Minoxidil® Toxicity in Cats

Did you know that Minoxidil® is very poisonous to cats? Minoxidil® is a topical solution used to promote hair growth in people. These medications have become very common and popular over the past 5 years.

According to the fall ASPCA newsletter, six cases involving Minoxidil® exposure were reported since 2001. Exposure ranged from cats accidentally walking through the spilled solution to owners actually applying medication to their pets in areas of hair loss. Of these cases, four of the cats died and two cats fully recovered after very aggressive treatment. Unfortunately, cats lack the specific enzyme necessary to break down this drug making them more susceptible to toxicity than dogs.

Minoxidil® exposure can result in lethargy, hypotension, pulmonary edema, damage to the heart muscle and death from cardiac failure. Initial signs of lethargy generally begin within 12 hours and heart damage occurs 3-4 days following exposure.

What to Watch For

• Lethargy
• Weakness
• Rapid respiratory rate
• Difficulty breathing
• Lack of appetite
• Coughing

Diagnosis

• The diagnosis is generally based on physical exam findings and a history of access or exposure to the drug.
• A blood pressure should be done to determine if your cat is hypotensive. Blood tests are often done to determine the overall health. If Minoxidil® was ingested; blood tests may reveal abnormal electrolyte concentrations, dehydration, or elevation in muscle enzymes. Repeat blood pressures and blood work may be recommended to determine ongoing organ damage and effectiveness of treatment.

Treatment

• Treatment is often symptomatic depending on the symptoms and condition of the pet.
• Expect your veterinarian to recommend hospitalization with continuous intravenous fluids.
• If medication was applied topically; medications should be washed of the paw or fur as soon as possible to prevent continued toxicity.
• Activated charcoal may be given if ingestion was recent.
• Drugs such as furosemide may be used to treat pulmonary edema. Additional drugs such as dopamine may be required to help maintain the blood pressure.

Prognosis

• The prognosis for Minoxidil® toxicity is guarded as it is highly toxic to cats. Aggressive treatment is indicated to treat this condition.

Home Care and Prevention

• There is no home care for Minoxidil® toxicity. Veterinary care is strongly recommended to treat severe lung and heart problems.
  While recovering from Minoxidil® toxicity, feed your cat often and encourage him or her to eat well. Watch for failure to eat, vomiting, difficulty breathing or lethargy.
• The best preventive care is to give your cat medications only if directed by your veterinarian. Medications that may be safe for people can be fatal to pets. Also, make sure that all medications are kept out of the reach of inquisitive pets. Keeping medicine safely stored away can prevent many tragedies.