Laxative abuse

Efficacy and safety of elobixibat in hemodialysis patients with chronic constipation: a retrospective study

Background

Hemodialysis patients are likely to develop constipation as a complication due to food and fluid restrictions. Elobixibat is a new laxative that inhibits the ileal bile acid transporter expressed in the terminal ileum, suppresses bile acid reabsorption, increases the amount of bile acid flowing into the colon lumen, and promotes water secretion in the colon and colon motility. In this study, we examined the efficacy and safety of elobixibat in maintenance hemodialysis patients with chronic constipation.

Methods

In a study conducted on maintenance hemodialysis patients with chronic constipation, comparisons were conducted retrospectively based on constipation symptoms such as the frequency of spontaneous bowel movements before elobixibat treatment and 12 weeks after the administration of elobixibat, as well as based on blood electrolyte levels.

Results

The study was conducted on 23 patients, 19 of whom were subjected to treatment efficacy analysis. The frequency of spontaneous bowel movements was 2.0 ± 0.7 times/week before administration of elobixibat and reached 4.9 ± 2.3 times/week after 12 weeks of administration. The increase started after 1 week of treatment. Elobixibat treatment improved the constipation score (baseline, 10.4 ± 3.2; after 12 weeks, 5.7 ± 3.2), the Bristol Stool Form Scale (baseline, 2.2 ± 1.0; after 12 weeks, 4.2 ± 0.7), and patient satisfaction regarding defecation (baseline, 2.9 ± 0.9; after 12 weeks, 1.7 ± 1.1). The interdialytic weight gain (IDWG) was 5.68 ± 0.82% before initiation of treatment and decreased to 4.54 ± 1.34% after 12 weeks. The serum inorganic phosphorus (IP) levels were 5.68 ± 1.25 mg/dL and decreased to 4.93 ± 1.10 mg/dL after 12 weeks.

Conclusions

Elobixibat was effective in improving constipation symptoms in maintenance hemodialysis patients with chronic constipation. Elobixibat also improved dialysis-related laboratory test results, such as a decrease in serum IP levels and IDWG.

Trial registration

UMIN Clinical Trials Registry, UMIN000037285, retrospectively registered

Cyclic AMP-induced K+ secretion occurs independently of Cl- secretion in rat distal colon

cAMP induces both active Cl(-) and active K(+) secretion in mammalian colon. It is generally assumed that a mechanism for K(+) exit is essential to maintain cells in the hyperpolarized state, thus favoring a sustained Cl(-) secretion. Both Kcnn4c and Kcnma1 channels are located in colon, and this study addressed the questions of whether Kcnn4c and/or Kcnma1 channels mediate cAMP-induced K(+) secretion and whether cAMP-induced K(+) secretion provides the driving force for Cl(-) secretion. Forskolin (FSK)-enhanced short-circuit current (indicator of net electrogenic ion transport) and K(+) fluxes were measured simultaneously in colonic mucosa under voltage-clamp conditions. Mucosal Na(+) orthovanadate (P-type ATPase inhibitor) inhibited active K(+) absorption normally present in rat distal colon. In the presence of mucosal Na(+) orthovanadate, serosal FSK induced both K(+) and Cl(-) secretion. FSK-induced K(+) secretion was 1) not inhibited by either mucosal or serosal 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34; a Kcnn4 channel blocker), 2) inhibited (92%) by mucosal iberiotoxin (Kcnma1 channel blocker), and 3) not affected by mucosal cystic fibrosis transmembrane conductance regulator inhibitor (CFTR(inh)-172). By contrast, FSK-induced Cl(-) secretion was 1) completely inhibited by serosal TRAM-34, 2) not inhibited by either mucosal or serosal iberiotoxin, and 3) completely inhibited by mucosal CFTR(inh)-172. These results indicate that cAMP-induced colonic K(+) secretion is mediated via Kcnma1 channels located in the apical membrane and most likely contributes to stool K(+) losses in secretory diarrhea. On the other hand, cAMP-induced colonic Cl(-) secretion requires the activity of Kcnn4b channels located in the basolateral membrane and is not dependent on the concurrent activation of apical Kcnma1 channels.

