Serum Electrolyte Shifts Following Administration of Sodium Phosphates Enema

Abstract

The misuse of sodium phosphates enemas has resulted in reports of potentially severe metabolic and hemodynamic disturbances. Despite their long availability, these products have not been fully characterized pharmacokinetically. This trial sought to evaluate changes in the metabolic and hemodynamic parameters following the administration of one of two standard sodium phosphates enemas. Enema Casen (250 ml) is available only in Spain, and Fleet Enema (133 ml) is available in 66 countries in six continents of the world. These changes were correlated with scientific literature reports of hyperphosphatemia following phosphate enema use. Forty-five adult participants aged 50 years or older enrolled in the trial. Twenty-five participants were given one Enema Casen, whereas 20 participants received one Fleet Enema. Blood pressure, pulse, and serum chemistries were evaluated at screening; baseline; and 10, 60, and 120 minutes after receiving the enema. Each participant had a bowel movement within 10 minutes of receiving his enema. Asymptomatic, transient hyperphosphatemia was associated with increase in retention time but not with increase in volume of sodium phosphates enemas. Increased serum phosphate concentration and increased area under the curve of serum phosphate were associated with increased enema retention time. The Enema Casen induced a greater mean AUC of serum sodium concentration than did the Fleet Enema. There were no drug-related adverse events. Transient hyperphosphatemia following the use of sodium phosphates enemas correlates with retention time but not with dose. A scientific literature review of serious adverse events revealed that overdose, concomitant use of oral and rectal sodium phosphates products, and use in a contraindicated patient were associated with sodium phosphates enema and hyperphosphatemia.

Severe hyperphosphataemia and metabolic acidosis after administration of phosphate-containing enema in a 10-year-old girl – case report and review of literature

“…A literature review showed that complications after enemas are also more common in children with gastroenterological conditions; for example, Hirschsprung's disease [17]. Yet, most of the reported severe adverse events were because of overdose, simultaneous admission of oral and rectal laxatives, or other contraindications [18]. Our patient presents an extremely rare case of developing typical side effects with no coexisting conditions.…”

Toxicity of phosphate enemas – an updated review

“…The volume and formulation of enema had no additional impact on this relationship. All serum calcium concentrations remained in the normal range (2.12-2.64 mmol/L; 8.5-10.6 mg/dL) [30].…”

“…Two studies [29,30] evaluated a Spanish phosphate enema preparation, Enema Casen (250 mL, containing 35.5 g monobasic sodium phosphate monohydrate and 17.8 g dibasic sodium phosphate dodecahydrate; a total of 304 mmol phosphate). The first compared the effects of Enema Casen with no treatment in a cross-over study in 24 volunteers aged 35-70 years [29].…”

“…The second study on the Spanish product [30] compared the effect of two phosphate enema formulations, a standard monobasic sodium phosphate monohydrate (133 mL of Fleet enema, containing $184 mmol phosphate) and Enema Casen [30] in an open-label study. These enemas contain approximately the same quantity of total anhydrous phosphate per mL.…”

The Risks of Phosphate Enemas in Toddlers: A Life-Threatening Unawareness

“…In the past, it had been erroneously postulated that phosphate contained in an enema was poorly absorbed, underestimating the fact that retention times may count even more than the absolute dose [ 37 , 38 ].…”