Running Myrtle Poisoning in Dogs

The running myrtle originates in Madagascar, Sri Lanka, and India. It is also common in South Africa and Australia, but in the United States it only grows well in warmer climates such as Florida, Mississippi, South Carolina, and Texas. This plant is an excellent ground cover, with short, glossy evergreen leaves and star-like blooms in shades of lilac, magenta, white, purple, and red. The running myrtle has over 100 toxic alkaloids that can be dangerous if ingested by your dog. Some of these alkaloids may cause lowered blood pressure and nervous system disturbance, as well as the cell damage that they are reported to produce.

Running myrtle poisoning is caused by the consumption of the Catharanthus roseus plant, which is more commonly known as the running myrtle or periwinkle. This dangerous beauty has more than a hundred different toxic properties including dimeric alkaloids, vinca alkaloids, and indole alkaloids. These substances prevent cells (blood cells, protein) from dividing as they should. The side effects range from minor headache to major cell damage which may be fatal.

If your pet has consumed part of a running myrtle plant, it is best to see a veterinary professional as soon as possible. If you cannot get an appointment with your regular veterinarian, take your dog to the closest veterinary clinic or hospital even if you have not seen any symptoms yet.

• Bloating
• Abdominal pain
• Vomiting
• Diarrhea
• Fever
• Agitation
• Incoordination
• Depression
• Tremors
• Hypotension (drop in blood pressure)
• Seizures
• Cardiac arrest (heart attack)
• Coma
• Death (rare)

 Types

The botanical name of running myrtle is Catharanthus roseus (previously Vinca rosea), which is from the Apocynaceae family. Some of the additional common names that running myrtle is known by are:

• Baramasi
• Cape periwinkle
• Common periwinkle
• Greater periwinkle
• Madagascar periwinkle
• Old maid
• Rosy periwinkle
• Sadabahar
• Sadaphuli
• Sadapushpi
• Vinca

The running myrtle has over 100 alkaloids that are poisonous to dogs. In fact, many of these are used as cancer drugs, and the vinca alkaloids are the second most commonly used class of cancer drugs in the United States and Europe.

• Dimeric alkaloids (vinflunine, vinorelbine, vinpocetine) cause destruction of certain protein cells
• Indole alkaloids (catharanthine, yohimbine, vincamine, vindoline) are vasodilators that increase the blood flow to the brain and decrease leukopenia (white blood cells), lowering the ability to fight infection
• Vinca Alkaloids (vinblastine, vincristine, vindesine,) destroys certain cells in the body, including tubulin, which is a protein

It is important to bring a part of the plant or a picture if you can, to help the veterinarian identify the cause of toxicity. You should be prepared to describe the incident, including how much of the plant you think your dog consumed and if you have noticed any symptoms. Also, let the veterinarian know if you have given your pet any medicine in recent days or weeks, no matter whether they are prescription or over the counter drugs.

The first thing the veterinarian will need to do is a physical examination, which most often includes weight, height, pupil reaction time, pulse, reflexes, respiration rate, breath sounds, body temperature, blood pressure, and pulse ox (oxygen level). In addition, the veterinarian will probably want to check your dog’s heart muscle and electrical activity with an electrocardiogram (EKG) and may also do an echocardiogram (ECHO). An endoscope will likely be used to check the throat and upper airway for swelling or plant particles that may need to be removed. This will be done while your dog is sedated for safety reasons.

Laboratory tests necessary for diagnosis may include a urinalysis, chemical profile, complete blood count (CBC), blood urea nitrogen (BUN), packed cell volume (PCV), glucose level, and liver enzyme panel. The blood count will show anemia (decreased hemoglobin) and a decrease in the number of white blood cells in the case of running myrtle poisoning. In addition, abdominal radiographs (x-rays) will be needed to check for inflammation and obstructions. Sometimes, the veterinarian may want to perform an ultrasound, MRI, or CT scan as well.

Treating running myrtle poisoning is similar to other poisonings, but will be adjusted depending on your dog’s symptoms and test results. The most common treatment includes evacuation, decontamination, medication, and observation.

Evacuation

The veterinarian will probably give your pet an emetic such as peroxide or ipecac to induce vomiting. Also, activated charcoal will be given by mouth to absorb the toxins still in your dog’s system.

Decontamination

To flush your dog’s kidneys, intravenous (IV) fluids and electrolytes will be given. This will also help prevent dehydration caused by vomiting and diarrhea.

Medications

There is no known antidote for running myrtle poisoning, but there are several treatments that have been effective in some cases. Some of these are pyridoxine, folinic acid, vitamin B12, and thiamine.

Observation

Your pet will probably be kept overnight for observation. While hospitalized, treatment such as fluids, oxygen, and other medication will be given as needed.

Your dog’s chances of recovery are good in most cases. If you do not obtain treatment or in the event that your pet eats a large amount of running myrtle, prognosis will be guarded. Therapy in the hospital should be enough to prevent any lasting complications; be certain to follow all instructions regarding medications and supplements per the veterinary team’s instructions.