Aj. Peixoto et Mn. Lassman, SEVERE HYPERPHOSPHATEMIA INDUCED BY A PHOSPHATE-CONTAINING ORAL LAXATIVE, The Annals of pharmacotherapy, 30(2), 1996, pp. 141-143
OBJECTIVE: To describe a case of severe hyperphosphatemia following un
intentional overdosage with an oral phosphate laxative, and raise atte
ntion to the risks of using such medications in the elderly. CASE SUMM
ARY: An 84-year-old white woman was admitted with confusion 8 hours af
ter inadvertently ingesting 12 fluid ounces of Fleet Phospho-Soda (ins
tead of the prescribed 1 1/2 fluid ounces) prior to a colonoscopy. Her
serum phosphate and ionized calcium concentrations were 10.3 mmol/L a
nd 0.56 mmol/L, respectively. She was treated conservatively with oral
phosphate binders and made an uneventful recovery. DISCUSSION: Severa
l previous reports have described hyperphosphatemia in association wit
h phosphate laxatives, especially in patients with renal or colonic di
sease. Our case again presents two important issues in the use of phos
phate laxatives by the elderly: (1) the frequently overlooked underlyi
ng renal insufficiency in which, despite ''normal'' serum creatinine v
alues, renal phosphate handling may be impaired; and (2) the potential
for drug misuse and poor compliance in the elderly. CONCLUSIONS: Caut
ion should be taken with the use of phosphate laxatives in the elderly
in the face of potentially serious metabolic abnormalities that may b
e generated.