Does hypokalaemia cause nephropathy? An observational study of renal function in patients with Bartter or Gitelman syndrome

BACKGROUND

Hypokalaemic nephropathy has been described in patients with chronic potassium depletion; it is a condition in which proximal tubular vacuolization and interstitial fibrosis occur, resulting in a decline in glomerular filtration rate (GFR) and, in some cases, renal failure. It has been described in patients with chronic diarrhoea, eating disorders, laxative abuse and primary hyperaldosteronism; also occasionally in Bartter syndrome (BS), in which severe hypokalaemia accompanies significant renal sodium and water losses, though rarely in Gitelman syndrome (GS), in which there is equally severe hypokalaemia, but only modest sodium losses.

AIM

We hypothesized that hypokalaemic nephropathy may not be due to potassium depletion per se, but persistently elevated circulating levels of aldosterone, possibly with superimposed episodes of renal hypoperfusion.

DESIGN AND METHODS

We searched UK and European data sets to retrospectively compare serum and urinary parameters in patients with GS and BS.

RESULTS

The patients with GS often had lower serum potassium concentrations than patients with BS, but the BS patients had significantly higher serum creatinine concentrations and lower estimated GFRs (eGFR). BS patients had significantly higher fractional excretions of sodium compared with GS patients, as well as higher plasma renin activities and serum aldosterone levels.

CONCLUSION

These findings show that in genetically confirmed cases of BS and GS, the degree of hypokalaemia (as an index of chronic potassium depletion) does not correlate with GFR, and that on-going sodium and water losses, and consequent secondary hyperaldosteronism, may play a more important role in the aetiology of hypokalaemic nephropathy.

Laxative abuse: epidemiology, diagnosis and management

Laxatives have been used for health purposes for over 2000 years, and for much of that time abuse or misuse of laxatives has occurred. Individuals who abuse laxatives can generally be categorized as falling into one of four groups. By far the largest group is made up of individuals suffering from an eating disorder such as anorexia or bulimia nervosa. The prevalence of laxative abuse has been reported to range from approximately 10% to 60% of individuals in this group. The second group consists of individuals who are generally middle aged or older who begin using laxatives when constipated but continue to overuse them. This pattern may be promulgated on certain beliefs that daily bowel movements are necessary for good health. The third group includes individuals engaged in certain types of athletic training, including sports with set weight limits. The fourth group contains surreptitious laxative abusers who use the drugs to cause factitious diarrhoea and may have a factitious disorder. Normal bowel function consists of the absorption of nutrients, electrolytes and water from the gut. Most nutrients are absorbed in the small intestine, while the large bowel absorbs primarily water. There are several types of laxatives available, including stimulant agents, saline and osmotic products, bulking agents and surfactants. The most frequently abused group of laxatives are of the stimulant class. This may be related to the quick action of stimulants, particularly in individuals with eating disorders as they may erroneously believe that they can avoid the absorption of calories via the resulting diarrhoea. Medical problems associated with laxative abuse include electrolyte and acid/base changes that can involve the renal and cardiovascular systems and may become life threatening. The renin-aldosterone system becomes activated due to the loss of fluid, which leads to oedema and acute weight gain when the laxative is discontinued. This can result in reinforcing further laxative abuse when a patient feels bloated and has gained weight. Treatment begins with a high level of suspicion, particularly when a patient presents with alternating diarrhoea and constipation as well as other gastrointestinal complaints. Checking serum electrolytes and the acid/base status can identify individuals who may need medical stabilization and confirm the severity of the abuse. The first step in treating laxative misuse once it is identified is to determine what may be promoting the behaviour, such as an eating disorder or use based on misinformation regarding what constitutes a healthy bowel habit. The first intervention would be to stop the stimulant laxatives and replace them with fibre/osmotic supplements utilized to establish normal bowel movements. Education and further treatment may be required to maintain a healthy bowel programme. In the case of an eating disorder, referral for psychiatric treatment is essential to lessen the reliance on laxatives as a method to alter weight and shape.

Altered cryptal expression of luminal potassium (BK) channels in ulcerative colitis

