IDENTIFICATION AND USE: Sodium phosphate dibasic and sodium phosphate monobasic combination is used to clean or empty your bowels before an imaging procedure called colonoscopy. This medicine works by cleaning your colon and causing you to have diarrhea.

HUMAN EXPOSURE/TOXICITY: the FDA said it has become aware of reports of severe dehydration and changes in serum electrolyte levels from taking more than the recommended dose of OTC sodium phosphate products, resulting in serious adverse effects on organs, such as the kidneys and heart, and in some cases resulting in death.

“The predominant electrolyte disturbances were hyperphosphatemia, hypocalcemia, and hypernatremia,” the FDA said.

The problem surfaced in a review of the agency’s Adverse Event Reporting System database and the medical literature, which turned up 54 cases in 25 adults and 29 children of serious adverse events associated with the oral or rectal use of OTC sodium phosphate drug products used to treat constipation, the FDA said.

“According to the reports, most cases of serious harm occurred with a single dose of sodium phosphate that was larger than recommended or with more than 1 dose in a day,” the FDA said.

USE WITH CAUTION: individuals who may be at higher risk for potential adverse events when the recommended dose of OTC sodium phosphate is exceeded include young children; individuals older than 55 years; patients who are dehydrated; patients with kidney disease, bowel obstruction, or inflammation of the bowel; and patients who are using medications that may affect kidney function.

ADVERSE EFFECTS: allergic reaction: itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing, blood in your urine, lower back pain, side pain, or sharp back pain just below your ribs, confusion, weakness, and muscle twitching, decrease in how much or how often you urinate, dizziness or fainting, dry mouth, increased thirst, muscle cramps, nausea or vomiting, fast, pounding, or uneven heartbeat, red or black stools, seizures, severe stomach pain, nausea, vomiting, or bloating.