Upper gastrointestinal lesions after potassium chloride supplements: a controlled clinical trial

Concomitant oral potassium chloride and anticholinergic therapy is associated with upper gastrointestinal bleeding: A cohort study

AIM

To determine whether oral potassium chloride (KCI) therapy with concomitant anticholinergic exposure among hospitalized patients is associated with an excess risk for upper gastrointestinal bleeding (UGIB).

METHODS

A retrospective controlled study among hospitalized patients between January 2007 and April 2019 who were treated with oral KCI. Patients were divided into two groups: with or without concomitant exposure to agents with anticholinergic activity. Outcome was defined as any UGIB.

RESULTS

The final sample included 13 728 subjects who received oral KCI treatment, of them 3542 (25.8%) had at least one documented overlap with an anticholinergic agent. Mean age was 67.6 (±17.2) and 6893 (50.2%) were females. Median KCI dose was 2.4 g (interquartile range [IQR] 1.2-5.4, n = 9416) with the majority (90.4%) being treated with the wax-matrix form (Slow-K). Twenty-six (0.2%) patients experienced an UGIB event. Univariate analysis demonstrated a significantly higher rate of UGIB among patients concomitantly treated with oral KCI and anticholinergics (0.3%) compared to those without anticholinergic exposure (0.1%, P = 0.018), with median 7 days (IQR 3-16.8) from first KCI dose to bleeding event. Multivariate analysis demonstrated that concomitant anticholinergic exposure (Odds Ratio 2.48, 95% Confidence Interval 1.11-6.51, P = 0.022) and anticoagulation treatment among patients with hemato-oncologic disease (OR 6.61, 95% CI 1.96-22.25, P = 0.002) were significantly associated with UGIB.

CONCLUSION

Hospitalized patients treated concomitantly with oral KCI and anticholinergic agents have significantly increased risk for UGIB.

Development and evaluation of taste masked dry syrup formulation of potassium chloride

Potassium chloride (KCl) syrup is widely used for the oral treatment of the hypokalemia. However, it is associated with unacceptable taste. In the present study, we sought to develop a palatable and easy to reconstitute KCl dry syrup as a commercially viable alternative to currently available KCl syrup. We explored the potential of Eudragit E100 as a taste-masking polymer to coat and improve the palatability of the KCl. With the help of fluid bed processor, KCl was coated with the solution containing varying amounts of Eudragit E100 (4, 6, 10 and 15%). Coating with 10% polymer solution enabled optimal fluid bed processing, higher entrapment of the KCl (81%) and better in vitro release profile in 0.1 N HCl and pH 6.8 phosphate buffer. A dry syrup formulation containing Eudragit E100 coated KCl with good physical and chemical stability in dry and reconstituted state was developed. The palatability of the optimized formulation and commercially available KCl syrup was evaluated using the Electronic Taste Sensing Machine. The developed formulation showed~ 2-fold better taste-masking compared to the commercial KCl syrup. Thus, present investigation describes the development of an effective alternative to the current KCl syrup that can offer better palatability, stability and patient compliance.

Risk factors associated with lower defecation frequency in hospitalized older adults: a case control study

BACKGROUND

Constipation is highly prevalent in older adults and may be associated with greater frequency of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). We investigated the prevalence of lower defecation frequency (DF) and risk factors (including AECOPD) associated with lower DF among hospitalized elderly patients.

METHODS

We conducted a retrospective case-control study in a community hospital of Southeast Ohio. Adults aged 65 years or older admitted during 2004 and 2006 were reviewed (N = 1288). Patients were excluded (N = 212) if their length of stay was less than 3 days, discharge diagnosis of Clostridium difficile-associated diarrhea, death or ventilator- dependent respiratory failure during hospitalization. Lower DF was defined as either an average DF of 0.33 or less per day or no defecation in the first three days of hospitalization; cases (N = 406) and controls (N = 670) were included for the final analysis.