Decreased sodium (Na(+)), chloride (Cl(-)), and water absorption, and increased potassium (K(+)) secretion, contribute to the pathogenesis of diarrhoea in ulcerative colitis. The cellular abnormalities underlying decreased Na(+) and Cl(-) absorption are becoming clearer, but the mechanism of increased K(+) secretion is unknown. Human colon is normally a K(+) secretory epithelium, making it likely that K(+) channels are expressed in the luminal (apical) membrane. Based on the assumption that these K(+) channels resembled the high conductance luminal K(+) (BK) channels previously identified in rat colon, we used molecular and patch clamp recording techniques to evaluate BK channel expression in normal and inflamed human colon, and the distribution and characteristics of these channels in normal colon. In normal colon, BK channel alpha-subunit protein was immunolocalized to surface cells and upper crypt cells. By contrast, in ulcerative colitis, although BK channel alpha-subunit protein expression was unchanged in surface cells, it extended along the entire crypt irrespective of whether the disease was active or quiescent. BK channel alpha-subunit protein and mRNA expression (evaluated by western blotting and real-time PCR, respectively) were similar in the normal ascending and sigmoid colon. Of the four possible beta-subunits (beta(1-4)), the beta(1)- and beta(3)-subunits were dominant. Voltage-dependent, barium-inhibitable, luminal K(+) channels with a unitary conductance of 214 pS were identified at low abundance in the luminal membrane of surface cells around the openings of sigmoid colonic crypts. We conclude that increased faecal K(+) losses in ulcerative colitis, and possibly other diseases associated with altered colonic K(+) transport, may reflect wider expression of luminal BK channels along the crypt axis.

Gastrointestinal complaints in patients with eating disorders

BACKGROUND

Patients with eating disorders (EDs) typically have numerous somatic and gastrointestinal complaints. Early referral to treatment may result in improved outcomes. We sought to determine whether patients with EDs were presenting to gastroenterologists or primary care physicians with gastrointestinal complaints early in the disease course, when referral for specialized, comprehensive treatment would be most beneficial.

STUDY

Over a 1-year period, we administered a structured interview to a cohort of patients presenting for inpatient ED treatment. We also conducted the same interview on an age-matched cohort of medical students to determine baseline incidences of various gastrointestinal healthcare behaviors.

RESULTS

Patients with bulimia nervosa were significantly more likely to seek healthcare for a gastrointestinal complaint before seeking treatment for an ED than were controls. Patients with EDs were significantly more likely to be prescribed medication for the gastrointestinal tract than were controls.

CONCLUSION

Gastroenterologists and primary care physicians should employ available instruments to screen young women of low to normal weight with gastrointestinal complaints for possible EDs. Referral to specialized treatment programs should be made promptly when an ED is identified.

Myths and misconceptions about chronic constipation

There are many strongly held beliefs about constipation that are not evidence based. The purpose of this review is to address these beliefs concerning various aspects of constipation. There is no evidence to support the theory that diseases may arise via "autointoxication," whereby poisonous substances from stools within the colon are absorbed. Dolichocolon, defined as an elongated colon, should not be seen as a cause of constipation. The role of sex hormones altering gut function during the menstrual cycle appears to be minimal. During pregnancy they may play a role in slowing gut transit. Hypothyroidism can cause constipation, but among patients presenting with constipation, hypothyroidism is rare. A diet poor in fiber should not be assumed to be the cause of chronic constipation. Some patients may be helped by a fiber-rich diet but many patients with more severe constipation get worse symptoms when increasing dietary fiber intake. There is no evidence that constipation can successfully be treated by increasing fluid intake unless there is evidence of dehydration. In the elderly constipation may correlate with decreased physical activity, but many cofactors are likely to play a role. Intervention programs to increase physical activity as part of a broad rehabilitation program may help. It is unlikely that stimulant laxatives at recommended doses are harmful to the colon. A proportion of patients with chronic constipation is dependent of laxatives to achieve satisfactory bowel function, but this is not the result of prior laxative intake. Tolerance to stimulant laxatives is uncommon. There is no indication for the occurrence of "rebound constipation" after stopping laxative intake. While laxatives may be misused, there is no potential for addiction.

Adverse effects of laxatives

Laxatives are among the most commonly used drugs or additives. Most are quite safe when used judiciously, intermittently when possible, and in the absence of contraindications. Bulking agents and nonabsorbable compounds such as lactulose can cause bloating but have very few serious adverse effects except for the allergic reaction to psyllium preparations. Osmotic laxatives containing poorly absorbable ions such as magnesium or phosphate can cause metabolic disturbances, particularly in the presence of renal impairment. However, if taken intermittently, in the absence of conditions such as ileus or bowel obstruction, they have few adverse effects. Polyethylene glycol solutions are emerging as an effective and safe mode of treatment for chronic constipation. Of stimulant laxatives, senna compounds and bisacodyl are the most commonly used. Although there are data to support the neoplastic potential of this class of drugs in in vitro studies, epidemiologic data in humans so far has not established a clear link between these laxatives and colonic neoplasia. The link between stimulant laxatives and structural changes, such as the "cathartic colon" or enteric nerve damage, is not well established either. Danthron compounds should be avoided because of hepatotoxicity.

