Mucosal irritant potential of a potassium-sparing diuretic and of wax-matrix potassium chloride

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.

Antihypertensive drugs and the risk of gastrointestinal bleeding

PURPOSE

Calcium channel blockers have been reported to increase the risk of gastrointestinal bleeding. We tested this hypothesis, and also assessed whether beta blockers decrease this risk.

SUBJECTS AND METHODS

A nested case-control design within a population-based cohort of all 34,074 new users of beta blockers, angiotensin-converting enzyme (ACE) inhibitors, or calcium channel blockers in Saskatchewan, from 1990 to 1993 and followed up to March 1995, was used. We identified all 311 subjects hospitalized because of gastrointestinal bleeding during this period, each of whom was matched to 10 randomly selected controls.

RESULTS

The rate of hospitalization for gastrointestinal bleeding was 3.0 per 1,000 per year. The adjusted rate ratio of gastrointestinal bleeding for current use of calcium channel blockers was 1.1 (95% confidence interval [CI] 0.8 to 1.4) and 0.66 (95% CI 0.44 to 0.98) for beta blockers compared with no current use of anti-hypertensive drugs. The adjusted rate ratio for ACE inhibitor use was 1.0 (95% CI 0.7 to 1.3) while that for diuretic use was 1.4 (95% CI 1.0 to 2.0).

CONCLUSIONS

The use of calcium channel blockers does not appear to increase the risk of gastrointestinal bleeding in the first five years of treatment, while beta blockers may prevent this adverse event. The unexpected elevated risk associated with the use of diuretics needs to be investigated further.

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.

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.