RESULTS

Approximately 38% had lower DF in this patient population. Fecal soiling/smearing of at least two episodes was documented in 7% of the patients. With the adjustment of confounders, AECOPD (adjusted odds ratio [AOR] =1.47, 95% confidence interval [CI] =1.01-2.13) and muscle relaxant use (AOR =2.94; 95% CI =1.29-6.69) were significantly associated with lower DF. Supplementation of potassium and antibiotic use prior to hospitalization was associated with lower risk of lower DF.

CONCLUSIONS

Approximately 38% of hospitalized older adults had lower DF. AECOPD and use of muscle relaxant were significantly associated with lower DF; while supplementation of potassium and antibiotic use were protective for lower DF risk after adjusting for other variables.

Indomethacin, amiloride, or eplerenone for treating hypokalemia in Gitelman syndrome

Patients with Gitelman syndrome (GS), an inherited salt-losing tubulopathy, are usually treated with potassium-sparing diuretics or nonsteroidal anti-inflammatory drugs and oral potassium and magnesium supplementations. However, evidence supporting these treatment options is limited to case series studies. We designed an open-label, randomized, crossover study with blind end point evaluation to compare the efficacy and safety of 6-week treatments with one time daily 75 mg slow-release indomethacin, 150 mg eplerenone, or 20 mg amiloride added to constant potassium and magnesium supplementation in 30 patients with GS (individual participation: 48 weeks). Baseline plasma potassium concentration was 2.8±0.4 mmol/L and increased by 0.38 mmol/L (95% confidence interval [95% CI], 0.23 to 0.53; P<0.001) with indomethacin, 0.15 mmol/L (95% CI, 0.02 to 0.29; P=0.03) with eplerenone, and 0.19 mmol/L (95% CI, 0.05 to 0.33; P<0.01) with amiloride. Fifteen patients became normokalemic: six with indomethacin, three with eplerenone, and six with amiloride. Indomethacin significantly reduced eGFR and plasma renin concentration. Eplerenone and amiloride each increased plasma aldosterone by 3-fold and renin concentration slightly but did not significantly change eGFR. BP did not significantly change. Eight patients discontinued treatment early because of gastrointestinal intolerance to indomethacin (six patients) and hypotension with eplerenone (two patients). In conclusion, each drug increases plasma potassium concentration in patients with GS. Indomethacin was the most effective but can cause gastrointestinal intolerance and decreased eGFR. Amiloride and eplerenone have similar but lower efficacies and increase sodium depletion. The benefit/risk ratio of each drug should be carefully evaluated for each patient.

Preclinical Assessment of Gastrooesophageal Tolerance of the New Antiosteoporotic Drug Strontium Ranelate: An Endoscopic Study in Monkeys

This study was aimed at evaluating the digestive tolerance of the new antiosteoporotic drug, strontium ranelate, and to compare it to that of another strontium salt, strontium chloride (SrCl2). Strontium ranelate, SrCl2, or placebo were administered orally (capsules) to 3 groups of 2 male and 2 female cynomolgus monkeys (Macaca fascicularis) once a day for 7 days at a dose of 2 g/day, which is the recommended therapeutic dose in man. Endoscopic examination of the oesophagus, the stomach and the first part of the duodenum was performed on fasted animals approximately 3 hr after the first (Day 1) and last dosing (Day 7), and, on Day 8 and Day 14 in case of lesions on Day 7. Strontium ranelate did not induce any acute or subchronic toxic effect on the gastric mucosa, the oesophagus and the first part of the duodenum. On the contrary, acute and superficial damages were noted on all animals receiving SrCl2 such as haemorrhagic and erosive lesions (formation of an ulcer in one male and a marked congestive antritis in one female). These effects were reversible after cessation of treatment. The microscopic examination of biopsies sampled at the site of gastric lesions revealed moderate granulocyte infiltration, indicating a local irritating origin of the lesions. Strontium ranelate by oral route is safe for the gastric mucosa while SrCl2 induced superficial and reversible lesions.

