile. While drowsiness is a frequently reported adverse effect with both agents, subjective muscle weakness appears to be less of a problem with tizanidine than with baclofen. Tizanidine, therefore, appears to be an attractive therapeutic alternative for patients with spasticity associated with cerebral or spinal damage.

Enteric-coated peppermint-oil capsules in the treatment of irritable bowel syndrome: a prospective, randomized trial

To determine the efficacy and tolerability of an enteric-coated peppermint-oil formulation (Colpermin), we conducted a prospective, randomized, double-blind, placebo-controlled clinical study in 110 outpatients (66 men/44 women; 18-70 years of age) with symptoms of irritable bowel syndrome. Patients took one capsule (Colpermin or placebo) three to four times daily, 15-30 min before meals, for 1 month. Fifty-two patients on Colpermin and 49 on placebo completed the study. Forty-one patients on Colpermin (79%) experienced an alleviation of the severity of abdominal pain (29 were pain-free); 43 (83%) had less abdominal distension, 43 (83%) had reduced stool frequency, 38 (73%) had fewer borborygmi, and 41 (79%) less flatulence. Corresponding figures for the placebo group were: 21 patients (43%) with reduced pain (4 were pain-free), 14 (29%) with reduced distension, 16 (32%) with reduced stool frequency, 15 (31%) with fewer borborygmi, and 11 (22%) with less flatulence. Symptom improvements after Colpermin were significantly better than after placebo (P < 0.05; Mann-Whitney U-test). One patient on Colpermin experienced heartburn (because of chewing the capsules) and one developed a mild transient skin rash. There were no significant changes in liver function test results. Thus, in this trial, Colpermin was effective and well tolerated.

Comparison of the anticholinergic bronchodilator ipratropium bromide with metaproterenol in chronic obstructive pulmonary disease. A 90-day multi-center study

The short- and long-term efficacy and safety of an inhaled quaternary ammonium anticholinergic agent, ipratropium bromide, and a beta agonist aerosol, metaproterenol, were compared in 261 nonatopic patients with chronic obstructive pulmonary disease (COPD). The study was a randomized, double-blind, 90-day, parallel-group trial. On three test days-one, 45, and 90-mean peak responses for forced expiratory volume in one second and forced vital capacity and mean area under the time-response curve were higher for ipratropium than for metaproterenol. Clinical improvement was noted in both treatment groups, especially during the first treatment month, with persistence of improvement throughout the remainder of the study. Side effects were relatively infrequent and generally mild; tremor, a complication of beta agonists, was not reported by any subject receiving ipratropium. These results support the effectiveness and safety of long-term treatment with inhaled ipratropium in COPD.

Causes of urinary incontinence after acute hemispheric stroke

BACKGROUND AND PURPOSE

We prospectively studied bladder function in stroke patients to determine the mechanisms responsible for poststroke urinary incontinence.

METHODS

Fifty-one patients with recent unilateral ischemic hemispheric stroke admitted to a neurorehabilitation unit were enrolled. The presence of urinary incontinence was correlated with infarct location, neurological deficits, and functional status. Urodynamic studies were performed on all incontinent patients.

RESULTS

Nineteen patients (37%) were incontinent. Incontinence was associated with large infarcts, aphasia, cognitive impairment, and functional disability (p < 0.05) but not with age, sex, side of stroke, or time from stroke to entry in the study. Urodynamic studies, performed on all 19 incontinent patients, revealed bladder hyperreflexia in 37%, normal studies in 37%, bladder hyporeflexia in 21%, and detrusor-sphincter dyssynergia in 5%. All of the patients with normal urodynamic studies were aphasic, demented, or severely functionally impaired. All of the patients with hyporeflexic bladders had underlying diabetes or were taking anticholinergic medications. Forty-six percent of incontinent patients treated with scheduled voiding alone were continent at discharge compared with 17% of patients treated pharmacologically.

