October 2014

Fleet enema toxicity in cats and dogs

By Dr. Justine Lee, DVM, DACVECC, DABT

When it comes to feline rectums, cat owners should leave them alone.

That’s because even the most well intentioned pet owner may accidentally use a Fleet enema to treat their constipated cat, not knowing how toxic it is. Likewise, rare toxicity can occur when veterinarians (who didn’t read the ingredients carefully on the enema) use them in their patients.

Certain types of enemas – particularly FLEET enemas or SALINE enemas are deadly to cats and small dogs. Even one Fleet enema (or anything containing phosphate, sodium phosphate, or saline) can be deadly to cats and small dogs.

Another important consideration? Normal, healthy, hydrated cats don’t get constipated. It’s those with underlying disease like megacolon or diseases that predispose them towards dehydration (e.g., acute kidney injury, where their kidneys aren’t filtering effectively resulting in inappropriate free water loss and secondary pu/pd and dehydration or diabetes mellitus, where they have an osmotic diuresis). These diseases predispose these patients to dehydration and potentially make them more at risk for dehydration.

So why are Fleet enemas toxic?

Because they increase the osmolality in the colon, which draws more free water into the colon to equilibrate the ionic load (hence, making the stool softer and relieving the constipation). Unfortunately, this results in severe toxicity.

Clinical signs and clinicopathologic findings of toxicity from Fleet enemas include:Fleet enema toxicity in cats VetGirl

  • Malaise
  • Vomiting
  • Severe dehydration
  • Hypernatremia
  • Hyperphosphatemia
  • Hypocalcemia
  • Hypokalemia
  • Weakness
  • Bloody diarrhea
  • Acute death

Typically, it’s too late to decontaminate these patients. We don’t decontaminate them orally (as they received the toxicant rectally) and the use of activated charcoal is not recommended (as it may exacerbate the hypernatremia). Warm water enemas can be administered (via red rubber catheter) to help remove any remaining Fleet enema, if  the pet owner gave the Fleet enema within the past few hours.

Treatment should be aimed at correcting the electrolytes via aggressive intravenous (IV) fluid therapy. The use of 2-2.5X maintenance is often required, provided the patient doesn’t have cardiopulmonary disease. Frequent monitoring of electrolytes (every 4-8 hours) is necessary. The use of phosphate binders can also be considered (e.g., aluminum hydroxide) to help minimize further gastrointestinal absorption of phosphorous.  Remember: 90% of P (Phosphorous) is GI absorbed and 90% is renally excreted.

The most important thing to note about treatment? DO NOT TREAT THE HYPOCALCEMIA unless the patient is severely symptomatic from the hypocalcemia. Why? Because remember the formula: TOTAL Ca X P > 70 = mineralization of the soft tissue? As these patients are already hyperphosphatemic, you are potentially contributing to mineralization, which can result in secondary acute kidney injury (AKI). Unless the patient is twitching, seizuring, or tremoring, severely hypocalcemic, or persistently hypotensive, the use of calcium supplementation generally should be avoided with this toxicity.

Thankfully, with aggressive supportive care, electrolyte monitoring, potassium supplementation and fluid therapy, most of these patients are treatable. In general, hospitalization for 24-72 hours is necessary to treat Fleet enema toxicity. When in doubt, contact ASPCA Animal Poison Control Center for further information.

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Copyright VETgirl, 2014.

  1. thank you for this info. My added question would be what kind of enemas are used in felines, if any at all. Or would the vet use a mineral oil or soapy warm water mix.. I’m writing a paper. 🙂 Thanks again.

  2. I think you should be more specific which fleet products shouldn’t be used because fleet also makes qlycerin Products that of used correctly aren’t harmful. They actually have the same ingredients as the OTC feline enemas. There are prob a lot of people that read this because it was the first link that popped up when I searched feline enemas.

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