Treatment of nephrogenic diabetes insipidus with hydrochlorothiazide and amiloride

Nephrogenic diabetes insipidus (NDI) is characterised by the inability of the kidney to concentrate urine in response to arginine vasopressin. The consequences are severe polyuria and polydipsia, often associated with hypertonic dehydration. Intracerebral calcification, seizures, psychosomatic retardation, hydronephrosis, and hydroureters are its sequelae. In this study, four children with NDI were treated with 3 mg/kg/day hydrochlorothiazide and 0.3 mg/kg/day amiloride orally three times a day for up to five years. While undergoing treatment, none of the patients had signs of dehydration or electrolyte imbalance, all showed normal body growth, and there was no evidence of cerebral calcification or seizures. All but one had normal psychomotor development and normal sonography of the urinary tract. However, normal fluid balance was not attainable (fluid intake, 3.8-7.7 l/m2/day; urine output, 2.2-7.4 l/m2/day). The treatment was well tolerated and no side effects could be detected. Prolonged treatment with hydrochlorothiazide/amiloride appears to be more effective and better tolerated than just hydrochlorothiazide. Its efficacy appears to be similar to that of hydrochlorothiazide/indomethacin but without their severe side effects.

Pill-induced gastric injury

Pill-induced esophageal injury is a well described clinical entity. In contrast, pill-induced gastric injury has not been well characterized. In this report, we describe two patients with acute gastric ulcers due to pill ingestion and review the available literature on pill-induced gastric injury. The first patient presented with upper gastrointestinal hemorrhage and was found to have a large gastric ulcer with multiple potassium chloride pills in the ulcer crater. The second patient presented with odynophagia and endoscopy revealed doxycycline-induced esophageal and gastric injury. To our knowledge, this is the first case report of doxycycline-induced gastric ulcer.

Effect of potassium-magnesium citrate on upper gastrointestinal mucosa

BACKGROUND

Potassium supplements may cause mucosal damage of the gastrointestinal tract.

AIM

To evaluate the effect of a new potassium supplement, potassium-magnesium citrate (K-Mag), on upper gastrointestinal mucosa and to compare it with an older potassium supplement, potassium citrate (Urocit-K).

METHODS

A randomized and double-blind study was conducted utilizing 36 healthy adults. Subjects were randomized into three groups: K-Mag (70 mmol/day K, 35 mmol/day citrate and 17.6 mmol/day Mg); Urocit-K (70 mmol/day K and 23.4 mmol/day citrate), and placebo. All subjects took 5 tablets b.d. of the allocated drug and 2 mg t.d.s. of glycopyrrolate for 7 days. On day 8, stool was examined for occult blood, a symptom score was calculated and an oesophagogastroduodenoscopy was performed. Mucosal lesions were scored at five anatomic sites.

RESULTS

Demographic characteristics and symptom score were similar in the three groups (< 10% with more than mild symptoms). There were no significant differences in the endoscopic scores at any site examined nor in the total scores among the three groups. Erosion or ulcers were found in 180% of K-Mag, 23% of Urocit-K and 17% of the placebo group.

CONCLUSION

Short-term use of K-Mag does not appear to induce lesions in the upper gastrointestinal mucosa and its oral tolerance is similar to Urocit-K or placebo.

What is the better formulation of microencapsulated potassium chloride?

A single blind cross-over study was performed comparing a new microencapsulated potassium chloride tablet (MET) with two reference formulations of oral potassium, namely potassium chloride solution (PS), and microencapsulated potassium chloride capsules (MEC), in 18 normal healthy volunteers. The potassium chloride induced change in gastric potential difference (PD) of the mucosa was the main criterion of comparison and was assessed by the area above curve (AAC), the total duration of the effect (TDE), the maximal variation of PD (delta MAX), and the aggression index (AI). The results showed that all three formulations induced a fall in PD; the delta MAX and AAC were significantly greater for PS indicating a higher aggressive effect of the solution; MET had significantly less aggressive effect than MEC when assessed by all parameters.

Side effects of nonsteroidal anti-inflammatory drugs on the small and large intestine in humans

BACKGROUND

It is not widely appreciated that nonsteroidal anti-inflammatory drugs (NSAIDs) may cause damage distal to the duodenum. We reviewed the adverse effects of NSAIDs on the large and small intestine, the clinical implications and pathogenesis.

