Identifying and Treating Vitamin A Toxicity in Cats

Vitamin A has several important functions in cats and if their diets do not contain the required amounts, they will suffer from various deficiency symptoms. However, it should be given in moderate amounts as excess amounts are associated with toxicity and other symptoms.

During our discussion on how much vitamin A cats need, its roles and deficiency signs, we stated that they require about 63 micrograms per an adult cat weighing about 9 pounds that consumes averagely 250 calories each day.

Alternatively, when buying feeds, they should have about 9000 IU of vitamin A per one kilogram of the feed and give them the recommended food amounts.

Otherwise, if they have too much of this vitamin, they may suffer toxicity and other signs of oversupply or suffer from deficiencies if the amount is not enough. This post focuses on vitamin A poisoning or toxicity.

Vitamin A poisoning in cats
Vitamin A poisoning in cats


The primary cause of this poisoning is giving your feline friend excessive amounts of foods or food supplements with high amounts of vitamin A. For instance, diets that are high in foods such as liver, fish liver oil or other organ meats may be a reason.

According to, “dietary intake exceeding 60,000 IU/kg body weight/day of vitamin A may be a cause. The normal dietary amounts should be 300 IU/ kg body weight.

Secondly, although this toxicity can affect cats of any age, there has been reported a higher prevalence in those that are aged between 2 to 9 years.

Finally, on a similar note, there seems a variation in how susceptible different cats are to this poisoning with some able to consume higher amounts without showing any symptoms.

Signs and symptoms

In most cases, signs and symptoms might be noted after a long period, such as months or years. However, younger cats may show signs and symptoms after a month or two.

When affected, usually, your pet will have joint bone spurs or exostosis (a new bone being formed on another bone surface) as well as cervical ankylosis where cervical bone joints become immobile and stiff as bones fuse. Ankylosis can happen to other bone joints including the limb and neck bone joints.

Also, this animal may suffer from deformed cervical spondylosis. Research on Hypervitaminosis A and deformed cervical spondylosis of the cat concluded that excessive amounts of this vitamin resulted in this condition characterized by “lesions developing mainly at the first three diarthrodial joints of the cervical vertebrae.”

Common symptoms you may notice include the following:

  • Loss of appetite or anorexia
  • Weight loss
  • Constipation
  • Lethargy
  • A kangaroo-like sitting posture characterized by raised or stretched forelimbs
  • Lameness with stiff immobile joints including a stiff neck.
  • Poor fur quality and an unkempt cat due to its inability to groom as usual. Expect messy, matted and a lot of loose furs.
  • According to a Research Project at Utrecht University, alopecia and dermatitis may be noted in some cats.
  • Some may suffer from exophthalmia – eyes bulging out anteriorly.
  • Symptoms of pain especially if you try pick it or it hides for a long time may be noted in some cats. This will occur if there are growing bones that exert pressure and will it be chronic if this problem affects the spinal code.
  • Finally, catHealth notes that “kittens can also suffer from loose teeth, abnormal tooth development, and bone growth abnormalities.” Furthermore, they may not gain weight as expected.

If you note any of these symptoms, you should immediately have this animal checked by an experienced vet.


Your vet will ask you questions relating to the history this pet diet including supplements given, do a physical examination, urinalysis, and complete blood count to rule out other disease and conditions including anemia that show similar symptoms.

A complete blood count may indicate an increase in the number of white blood cells and blood biochemistry may also show if glucose levels are high.

Furthermore, radiographs may be used to detect bone spurs as well as cervical ankylosis or ankylosis of any other bone joints including those on the neck.

Finally, a more conclusive way to be certain that there is excessive vitamin A is through testing blood to detect their levels.

Hypervitaminosis A treatment and prognosis

Treatment option will depend on how serious the case is. It may include supportive care in case of permanent or irreversible bone malformation together with dietary changes where you will give your cat a balanced diet.

Any foods or supplements with vitamin A should be discontinued or reduced. Your vet will advise you accordingly. Make follow up testing to ensure the condition is getting better and to be certain that this vitamin is not becoming less than required.

Prognosis, on the other hand, will depend on how soon the problem is detected and the age of your cat. Adult or mature ones often recover unless there are permanent bone deformations.

Furthermore, your vet may prescribe medications to manage pain (anti-inflammatory medicines and painkillers) and consider surgical removal of any grown bones.

Finally, make littering boxes, food, and water easily accessible in case of mobility issues. Your cat should be able to access them with little movement. In case he or she looks unkempt, help in grooming him.


Always work with your vet in determining the right diet for your cats or if you intend to begin supplementing any diet. Furthermore, take your feline friend for blood tests to determine levels of vitamin A in their blood at regular intervals.

Secondly, go for high-quality foods from reputed manufactures because not all of them accurately determine the amount of vitamin A present in their feeds.

Remember too little of the vitamin will cause deficiencies while too much will cause poisoning alongside other symptoms.

See also

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