Detection, evaluation, and treatment of eating disorders the role of the primary care physician

OBJECTIVE

To describe how primary care clinicians can detect an eating disorder and identify and manage the associated medical complications.

DESIGN

A review of literature from 1994 to 1999 identified by a MEDLINE search on epidemiology, diagnosis, and therapy of eating disorders, including anorexia nervosa and bulimia nervosa.

MEASUREMENTS AND MAIN RESULTS

Detection requires awareness of risk factors for, and symptoms and signs of, anorexia nervosa (e.g., participation in activities valuing thinness, family history of an eating disorder, amenorrhea, lanugo hair) and bulimia nervosa (e.g., unsuccessful attempts at weight loss, history of childhood sexual abuse, family history of depression, erosion of tooth enamel from vomiting, partoid gland swelling, and gastroesophageal reflux). Providers must also remain alert for disordered eating in female athletes (the female athlete triad) and disordered eating in diabetics. Treatment requires a multidisciplinary team including a primary care practitioner, nutritionist, and mental health professional. The role of the primary care practitioner is to help determine the need for hospitalization and to manage medical complications (e.g., arrhythmias, refeeding syndrome, osteoporosis, and electrolyte abnormalities such as hypokalemia).

CONCLUSION

Primary care providers have an important role in detecting and managing eating disorders.

Review article: anthranoid laxatives and their potential carcinogenic effects

Anthranoid laxatives are widely used laxatives of natural origin. Because of their chemical structure they are carried unabsorbed to the large bowel, where metabolism to the active aglycones takes place. These aglycones exert their laxative effect by damaging epithelial cells, which leads directly and indirectly to changes in absorption, secretion and motility. Damaged epithelial cells can be found as apoptotic bodies in the pigmented colonic mucosa, characteristic for pseudomelanosis coli. Pseudomelanosis coli is a condition caused by chronic (ab)use of anthranoid laxatives and has recently been associated with an increased risk of colorectal carcinoma. In vitro and animal studies have shown a potential role of anthranoid laxatives in both the initiation and promotion of tumorigenesis. Studies in humans have also suggested tumour promoting activities for these laxatives. Although the short-term use of these substances is generally safe, long-term use cannot be recommended.

Congestive cardiac failure following laxative withdrawal

We report the case of a 60-year-old woman who presented with weakness and hypokalaemia due to excessive use of laxatives. When the laxatives were withdrawn, she developed severe congestive cardiac failure requiring treatment with a diuretic and angiotensin-converting enzyme inhibitor. There was no underlying cardiac abnormality, and these drugs were eventually stopped with no recurrence of the cardiac failure. The possible mechanisms of heart failure following laxative withdrawal is discussed.

Complications of laxative abuse

Laxative abuse is an uncommon but clinically important cause of chronic diarrhea, a condition often associated with other gastrointestinal symptoms, as well as with disturbances in electrolyte and acid-base balance. A high index of suspicion, a detailed history, and the detection of laxative in stool and/or urine will establish the diagnosis once routine laboratory, endoscopic, and radiologic investigations have excluded common causes of chronic diarrhea. Confirmation of the diagnosis may rule out the need for more extensive, invasive, and costly investigations. However, management is frequently difficult owing to the laxative abuser's complex underlying psychopathology.

Incidence of laxative abuse in community and bulimic populations: a descriptive review

Estimates of the incidence of laxative abuse in bulimics and in the community-at-large vary widely for various population samples. This review identified 73 studies in which laxative abuse could be assessed in bulimics, nonbulimics, and the community-at-large. Relative risk values for laxative abuse among population subsamples were estimated by moment methods statistical procedure based on mixed model analysis. Results indicated that the lifetime occurrence for laxative abuse behavior in the community-at-large was 4.18%. Bulimic behavior increased the risk for laxative abuse 3.57-fold to 14.94%. Several methodologic and population parameter characteristics are examined for their select impact on laxative abuse. Review of medical nomenclature for classifying laxative substances, iatragenic effects of laxative abuse, and assessment recommendations are also included.