METHODS

A systematic search was made through Medline and Embase to identify possible adverse effects of NSAIDs on the large and small intestine.

RESULTS

Ingested NSAIDs may cause a nonspecific colitis (in particular, fenemates), and many patients with collagenous colitis are taking NSAIDs. Large intestinal ulcers, bleeding, and perforation are occasionally due to NSAIDs. NSAIDs may cause relapse of classic inflammatory bowel disease and contribute to serious complications of diverticular disease (fistula and perforation). NSAIDs may occasionally cause small intestinal perforation, ulcers, and strictures requiring surgery. NSAIDs, however, frequently cause small intestinal inflammation, and the associated complications of blood loss and protein loss may lead to difficult management problems. The pathogenesis of NSAID enteropathy is a multistage process involving specific biochemical and subcellular organelle damage followed by a relatively nonspecific tissue reaction. The various possible treatments of NSAID-induced enteropathy (sulphasalazine, misoprostol, metronidazole) have yet to undergo rigorous trials.

CONCLUSIONS

The adverse effects of NSAIDs distal to the duodenum represent a range of pathologies that may be asymptomatic, but some are life threatening.

Effect of meal on the physiological and physicochemical actions of potassium citrate

The effect of meals on the physiological and physicochemical actions of potassium citrate was examined in 8 patients with nephrolithiasis maintained on a constant metabolic dietary regimen. Potassium citrate (20 mEq. 3 times per day), whether given with food or on an empty stomach, significantly increased urinary pH, citrate and potassium, and decreased urinary calcium and ammonium. Moreover, potassium citrate decreased urinary saturation of calcium oxalate and uric acid, although it slightly increased that of brushite. However, there was no significant difference in these measures when the drug was given with meals from the time when it was given on an empty stomach. Thus, the effect of potassium citrate on urinary risk factors is unaffected by food.

A comparison of wax matrix and microencapsulated potassium chloride in relation to upper gastrointestinal illness requiring hospitalization

The frequency of hospitalization for documented upper gastrointestinal illness among recipients of either wax matrix or microencapsulated potassium chloride was similar in a study in which clinics were randomly assigned to dispense one or the other preparation. The results indicate that there is no material difference between the two preparations in relation to serious upper gastrointestinal illness.

Bioavailability of potassium from three dosage forms: suspension, capsule, and solution

A crossover study was performed in 28, healthy, male volunteers to determine the bioavailability of potassium from a suspension containing microencapsulated potassium chloride compared with that from a marketed microencapsulated potassium chloride capsule and a marketed potassium chloride solution. The 20-day study consisted of four, five-day periods. In three of the periods, a single, 40-mEq dose of one of the potassium formulations was administered; no drug treatment was given in the remaining period so that the amount of potassium contributed by dietary sources could be determined. Meals were served that provided controlled amounts of potassium and sodium. Bioavailability was represented by cumulative amount of K+ excreted in urine 24 and 48 hours after drug administration. The rate of absorption was calculated from excretion rates during each of the intervals of urine collection on Days 4. The pattern of excretion exhibited by the solution indicated rapid absorption and elimination. The potassium from the suspension and the capsules was excreted more slowly and over a longer period, indicating that the potassium content from these formulations was not being dumped. No statistically significant differences between the suspension and the capsules were found. The extent of absorption of K+ was similar from all three products, and the potassium from the suspension was found to be fully bioavailable when compared with the liquid and the capsule.

Subepithelial hemorrhages and erosions of human stomach

Subepithelial hemorrhages and erosions of the stomach are being studied extensively in experimental animal models but have not been well-characterized in humans. The definitions of these hemorrhagic and erosive lesions are not uniform and are often further confused by being labeled with the blanket term "gastritis." We define these lesions from an endoscopic perspective, describe the clinical settings in which they occur, and provide endoscopic-histologic correlations, where available.