CONCLUSIONS

There are three major mechanisms responsible for poststroke urinary incontinence: 1) disruption of the neuromicturition pathways, resulting in bladder hyperreflexia and urgency incontinence; 2) incontinence due to stroke-related cognitive and language deficits, with normal bladder function; and 3) concurrent neuropathy or medication use, resulting in bladder hyporeflexia and overflow incontinence. Urodynamic studies are of benefit in establishing the cause of incontinence. Scheduled voiding is a useful first-line treatment in many cases of incontinence.

The pharmacokinetics of intravesical and oral oxybutynin chloride

In 8 children with cystometric evidence of bladder instability and marked systemic side effects to oral oxybutynin we investigated the efficacy of intravesical instillation and compared the pharmacokinetics of both routes of delivery. In addition, 4 healthy dogs underwent intravesical instillation for pharmacokinetic studies. Intravesical oxybutynin was well tolerated, efficacious and rapidly absorbed, resulting in plasma concentrations markedly higher than after oral administration. In only 2 patients did this method of instillation result in side effects, and both had previously undergone bladder augmentation. This lack of significant systemic side effects despite high plasma concentrations suggests that a metabolite may be generated after oral administration that is responsible for the side effects. These studies demonstrate that the mode of administration affects the mechanism of action, side effects, pharmacokinetics and metabolism of oxybutynin, and that intravesical instillation is clinically effective and results in minimal side effects.

Salivary gland dysfunction: causes, symptoms, treatment

The three most common known causes of salivary gland dysfunction are medication usage, radiation therapy and Sjogren's syndrome. Current therapeutic options to treat salivary dysfunction are limited. Clinical considerations as well as the outlook for individuals experiencing salivary dysfunction are discussed.

Controlled, double-blind, multicentre clinical trial to investigate long-term tolerability and efficacy of trospium chloride in patients with detrusor instability

Our objectives were to ascertain the tolerability and efficacy of trospium chloride in doses of 20 mg twice daily for long-term therapy (52 weeks) in patients with urge syndrome. The trial comprised a total of 358 patients with urge syndrome or urge incontinence. After randomisation in the ratio of 3:1, participants were treated continuously for 52 weeks with either trospium chloride (20 mg twice daily) or oxybutynin (5 mg twice daily). At intervals of 4-8 weeks, patients were physically examined with measurements of blood pressure and pulse rate, were questioned about any adverse events, checked for compliance and underwent relevant laboratory tests. As an additional safety measure, an ECG was made at 26 and 52 weeks. Urodynamic measurements were performed at the beginning, and at 26 and 52 weeks to determine the maximal cystometric bladder capacity. Among others things, the frequencies of micturition, incontinence and number of urgency events were recorded in patient diary protocols in weeks 0, 2, 26 and 52. The evaluation of vital parameters, laboratory results and ECGs did not show any relevant changes attributable to the action of the anticholinergics. Analysis of the micturition diary clearly indicated a reduction of the micturition frequency, incontinence frequency, and a reduction of the number of urgencies in both treatment groups. Mean maximum cystometric bladder capacity increased during treatment with trospium chloride by 92 ml after 26 weeks and 115 ml after 52 weeks (P=0.001). Further comparison with oxybutynin did not reveal any statistically significant differences in urodynamic variables between the drugs. Adverse events occurred in 64.8% of the patients treated with trospium chloride and 76.7% of those treated with oxybutynin. The main symptom encountered in both treatment group was dryness of the mouth. For patients on trospium chloride, the estimated risk of an unexpected adverse event was 0.027 per patient per week for all adverse events and 0.009 for dryness of the mouth, resulting in a considerably lower risk during treatment given with trospium chloride than with oxybutynin (0.045 and 0.021, respectively). An overall assessment for each of the drugs reveals a comparable efficacy level and a better benefit-risk ratio for trospium chloride than for oxybutynin due to better tolerability.

Trospium chloride versus oxybutynin: a randomized, double-blind, multicentre trial in the treatment of detrusor hyper-reflexia

OBJECTIVE

To compare trospium chloride (TCl), a quaternary ammonium derivative with atropine-like effects and predominantly antispasmodic activity, with oxybutynin (Oxy) in terms of efficacy and adverse effects.