Laxative Induced Diarrhoea-A Neglected Diagnosis

A laxative screening service was established and offered to gastroenterologists in hospitals covering the West and Central belt of Scotland. The prevalence of laxative induced diarrhoea was assessed in two populations and was found to be 4% in new patients presenting to a gastroenterology clinic with diarrhoea and 20% in patients already under investigation of chronic idiopathic diarrhoea. A high rate of missed diagnosis of laxative induced diarrhoea (71%) and a low request rate (eight per annum) confirm the low clinical awareness of this diagnosis. We found potential savings of 80% of the cost of investigations subsequently ordered which could have been avoided by performing laxative screens on all patients presenting with diarrhoea. The introduction of such a screening policy is recommended as a cost-effective measure.

Abuse of drugs associated with eating disorders

Concomitant bulimia nervosa and drug abuse are common in women. Drugs used by this group include diuretics, emetics, laxatives, and diet pills, as well as alcohol, cigarettes, and illicit street drugs. This paper applies principles from behavioral pharmacology to the problem of drug use by women with bulimia nervosa. The prevalence of use, primary effects, toxicity, detection, tolerance, withdrawal, and effects on appetite and weight are discussed for drugs used by bulimic women to reduce appetite or weight or to induce purging (e.g., diuretics, emetics, laxatives, and diet aids). Alternatives in the diagnosis and treatment of drug use in women with eating disorders are discussed.

Drug-induced colonic pseudo-obstruction. Report of a case

Colonic pseudo-obstruction may have many possible causes. Some of these are well described and pose no diagnostic problems. Drug-related colonic pseudo-obstruction remains underreported, but is of importance in modern society where drugs are endemically abused. This case highlights the importance of drugs in altering colonic motility and emphasizes the nonsurgical management of this condition.

The effect of poorly absorbed solute on intestinal absorption

To determine the effects of poorly absorbed solute on intestinal absorption, the urinary recovery of ingested lactulose, L-rhamnose, D-xylose, and 3-O-methyl-D-glucose was measured after simultaneous ingestion of various 'loads' of mannitol given in iso-osmolar solution. Mannitol reduced intestinal uptake of the poorly absorbed test sugars, lactulose and L-rhamnose; uptake of D-xylose and 3-O-methyl-D-glucose, which are absorbed by carrier-mediated transport largely from the jejunum, was less affected. The dose-response effect of mannitol on the absorption of L-rhamnose was approximately exponential; doses of 5, 10, and 20 g mannitol reduced the average urinary excretion of L-rhamnose by 34.7%, 51.7%, and 61.2%, respectively. In this respect, an osmotically equivalent load of lactulose, ingested as 'solute', was approximately twice as effective as mannitol in reducing L-rhamnose absorption, probably because lactulose is more poorly absorbed than mannitol (less than 1.0% versus 32-41%). Ingestion of other poorly absorbed solutes such as raffinose, sorbitol, xylitol, magnesium sulphate, and sodium sulphate also significantly depressed the absorption of L-rhamnose; in contrast, more efficiently absorbed solutes, such as sodium chloride, glucose, glycerol, and urea had little effect.

Microbially controlled drug delivery to the colon

The human gastrointestinal tract consists of a highly complex ecosystem of aerobic and anaerobic microorganisms that plays a significant role in the metabolism of nutrients as well as drugs. In the colon, bacteria ferment various types of substrates that are not susceptible to digestion in the small intestine. This arouses interest in specific drugs, drug delivery systems, and prodrugs that escape small bowel digestion, arrive intact, and are absorbed or degraded in the large bowel. For the past forty years, experience has been gained with the azo prodrug of 5-amino salicylic acid, salazopyrine, which is cleaved by colonic bacteria to its parent drug. Some laxative drugs were also reported to degrade into active metabolites in the colon. Lately equally interesting and more sophisticated microbial controlled delivery systems, have been developed based on similar principles.

Drug prescribing in residential homes for elderly people in the United Kingdom

Data relating to the use of medicines from a descriptive epidemiologic study of drug use in 55 residential homes for elderly people in Britain were analyzed. Of the 1888 residents included in the study, 1617 (85.6 percent) received a total of 5535 medicines. The median number of medicines received per day was three and the per-day range varied from one to thirteen medicines. Significantly more women than men received medicines and women also received more medicines each. The most frequently prescribed group of medicines were those acting on the central nervous (34.0 percent), the cardiovascular (27.2 percent), and on the gastrointestinal (8.9 percent) systems. Deficiencies were identified in doses, duration, and selection of drugs in certain therapeutic groups.