Assessment and validation of animal models to evaluate topical effects of substances on gastrointestinal mucosa

The in situ rabbit colon model is a sensitive and reproducible test to evaluate the topical effect of up to three substances applied to the colonic mucosa. Vibra-Tabs (doxycycline hyclate), Inderal (propranolol hydrochloride), and Slow-K (potassium chloride) were compared for topical effects in the Carlborg-Densert cat esophagus model, the Alphin-Droppleman cat gastric mucosa model adapted for dog intestine, and the rabbit colon. Because results were comparable in all models, additional dosage formulations were subsequently tested only in the rabbit colon model. After exposure of the tissue to drugs, macroscopic and histologic effects were scored on four- and eight-point scales, respectively. In all three models, Vibra-Tabs and Inderal produced the highest macroscopic and histologic scores, although Slow-K was also irritating. In the rabbit colon model, potassium released from Slow-K and Micro-K Extencaps caused more irritation than from controlled-release GITS (KCl) (gastrointestinal therapeutic system KCl).

Gastroscopic localization of a microencapsulated KCl preparation in the human stomach

A slow release polymer-coated preparation of potassium chloride granules (Micro-K Extencaps) was initially thought not to be associated with gastric mucosal damage. Recent studies have shown that acute gastric ulcers occur with approximately the same frequency as in patients taking wax matrix KCl formulations. The development of acute gastric ulcers was not consistent with the proposed dispersion characteristics of the microencapsulated KCl preparation. The authors therefore endoscopically evaluated the dispersion characteristics of microencapsulated KCl in a double-blind, placebo-controlled study. Subjects received four capsules of Micro-K or matching placebo and endoscopy was performed 30, 60, or 120 min after each drug ingestion. The material was identified with the Olympus HM (high magnification) endoscope and then quantitatively aspirated using the 3.5-mm biopsy channel of the Pentax 34JA endoscope. Microencapsulated KCl particles dispersed poorly and were found adhering to the mucosa and to one another, as a semisolid mass, most frequently in the gastric antrum. In contrast, the placebo (ethyl cellulose) was widely dispersed throughout the stomach. The authors concluded that gastric emptying must be considered in three phases: liquids, solids, and solids which adhere to the mucosa. No unique dispersion characteristics of Micro-K Extencaps were identified, and adherence of the KCl to the gastric mucosa may explain its ability to cause occasional acute gastric ulceration.

Evaluation of the ulcerogenic effect of potassium chloride by endoscopy and fecal blood loss

In a blinded-observer crossover study, 16 volunteers ingested equimolar doses of three different potassium chloride preparations and placebo for nine days in a random order. The irritating effect on the mucosa was evaluated by means of upper gastrointestinal endoscopy and fecal blood loss, measured by reference to the amount of radioactivity in three 24-hour samples after previous injection of 51Cr-tagged autologous red cells. The microencapsulated KCl capsule preparation induced three ulcers, but the total endoscopic group score was not significantly higher than the score with placebo. The total endoscopic group score for the wax-matrix formulation was significantly higher than the score for placebo (P less than .05) and for a new microencapsulated KCl tablet preparation containing a potent disintegrant (P less than .10). We did not find any significant differences in mean fecal blood loss during the four different treatments. A correlation between endoscopic score and fecal blood loss was found in the placebo group (r = .54) and the microencapsulated KCl capsule preparation (r = .56) group.

Jejunal perforation possibly induced by slow-release potassium in a patient with Crohn's disease

A case of small bowel ulceration and perforation possibly due to therapy with Klotrix in a patient with Crohn's disease is presented. Following emergent surgery with creation of a diverting loop jejunostomy, subsequent reestablishment of intestinal continuity was carried out with excellent clinical results. Gastrointestinal mucosal lesions possibly due to wax-matrix potassium chloride preparations are reviewed.

Indiscretion enteritis. A Rabelaisian syndrome

A 76-year-old man had small bowel obstruction and organic small bowel disease following a series of bizarre massive gustatory insults that involved food, medications, and mega-mineral-vitamin supplements. Intestinal obstruction required partial small bowel resection. The dietary indiscretions resulted in severe enteritis (indiscretion enteritis). The sequence has been termed a Rabelaisian syndrome after the great French writer and physician, Francois Rabelais, who vividly described bizarre gustatory habits. Gut injury may result from unwise oral intake of various foods and mineral supplements.

