Vinca Poisoning in Cats

What separates the Vinca rosea (now Catharanthus roseus) from other periwinkles is the presence of some very strong alkaloids including vincristine and vinblastine. These toxins are actually harvested from the plant for their effective use in chemotherapy, which in itself is a monitored form of poisoning the body. If a cat were to consume the plant, adverse effects could follow. Vinca has both cytotoxic and hypoglycemic properties, capable of causing disruption to the function of cells, severe blistering and lowered blood pressure. If large quantities are ingested, liver failure is possible. 

Some know it as Madagascar periwinkle, others as running myrtle, but either way, vinca is a powerful and beautiful plant. While it is native to Madagascar, this fast spreading ground cover can grow in many of the warmer regions of the United States. Vinca spreads by rhizomes, similar to the way that grass grows. In some areas, this speedy growth has lead to the plant being listed as invasive. The flowers of the vinca range from light pinks to dark fuschias, and are often the reason that this plant is used in landscaping. The leaves of the vinca are oval in shape and have a glossy appearance. The plant may grow in a shrub form, reaching up to 3 feet in height.

Gastrointestinal upset following consumption of the vinca plant is the most common symptom that arises. In extreme scenarios, brain and central nervous system issues may be noted, although this is rare. All signs to watch for include:

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Bloating
• Constipation
• Depression
• Fever
• Low blood pressure
• Cardiac abnormalities
• Central nervous system issues
• Tremors
• Seizures
• Coma

Vinca is generally found outdoors. It is often used as a ground covering in people's gardens, but may also be found growing in the wild due to its invasive nature. Some may keep the plant potted indoors for its showy display of bright pink flowers. Most cats are discouraged from sampling any more than one bite, as the plant has a very bad taste. 

If you have witnessed your cat eating vinca, or if adverse symptoms have begun to arise, take it in to be looked at by a professional. If severe symptoms are compromising the cat's vital functions, the episode should be treated as an emergency. Once you have arrived at a veterinary clinic or animal hospital, you will likely be asked to provide the cat's full medical history. This can help the veterinarian identify what is wrong with the cat and also what types of complications may develop during treatment. You will likely be asked if you allow your cat outdoors and what kind of plants you keep in your home and gardens. 

The veterinarian will then perform a complete physical examination of the cat to note all symptoms that have developed. Vital signs will be measured, which may reveal abnormally low blood pressure and a high temperature, indicating fever in the cat. The vet may use a stethoscope to listen to the breathing and heart rate of the cat. Irregular heart rhythms may be noted at this point. A sample of the cat's blood will be needed so that routine tests may be run, including a complete blood count (CBC) and a biochemical profile. The results of these tests may show depleted electrolytes, which is a sign of dehydration. Urinalysis may be performed to assess if liver damage has occurred.

No effective antidote for vinca poisoning has been found as of yet. This means that treatment will revolve around the symptoms that develop in the cat. Treatment may need to begin before a diagnosis has been made in some instances.

Remove Plant Material 

The cat's oral cavity will be flushed with water to remove all remaining bits of plant material. The vet may choose to induce the cat to vomit, emptying the stomach of its contents. If the cat is not in a stable state, gastric lavage (stomach pumping) may be chosen over emesis.

Medication 

Certain medications may be administered to ease the irritation of the stomach. Kapectolin or sucralfate may be used, as they both line the stomach from its contents.

Supportive Care 

Depending on the severity of the cat's condition, hospitalization may be required while the cat is enduring the illness. During this time the heart may need to be monitored and intravenous fluids with electrolytes may have to be administered.

As most cats will only ingest a small amount, the majority will recover after gastrointestinal symptoms have passed. In the rare event that large amount of plant material has been consumed, permanent liver damage, a weakened immune system, and even death may result from the poisoning. If your cat has recently recovered from such a poisoning, it may be best to avoid certain medications and vaccinations for some time.