Resistance of myenteric neurons in the rat's colon to depletion by 1,8-dihydroxyanthraquinone

Earlier reports have suggested that anthraquinone purgatives in excessive amounts cause degeneration of neurons in the enteric nervous system. Danthron (1,8-dihydroxyanthraquinone) was administered to rats in their drinking water for four months. The effects of the drug on the total number of neurons and on the immunoreactivity of eight putative neurotransmitters in the myenteric plexus of the colon have been assessed. No differences were found between the treated animals and their controls, indicating that the drug does not kill myenteric neurons. These results agree with recent observations on the effects of senna in rats and mice, and do not support earlier claims that myenteric neurons are killed by anthraquinone purgatives.

Treatment of laxative abuse in a female with bulimia nervosa using an operant extinction paradigm

Chronic laxative abuse was treated using an operant extinction paradigm in a 29-year-old woman with bulimia nervosa. Access to self-administration of laxative and placebo were alternated in an ABAB design. Outcome was measured by self-reported craving for laxatives and rates of drug self-administration. During baseline, the subject exhibited high rates of both craving and self-administration. During placebo phases, cravings and drug self-administration declined. Both measures increased when active drug was reinstated. The final return to placebo led to a decrease in craving and extinction of drug self-administration to zero doses per day. This paper introduces the concept of laxatives as reinforcers and provides a new approach to the treatment of laxative abuse in women with bulimia nervosa.

Prevalence of surreptitious laxative abuse in patients with diarrhoea of uncertain origin: a cost benefit analysis of a screening procedure

The costs and medical benefits of an early, routine laxative screening test in patients with diarrhoea of uncertain origin was evaluated. During a two year period 200 consecutive, unselected patients complaining of diarrhoea were considered for the study in whom a three day faecal collection was undertaken. Fifty four patients denying laxative consumption had diarrhoea (mean daily stool weight greater than 200 g) of uncertain origin at their initial visit of whom 47 were screened to detect ingestion of anthraquinones, bisacodyl, phenolphthalein, and magnesium salts. Seven patients had positive tests. No single clinical feature could have predicted the outcome of the test. The possible cost savings of the programme were estimated by not releasing the results of the test to the clinicians until the patient's investigations were complete. The seven patients with laxative abuse spent a total of 35 days in hospital and were seen on 29 occasions in the outpatient clinic after the laxative screening test was positive. The cost of the screening programme was cheaper than the costs of the diagnostic procedures in patients with laxative abuse. We recommend the use of a comprehensive, early laxative screening programme in all patients with diarrhoea of uncertain origin as a cost effective procedure.

Sennosides do not kill myenteric neurons in the colon of the rat or mouse

Effects of senna on the myenteric plexus of the colon were investigated in view of earlier reports that this anthraquinone cathartic depletes the plexus of its intrinsic neurons. Rats and mice were given purgative doses of sennosides in their drinking water for 4 and 5 months, respectively. Body growth was reduced, and the weight of the colon with its contents was increased relative to the weight of the whole body in the treated animals. The latter change was attributed to depressed propulsive motility of the large intestine. Total numbers of myenteric neurons were determined from whole-mount preparations stained with Cuprolinic Blue-magnesium chloride, which selectively coloured the neuronal somata. The number of neurons in the rat's colon was unaffected by treatment with senna, but the colons of the treated mice contained significantly more neurons than those of their controls. Staining with antisera to 10 putative neurotransmitters or their associated enzymes revealed immunoreactive somata and axons in the myenteric plexus. Treatment with senna was not associated with absence of neuronal somata or fibres stainable with any of the antisera in either species. Thus, there was no evidence of toxic destruction of any identifiable population of neurons that might have been too small to affect the total counts. We conclude that senna does not kill myenteric neurons in the colon of the rat or mouse.

Screening procedure for stimulant laxatives in urine using high-performance liquid chromatography with diode array detection

We describe a liquid chromatographic screening procedure for the detection of stimulant laxatives in urine. A 2-ml urine sample was incubated with 500 U of beta-glucuronidase for 2 h at 60 degrees C. The sample was acidified with sodium acetate (pH 5.0) and extracted with 5 ml of an isopropanol-chloroform (1:9) mixture. The organic layer was cleaned up further by washing with 5 ml disodium hydrogen-phosphate (pH 7.5) before being transferred to a conical tube and evaporated to dryness. The residue was reconstituted in 100 microliters mobile phase and 3 microliters were injected onto a Hewlett-Packard Hypersil ODS (5 microns) column. The ultraviolet absorbance of the eluent was monitored at 225 nm. Rhein, bisacodyl diphenol, bisoxatin diphenol, phenolphthalein, bisacodyl, bisoxatin and danthron all eluted within 6 min. The screen was evaluated using urine specimens obtained from 19 patients who claimed they had taken one or more of the laxatives under consideration within the past 48 h. Only two patients who claimed to have taken Coloxyl and Danthron showed negative results. Eighteen of twenty laxatives (90%) taken by the patients were detected and their identity verified by plotting post-run ultraviolet spectra. We therefore conclude that the screen is sufficiently reliable to be of help in the early detection of surreptitious abusers of stimulant laxatives.

