Administration of sodium phosphate products prior to colonoscopy
for colon cleansing has resulted in fatalities due to significant fluid shifts,
severe electrolyte abnormalities, and cardiac arrhythmias. These fatalities have
been observed in patients with renal insufficiency, in patients with bowel
perforation, and in patients who misused or overdosed sodium phosphate products.
It is recommended that patients receiving OsmoPrep be advised to adequately
hydrate before, during, and after the use of OsmoPrep.
Considerable caution should be advised before OsmoPrep Tablets are used in
patients with the following illnesses: severe renal insufficiency (creatinine
clearance less than 30 mL/minute), congestive heart failure, ascites, unstable
angina, gastric retention, ileus, acute bowel obstruction, pseudo-obstruction of
the bowel, severe chronic constipation, bowel perforation, acute colitis, toxic
megacolon, gastric bypass or stapling surgery, or hypomotility syndrome.
Consider performing baseline and post-colonoscopy labs (phosphate, calcium,
potassium, sodium, creatinine, and BUN) in patients who may be at increased risk
for serious adverse events, including those with history of renal insufficiency,
history of-or at greater risk of-acute phosphate nephropathy, known or suspected
electrolyte disorders, seizures, arrhythmias, cardiomyopathy, prolonged QT,
recent history of a MI and those with known or suspected hyperphosphatemia,
hypocalcemia, hypokalemia, and hypernatremia. Also if patients develop vomiting
and/or signs of dehydration then measure post-colonoscopy labs (phosphate,
calcium, potassium, sodium, creatinine, and BUN).
Renal Disease, Acute Phosphate Nephropathy, and
Electrolyte Disorders
There have been rare, but serious, reports of renal failure,
acute phosphate nephropathy, and nephrocalcinosis in patients who received oral
sodium phosphate products (including oral sodium phosphate solutions and
tablets) for colon cleansing prior to colonoscopy. These cases often resulted in
permanent impairment of renal function and several patients required long-term
dialysis. The time to onset is typically within days; however, in some cases,
the diagnosis of these events has been delayed up to several months after the
ingestion of these products. Patients at increased risk of acute phosphate
nephropathy may include patients with the following: hypovolemia, baseline
kidney disease, increased age, and patients using medicines that affect renal
perfusion or function [such as diuretics, angiotensin converting enzyme
(ACE)inhibitors, angiotensin receptor blockers, and possibly nonsteroidal
anti-inflammatory drugs (NSAIDs).
Use OsmoPrep with caution in patients with impaired renal function, patients
with a history of acute phosphate nephropathy, known or suspected electrolyte
disturbances (such as dehydration), or people taking concomitant medications
that may affect electrolyte levels (such as diuretics). Patients with
electrolyte abnormalities such as hypernatremia, hyperphosphatemia, hypokalemia,
or hypocalcemia should have their electrolytes corrected before treatment with
OsmoPrep Tablets.
Seizures
There have been rare reports of generalized tonic-clonic seizures
and/or loss of consciousness associated with use of sodium phosphate products in
patients with no prior history of seizures. The seizure cases were associated
with electrolyte abnormalities (e.g., hyponatremia, hypokalemia, hypocalcemia,
and hypomagnesemia) and low serum osmolality. The neurologic abnormalities
resolved with correction of fluid and electrolyte abnormalities. OsmoPrep should
be used with caution in patients with a history of seizures and in patients at
higher risk of seizure [patients using concomitant medications that lower the
seizure threshold (such as tricyclic antidepressants), patients withdrawing from
alcohol or benzodiazepines, or patients with known or suspected
hyponatremia].
Cardiac Arrhythmias
There have been rare, but serious, reports of arrhythmias
associated with the use of sodium phosphate products. OsmoPrep should be used
with caution in patients with higher risk of arrhythmias (patients with a
history of cardiomyopathy, patients with prolonged QT, patients with a history
of uncontrolled arrhythmias, and patients with a recent history of a myocardial
infarction). Pre-dose and post-colonoscopy ECGs should be considered in patients
with high risk of serious, cardiac arrhythmias.