The effect of oral potassium chloride on upper gastrointestinal mucosa in healthy subjects: healing of lesions despite continuing treatment

The effects of two dosage forms of wax-polymer matrix potassium chloride on the upper gastrointestinal mucosa were compared with placebo in 44 healthy volunteers. After 2 weeks of potassium chloride treatment, mucosal toxicity was observed. There was no correlation between the presence of lesions and symptoms. Six of seven volunteers with lesions healed spontaneously despite continuing treatment with potassium chloride.

Upper gastrointestinal endoscopy in normal asymptomatic volunteers

In a prospective study, 355 healthy, asymptomatic, male volunteers, 18 to 45 years of age, were screened by esophagogastroduodenoscopy before admission to clinical trials. One hundred thirty-four volunteers (38%) showed abnormal endoscopic findings. Some volunteers had more than one site of involvement or more than one grade of lesion in each anatomic location. In 49 (14%) of these subjects the esophagus was a site of involvement, while in 86 (24%) the stomach was involved, and in 71 (20%) the duodenum was involved. The point prevalences in these asymptomatic subjects were 8.5% for erosive esophagitis, 12% for erosive gastritis, 10% for erosive duodenitis, 2% for gastric ulcer, and 2% for duodenal ulcer.

Effects on upper gastrointestinal mucosa of three delivery systems of potassium as supplement to frusemide administration

Thirty healthy volunteers were recruited into a study to determine the effects on the gastrointestinal mucosa of 3 different delivery systems of oral potassium supplementation associated with diuretic therapy (Diumide-K ContinusR tablets, Napp; Lasikal tablets, Hoechst; Lasix and Slow-KR tablets, Hoechst, Ciba). The volunteers were gastroscoped initially and after one week of treatment with one of the three therapies. There was a 60% incidence of erosions in the Lasix + Slow-K group, a 40% incidence in the Lasikal group, but no erosions in the group receiving Diumide-K Continus tablets. It is therefore concluded that Diumide-K Continus tablets incorporate the potassium in a delivery system which is unlikely to cause disruption to the gastrointestinal mucosa.

Current approaches to management of potassium deficiency

Current issues related to oral potassium supplementation are reviewed, with emphasis on recommendations for the appropriate use of potassium supplementation for both replacement and preventive therapy. Dietary potassium intake, potassium-sparing diuretics, and the various forms of oral potassium supplements are reviewed in terms of indications for use, advantages, and limitations. Attention is given to controversial areas, i.e., gastrointestinal tolerance of controlled-release potassium oral dosage preparations and the need for potassium supplementation in hypertensive patients treated with diuretics.

Liquid and solid potassium chloride: bioavailability and safety

Studies have suggested that microencapsulated preparations of potassium chloride may pose less risk to the upper gastrointestinal mucosa than the currently available wax-matrix preparations. Based on our own clinical experience and data available from the literature, we have concluded that (1) liquid and slow-release preparations of potassium chloride are safe and effective when used appropriately and (2) at present there is no conclusive evidence to suggest that lesions of the upper gastrointestinal tract are more prevalent with one slow-release preparation than with another.

Potassium and the heart

The electrical stability of the heart is more sensitive to the extracellular than to the intracellular potassium concentration. During exercise, extracellular potassium varies rapidly. Catecholamines also modulate the plasma potassium concentration. Hypokalaemia of any cause can precipitate arrhythmias. Ischaemic myocardium loses potassium into the extracellular space within seconds and the cell becomes depolarized. The rise of the extracellular potassium ion concentration accounts for many of the early electrophysiological changes. Abrupt changes of plasma potassium concentration in normal myocardium and a high potassium concentration in ischaemic myocardium can set up electrical forces which initiate arrhythmias. The same phenomenon can account for changes on the electrocardiogram early after the cessation of an exercise test in a patient with ischaemic heart disease. Accumulation of potassium between cells in response to an increase of heart rate is a possible mechanism for false positive exercise tests and Syndrome X.

