Effect of potassium chloride supplements on upper gastrointestinal mucosa

Eight controlled 1- or 2-wk experiments involving 225 healthy male subjects and one study of 18 patients with hypertension, nine of whom were long-term users of a wax-matrix potassium chloride preparation, were conducted to evaluate the upper gastrointestinal safety of oral KCl supplements. All subjects in the short-term studies had normal upper gastrointestinal tracts. Subjects were examined again after at least 7 days of treatment with one of three commonly prescribed wax-matrix KCl tablets, KCl liquid, microencapsulated KCl, a potassium-sparer, or placebo. Some received an anticholinergic drug with treatment to induce delayed gastric motility. Diet and compliance to treatment regimens were controlled. Results indicate that upper mucosal injury, particularly erosions (43%) and ulcerations (11%), were more frequent after wax-matrix tablets. These changes occurred much less frequently after liquid KCl (0%), microencapsulated KCl (10.5% erosions, 1.2% ulcers), and the potassium-sparing drug (0%). More serious and more frequent lesions were associated with slowed motility. No occult bleeding was noted. Symptomatic complaints did not correlate with endoscopic findings. In the long-term study, patients with hypertension were examined endoscopically after 19 to 23 mo on KCl and again after 1 wk. Six of nine of the patients with hypertension treated for nearly 2 yr with a wax-matrix KCl supplement had significant lesions. One had developed ulceration after 7 days. The incidence of lesions was lower in a carefully matched group of controls who received only placebo (erosions in three of nine; none had or developed ulcers). Incidence of upper mucosal injury with wax-matrix tablets is higher than with other liquid or microencapsulated forms of KCl or with a potassium-sparing drug.