PATIENTS AND METHODS

In a randomized, double-blind, multicentre trial, 95 patients with spinal cord injuries and detrusor hyper-reflexia were studied. Treatment consisted of three doses per day over a 2 week period, with either Oxy (5 mg three times daily) or with TCl (20 mg twice daily) with an additional placebo at midday. The results were evaluated with regard to changes in objective (urodynamic) data and subjective symptoms as well as the incidence/severity of adverse effects.

RESULTS

With both drugs there was a significant increase in maximum bladder capacity, a significant decrease in maximum voiding detrusor pressure and a significant increase in compliance and residual urine; there were no statistically significant differences between the treatment groups. The percentage of patients who reported severe dryness of the mouth was considerably lower (4%) in those receiving TCl 2 x 20 mg/day than in those receiving Oxy (23%) 3 x 5 mg/day. Withdrawal from treatment was also less frequent in those receiving TCl (6%) than in those receiving Oxy (16%).

CONCLUSION

Trospium chloride and oxybutynin, judged in terms of objective urodynamic parameters, are of substantially equal value as parasympathetic antagonists. However, assessment of tolerance in terms of adverse drug effects showed that TCl had certain advantages.

Hyoscine butylbromide: a review of its use in the treatment of abdominal cramping and pain

Abdominal cramping and pain is a frequent problem in the adult population of Western countries, with an estimated prevalence of < or =30%. Hyoscine butylbromide (scopolamine butylbromide) [Buscopan/Buscapina] is an antispasmodic drug indicated for the treatment of abdominal pain associated with cramps induced by gastrointestinal (GI) spasms. It was first registered in Germany in 1951 and marketed in 1952, and has since become available worldwide both as a prescription drug and as an over-the-counter medicine in many countries. This article reviews the pharmacology and pharmacokinetic profile of hyoscine butylbromide, and summarises efficacy and safety data from clinical trials of this drug for abdominal cramping and pain. Pharmacological studies have revealed that hyoscine butylbromide is an anticholinergic drug with high affinity for muscarinic receptors located on the smooth-muscle cells of the GI tract. Its anticholinergic action exerts a smooth-muscle relaxing/spasmolytic effect. Blockade of the muscarinic receptors in the GI tract is the basis for its use in the treatment of abdominal pain secondary to cramping. Hyoscine butylbromide also binds to nicotinic receptors, which induces a ganglion-blocking effect. Several pharmacokinetic studies in humans have consistently demonstrated the low systemic availability of hyoscine butylbromide after oral administration, with plasma concentrations of the drug generally being below the limit of quantitation. The bioavailability of hyoscine butylbromide, estimated from renal excretion, was generally <1%. However, because of its high tissue affinity for muscarinic receptors, hyoscine butylbromide remains available at the site of action in the intestine and exerts a local spasmolytic effect.Ten placebo-controlled studies have evaluated the efficacy and safety of oral or rectal hyoscine butylbromide. Hyoscine butylbromide was considered beneficial in all of these trials, which supports its use in the treatment of abdominal pain caused by cramping. Hyoscine butylbromide is barely absorbed and detectable in the blood and does not penetrate the blood-brain barrier, and is, therefore, generally well tolerated. Few adverse events have been reported; in particular, no significant increases in the incidence of anticholinergic-related adverse effects have been observed. In summary, hyoscine butylbromide appears to be a valuable treatment option for patients with symptoms of abdominal pain or discomfort associated with cramping.

The risk of anticholinergic toxicity in the elderly: a study of prescribing practices in two populations

The potential for anticholinergic toxicity due to concurrent use of medications was assessed among 5,902 continuous nursing home residents and a comparable group of ambulatory patients. During the study year nearly 60% of the nursing home residents and 23% of the ambulatory patients received drugs with anticholinergic properties. Based on recommended doses of the drugs, 565 of the nursing home patients and 413 of the ambulatory patients could have received three or more anticholinergic medications concurrently. An examination of nursing home patients receiving the most frequently prescribed antipsychotic and tricyclic antidepressant drugs concurrently revealed that physicians did not choose drugs selectively within the two classes in order to minimize the potential for anticholinergic toxicity. The findings of this study suggest that the risk of anticholinergic toxicity may be underestimated by physicians.