Irritative properties of two clinical potassium chloride formulations on duodenal mucosa of the cat and esophageal mucosa of the opossum

The local gastrointestinal irritating properties of microencapsulated KCl (M-E), a new and unique form of KCl (8 meq potassium per capsule), were compared with a wax-matrix (W-M) KCl formulation (8 meq potassium per tablet). Normal saline in 0-size gelatin capsules was used as the control substance. The comparisons were made in two animal models that simulate the condition of partial obstruction of the gastrointestinal tract in humans. These models are the duodenum of the cat and the esophagus of the opossum, each with a surgically created partial obstruction. The tissues were exposed to two capsules or tablets of KCl or saline for 4 hr, and the extent of tissue injury assessed by using a rating scale. The irritation caused by M-E was significantly (P less than 0.05) less than that caused by W-M in both the cat and the opossum, and it was not significantly (P greater than 0.05) different from the injury caused by saline in either model. The relative lack of irritation by M-E is probably explained by the fact that there was a significantly (P less than 0.05) greater dispersion of KCl from the M-E capsule than from the W-M tablet.

The effects of five potassium chloride preparations on the upper gastrointestinal mucosa in healthy subjects receiving glycopyrrolate

The effects on the upper gastrointestinal tract of five different preparations of KCl were compared in 90 healthy subjects treated with glycopyrrolate. The KCl preparations studied were wax-matrix KCl, microencapsulated KCl, liquid KCl, experimental extended-release capsules, experimental extended-release tablets,and placebo. The subjects were endoscoped prior to and after seven days of dosing. Upper gastrointestinal mucosal pathology was seen with all of the potassium preparations as well as with placebo. No statistically significant differences between the various KCl groups or between KCl groups and placebo were seen. All of the lesions were superficial, except for one ulcer seen with the microencapsulated KCl. None of the subjects developed occult gastrointestinal bleeding. There were no differences in the incidence of abdominal symptoms.

Pharmacokinetics of an oral frusemide/amiloride combination tablet

A randomized four-way crossover study was carried out in 12 healthy volunteers to investigate the pharmacokinetics of a new oral combination of frusemide (40 mg) and amiloride (5 mg), formulated as a single tablet. The experimental design of this bioequivalence study used commercially-available 40 mg frusemide tablets and 5 mg amiloride tablets as reference drugs, administered either separately or concomitantly. From a statistical analysis of plasma levels of frusemide and amiloride, no significant differences between the reference drugs alone and the combination tablet were seen in peak plasma levels, mean times to peak or mean areas under the plasma concentration-time curves (AUCs). The ratio of AUCs of the combination tablet to the reference drugs approached a limiting value many hours prior to complete elimination of the drug and hence reliable bioavailability comparisons were possible with blood sampling up to 24 hours post-dose.

Frusemide/amiloride combination ('Frumil') in heart failure: an open, multi-centre study in general practice

A total of 95 patients seen in general practice with oedema associated with heart failure took part in an open study of the efficacy and tolerability of a combination tablet containing 40 mg frusemide and 5 mg amiloride. The study was of 3-months' duration and patients received a dosage of 1 to 2 tablets once daily. Efficacy was assessed by physicians' scores for ankle, leg and lumbosacral oedema and pulmonary crepitations, body weight and physicians' global clinical impression. In addition, patients recorded their symptom severity in study diaries during the first 7 days of therapy, and the day before each trial visit. On the basis of the physicians' overall impression of response to therapy, 89 (93.7%) of the patients were graded as 'excellent', 'good' or 'adequate' responders. Improvement in severity scores for oedema, crepitations and body weight also followed this pattern, although certain symptoms were mild or absent in some patients at recruitment. Nine patients were withdrawn from the study, 4 due to drug-related adverse effects. There was no evidence of any consistent change in serum potassium levels or other clinical chemistry, liver function tests or haematology during the study.