Oleander Poisoning in Dogs

The oleander plant blooms through the summer into the fall season and is found along roadsides in the southern states, as well as the west coast of the United States. This plant can grow to heights over 6 feet tall and withstand dry conditions and wind. Also grown as a decorative plant for summer gardens in other parts of North America, the oleander is highly toxic and pets must be monitored at all times when in proximity of the tree.

Ingestion of any part of the oleander plant can lead to dire consequences for both humans and animals. The roots and stems contain the most toxins. The leaves and flowers are highly toxic as well, as are the seeds, fruit, nectar, and sap. Even standing water that may have had oleander leaves floating in it will have a poisonous component. The record of the death of a horse who ingested between 10 to 20 leaves proves that this plant can be lethal. Documentation states that most cases of poisoning are related to the leaves.

Signs of poisoning will include increased heart rate and diarrhea. Immediate veterinary care is essential to saving the life of canines who ingest the oleander; if you suspect this may have happened, consider it an emergency situation.

The oleander plant, scientifically known as Nerium oleander, can be deadly to humans and animals who ingest any part of the plant. Cardiac glycosides are present in the plant which affect the gastrointestinal, neurologic and cardiovascular systems severely enough that death is possible with even a small consumption of the plant.

Signs of oleander poisoning can be evident within an hour of your pet ingesting the plant. Do not wait for symptoms to appear because aggressive medical therapy is needed in this case. 

• Drooling
• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Drowsiness
• Dilated pupils
• Lack of coordination
• Inability to rise
• Lethargy
• Weakness
• Abnormal heart rate
• Cardiovascular dysrhythmias including fibrillation (quivering of the heart)
• Collapse
• Death

Types

The oleander found in North America is the Nerium oleander, which is the most familiar  of the species seen along roadsides or in gardens. There are many different colors of this member of Apocynaceae family, depending on the variety. The second most common type is the Thevetia peruviana, found in Mexico and Central America.

If you suspect your pet has ingested some of your oleander tree or you witnessed him doing so, you must treat it as an emergency situation and call your veterinarian to let him know you are on the way. An emergency clinic is also a wise option. Even if you believe that your dog may have eaten only a leaf or two, pets can react to a minimal amount of the plant. The toxicity can also depend on your pet’s size and present state of health.

If you are able to provide the time of the event, the approximate amount of ingestion, and the identification of the parts of the plant that were eaten, this will be of great help to the veterinary team. If possible, bring along a part of the plant.

Contingent on the condition of your dog when he arrives at the clinic, the veterinarian will do a physical examination including abdominal palpation, observance of mucus membranes and checking of pulse rate. There is no specific test for oleander poisoning and the tests that can point to this toxicity are not always time sensitive when results are needed in a hurry.

Blood tests can be indicative to the poisoning in that the presence of hyperkalemia  will be seen in the results. Other helpful markers will be glucose, BUN, and creatinine. An electrocardiogram can be done to verify abnormalities within the heart such as dysrhythmias.

Most dogs who ingest the oleander plant will be hospitalized. If your pet is not vomiting already, the veterinarian will induce emesis. Active charcoal will then be given to your dog in an attempt to bind the poison for elimination. More than one administration is often necessary. 

Your dog’s heart will continue to be monitored, and this is sometimes needed for up to 24 hours. Intravenous therapy will be indicated because this method of medical aid can allow the veterinarian to give your dog drugs like antiemetics, gastroprotectants and medications to help improve the condition of the heart. Severely affected canines may need a temporary pacemaker if the heart is not responding to drug therapy.