Melanosis coli. Ultrastructural study of 45 patients

Melanosis coli was diagnosed histologically in colon biopsies of 45 patients with prolonged administration of anthraquinone laxatives. Colonoscopies performed for increased constipation, abdominal pains, or distention disclosed discoloration of the mucosa in only 14 patients. Radiographic studies revealed motility disorders of the colon. In several cases, a circular stenosis occurred at the junction of the colon and the sigmoid, simulating a tumor. Electron microscopy showed abnormalities of the absorptive epithelial cells. The lamina propria contained pigment-laden macrophages, plasma cells, and several nerve fibers in different stages of degeneration. The most striking changes of autonomic nerve elements occurred in patients with the most serious motility disorders.

Stimulation of PGE2 synthesis and water and electrolyte secretion by senna anthraquinones is inhibited by indomethacin

The effect of dried senna pod extract, containing 10% sennoside B, on colonic electrolyte and fluid transport was examined in the anaesthetized rat in-situ. Oral administration of senna pod extract dose-dependently (17.5-30 mg kg-1, calculated as sennoside B) reversed net absorption of water, sodium and chloride to net secretion and increased potassium secretion. Senna pod extract stimulated the output of prostaglandin E2 into the colonic lumen. Inhibition of prostaglandin biosynthesis by pretreatment of the rats with indomethacin (10 mg kg-1) significantly inhibited the effects of senna pod extract (17.5-30 mg kg-1) both on net fluid transport and on prostaglandin E2 synthesis. The inhibitory effect of indomethacin on net fluid transport induced by senna pod extract (30 mg kg-1) was dose-dependent. It is concluded that anthraquinones exert their laxative action at least partially via stimulation of colonic fluid and electrolyte secretion, and that this secretion is mediated by stimulation of endogenous prostaglandin E2 formation.

Influence of chronic bisacodyl treatment on the effect of acute bisacodyl on water and electrolyte transport in the rat colon

Excessive or unnecessary taking of laxatives leads to a vicious circle with perpetuation of laxative abuse and increase of laxative dosage, accompanied by severe clinically evident disturbances. It was investigated in rats whether chronic administration of bisacodyl reduces the effects of acute bisacodyl administration on net water and electrolyte flux in the rat colon transport in-vivo. After chronic pretreatment with bisacodyl had been given for 21 days (3 mg and 10 mg kg-1 day-1), net water and sodium absorption was found to be decreased whereas potassium secretion was increased. After 21 days of pretreatment, the effect of acute bisacodyl (10 micrograms ml-1 intraluminal) on net water and sodium transport was reduced whereas the effect on potassium secretion remained unchanged. Serum and erythrocyte levels of sodium and potassium remained unchanged in chronically pretreated rats. Serum aldosterone levels were enhanced two fold. It is concluded that under the experimental conditions described, chronically administered bisacodyl leads to elevated serum aldosterone which counteracts the effect of bisacodyl on net water and sodium transport but acts synergistically with bisacodyl on the effect on potassium loss.

Severe idiopathic constipation is associated with a distinctive abnormality of the colonic myenteric plexus