Oxybutynin with bladder retraining for detrusor instability in elderly people: a randomized controlled trial

The aim of this study was to examine the efficacy of oxybutynin plus bladder training in the treatment of detrusor instability in frail elderly patients living independently in the community. It was a randomized, double-blind, placebo-controlled parallel-group trial of oxybutynin in 57 elderly patients (mean age 82.2, SD 6.06), with frequency and incontinence due to detrusor instability. After a 2-week run-in period patients received a bladder training and drug or placebo for the next 6 weeks. Outcome measures were changes in frequency and incontinence, recorded throughout on diary charts, and subjective evaluation of symptoms ('better'/'not better', and using a four-point scale 'cure' to 'no change'). Oxybutynin was superior to placebo in reducing daytime frequency [95% confidence interval (CI) of difference in change in frequencies totalled over 14 days was -27.0, -6.0; p = 0.003] and in producing subjective benefit (at day 29 only), when 24/28 (86%) patients on oxybutynin described benefit compared with 16/29 (55%) on placebo (p = 0.02). There was no difference between the groups in reduction of incontinent episodes. The median dose of oxybutynin titrated for therapeutic effect was 5 mg/day, and for placebo 10 mg/day (CI of difference 0.001, 5.001; p = 0.05). Side-effects reported were of similar frequency (50%) in the two groups. We conclude that oxybutynin with bladder training is superior to bladder training alone in reducing frequency due to detrusor instability in very elderly people living at home.

Depression, parkinsonian symptoms, and negative symptoms in schizophrenics treated with neuroleptics

To determine whether depression and neuroleptic-induced parkinsonism confound the clinical assessment of negative symptoms in schizophrenics, we evaluated 45 outpatient schizophrenics for depression, parkinsonian symptoms, and negative symptoms using standard clinical rating scales. Neuroleptic and anticholinergic dose and plasma activity were also determined. Associations between negative symptoms and these clinical and drug variables were examined using a multivariate statistical model. Negative symptoms were significantly correlated with several parkinsonian symptoms, some vegetative features of depression, and with anticholinergic dose. No significant correlations were found between negative symptoms and cognitive features of depression, or neuroleptic and anticholinergic plasma activity. These findings suggest that assessment criteria for negative symptoms, depression, and drug-induced parkinsonism overlap in treated schizophrenics. Strategies for differentiating these clinical syndromes are discussed.

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.

Meperidine-induced delirium

Despite the widespread use of meperidine as an analgesic, its potential for producing delirium has been overlooked. Six cases demonstrating meperidine-induced behavioral toxicity are reported. Toxicity was more likely when meperidine was combined with cimetidine or drugs having anticholinergic activity. Discontinuation of meperidine and substitution of morphine for analgesia were usually successful in treating the delirium. Physostigmine reversed the delirium in one patient. The authors suggest that the delirium results from the excessive anticholinergic activity of meperidine or its only active metabolite, normeperidine.

The lower esophageal sphincter. Physiologic and clinical aspects

Current concepts in physiology and pathophysiology of lower esophageal sphincteric mechanism are reviewed. With recent advances in manometric method for more accurate in-vivo human studies combined with in-vivo and in-vitro studies in animal models, there is much information regarding function of this sphincter. Three components of sphincter control have been identified: specialized circular smooth muscle at esophagogastric junction, autonomic nervous system, and probable physiology effects of gastrointestinal hormones, particularly gastrin. Clinical syndromes of sphincteric dysfunction have been identified relative to these three controlling elements. Foods and drugs that adversely effect sphincter pressure have been identified and indicate that anticholinergic agents, fatty foods, chocolate, alcohol, and cigarette smoking may have a harmful effect on a patient with heartburn. Drugs that increase the antireflux sphincter barrier have been studied. Clinical effectiveness of antacids and bethanechol in therapy of heartburn is supported by controlled treatment trials. Research continues on other medications producing increases in sphincter pressure.