We analyzed the clinical, radiographic, esophageal manometric, and pathologic features of 26 women with severe, idiopathic constipation. Twenty-four patients were between 19 and 39 yr of age. Stool frequency was once every 5-28 days. On barium enema examination, 9 of 24 patients had colons of increased length and 4 of these 9 patients had colons of increased width (greater than 10 cm). Radionuclide solid-meal gastric-emptying studies were normal in 23 patients tested. Esophageal manometry demonstrated high-amplitude waves in 10 of 22 patients and long-duration waves in 3 of these 10 patients. Rectal biopsy specimens showed normal submucosal neurons in all patients and melanosis coli in 6. Twelve patients underwent subtotal colectomies for constipation. Conventional light microscopy using hematoxylin and eosin serial sections showed (a) melanosis coli in 4 patients; (b) normal smooth muscle in 11; (c) thinning of the circular muscle in 1; and (d) no apparent abnormalities of the myenteric plexus in any. In contrast, silver stains of the myenteric plexus showed (a) quantitatively reduced numbers of argyrophilic neurons in 10 patients; (b) morphologically abnormal argyrophilic neurons in 11; (c) decreased numbers of axons in 11; and (d) increased numbers of variably sized nuclei within ganglia in all 12. A coded analysis of the silver stains of colons from 8 patients with constipation and 19 control cases demonstrated that the pathologic abnormalities of severe idiopathic constipation could be differentiated from controls. Thus, severe idiopathic constipation is associated with a pathologically identifiable abnormality of the myenteric plexus. This abnormality appears different from anything previously described in intestinal pseudoobstruction.

Coma and neuropathy after ingestion of herbal laxative containing podophyllin

A case of poisoning caused by an excessive dose of herbal laxative tablets is reported. The patient's symptoms included coma and prolonged peripheral neuropathy. The clinical features were characteristic of podophyllin poisoning. Podophyllin was a component of the laxative tablets, but the container gave no indication of their potential toxicity. Methods of reducing the risk of inadvertent poisoning by herbal remedies are suggested.

Antacids and laxatives for symptomatic relief in the elderly

Guidelines for the safe, effective use of antacids and laxatives are presented, with emphasis on the special problems and considerations of their use in the elderly. Discussed are properties affecting drug selection, dosage, measures to ensure compliance, adverse reactions, and drug interactions. Physician--patient dialogs are recommended, as is patient education about the dangers of inappropriate or excessive use of these products, and the need to obtain medical care for unremitting symptoms.

Case report. Tumoral calcinosis: an unusual complication of the laxative abuse syndrome

A 47-year-old woman who abused laxatives as a means of weight control is described. Her laxative abuse resulted in an episode of tetany for which she was given long-term calcium and vitamin D therapy. This therapy, along with the ingestion of absorbable phosphate and alkali, and large amounts of milk, led to the development of tumoral calcinosis. The failure to fully appreciate the contribution of laxative abuse in her metabolic imbalance resulted in this complication.

The fine structure of colonic submucosal nerves in patients with chronic laxative abuse

Ultrastructural studies of colonic biopsies from patients with a history of long-term laxative abuse, predominantly with stimulant cathartics such as anthraquinone derivatives or bisacodyl, indicated that submucosal nerve fibres may be severely damaged in relation to dosage and time of addiction. The main pathological features found were ballooning of axons, reduction of nerve-specific cell organelles, lysosomal activity, and increase of melanin-loaded macrophages. Morphometric analysis revealed a significant increase (P less than 0.01) in axonal area, with simultaneous reduction of neurotubules. Nerve endings showed a significant decrease of neurosecretory granules when compared with those of normals. It is concluded that these alterations might be a morphological correlation to the clinically evident disturbance of gut motility in patients with chronic laxative abuse, because the intact enteric plexus system is a prerequisite for coordination of normal gut peristalsis.

Review of laxative utilization in a skilled nursing facility

Laxatives are the most frequently prescribed drugs in long-term care facilities. Of all nursing home patients, 58 percent receive laxatives--often more than one, and usually on a "prn" basis. This pattern of dosage is probably used in an effort to prevent constipation. Selection of a laxative should be based on careful evaluation of the cause of constipation, with due consideration being given to differences in drug effectiveness and the incidence of side effects. A review of laxative utilization among 73 elderly patients in a large metropolitan skilled nursing facility showed a rational use of these drugs. However, more attention should have been paid to the dietary management of constipation.

Drug-induced gastrointestinal disease

Clinicians administering potent therapeutic agents must be aware of their side-effects. The gut is an important site of adverse drug reactions and drug-induced disease must always be considered in the differential diagnosis of patients presenting with gastrointestinal symptoms. A careful drug history must therefore be taken in all such patients. Symptoms can often be related to drug ingestion, but late effects also occur. The presence of blood in vomitus or stool is pathognomonic of serious pathology which may be drug-induced and requires further investigation. Upper gastrointestinal haemorrhage and pseudomembranous colitis are potentially fatal manifestations of drug therapy. Gastrointestinal symptoms can often be avoided if therapy is taken with meals or in a smaller dose, but drug withdrawal is always the first line of management in patients whose symptoms may be drug-induced.