Is Oleander Poisonous to Cats And Dogs?

Common oleander, rosebay, nerium oleander, white oleander — all common names for the oleander plant, an outdoor shrub that belongs to the dogbane family (Apocynaceae) and is popular for its evergreen qualities, delicate pink flowers, and tolerance of poor soil conditions and drought.

white oleander in bloom, green leaves
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Found growing wild alongside highways in warm climes such as Texas, Arizona, Nevada, California, and Hawaii and specifically selected for ornamental gardens, it is deceptively pretty, its milky juice being highly toxic to not only cats and dogs, but also horses, cattle, goats, sheep, camelids, budgerigars, rabbits, horses, and people, too.

Containing naturally occurring poisons collectively known as cardiac glycoside toxins, oleanders affect the heart, inhibiting the sodium/potassium ATPase pump causing a life-threatening high potassium level and also increased intracellular calcium leading to early depolarization, cardiac irritability, and arrhythmias. Its poison also directly interferes with the electrolyte balance within the heart muscle. As well, contact with the plant may cause skin irritation.

Oleander, therefore, should be omitted from your garden if you're a pet parent. And if your cat or dog has eaten any part of the oleander plant, seek professional advice and veterinary care immediately since oleander poisoning can, in some cases, be fatal.

How to identify oleander

Native to the Mediterranean, the oleander is characterized by its tall, shrubby appearance and thick, lance-shaped leaves. Its delicate flowers are rose-colored, and rarely, white or yellow. Long cultivated in greenhouses, a number of new varieties have been introduced over the years; among them is sweet oleander, which is smaller than common oleander, bearing vanilla-scented flowers. However, you should note that all oleanders are poisonous, from their lovely, rose-like flowers to stem, anthers, stigma, seed pods, and root.

Colourful garden on a summer house in Skopelos Island, Greece.
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What makes oleander toxic

Oleander contains toxins that are similar to digoxin or digitalis, a common heart medication used in both human and veterinary medicines. And every part of the oleander plant is toxic; even the water in a vase of fresh-cut oleanders is poisonous. The level of poisoning experienced by a dog or cat depends upon the part of the plant eaten and the amount consumed.

The poisons within oleander that cause toxicosis in pets are cardenolides or bufadienolides. Cardenolides are naturally occurring cardiac glycosides found in plant species throughout the world_._ Some of the butterflies that feed on the plants are poisonous, as well; for example, the monarch butterfly whose larvae feeds exclusively on milkweed (another plant containing cardenolides) renders the monarch poisonous to potential predators.

To further illustrate the extreme toxicity of oleander, Science Direct states that cardenolides isolated from common plants have been used in insecticides and rodenticides for centuries, and fatality in humans occurs after ingestion of only one leaf by children and in adults after eating eight to 10 seeds, 15 to 20 grams of the root, or five to 15 leaves.

Other plants containing glycosides

For your reference, here are a few other common plants that share toxic glycosides. This is by no means a comprehensive list, and to view more, visit the cardenolides page at Science Direct. These plants should be avoided if you are a pet parent or planted in an area where they are completely inaccessible to pets, young children, and wildlife:

  • Dogbane
  • Giant milkweed
  • Foxglove
  • Kalanchoe
  • Lily of the valley
  • Milkweed
  • Star of Bethlehem

Symptoms of oleander poisoning

If you suspect your dog or cat has ingested oleander, you may observe some of the following clinical signs. First among them may be gastrointestinal effects, which will alert you to act fast and seek veterinary care. Further clinical symptoms determined through veterinary diagnostics will confirm oleander toxicosis.

  • Drooling

  • Nausea

  • Vomiting

  • Abnormal heart rhythm or serious dysrhythmias, including second- or third-degree heart block.

  • Abnormal heart rate; bradycardia (too slow of a heart rate) or tachycardia (heart beats more than 100 times per minute).

  • Cardiac arrest.

  • Electrolyte abnormalities; for example, a life-threatening high potassium level

    known as hyperkalemia.

  • Low blood pressure, known as hypotension

  • High blood pressure, known as hypertension

  • Tremors

  • Seizures

  • Dehydration

  • Shock

  • Muscle incoordination, known as ataxia.

  • Abnormally low blood sugar, known as hypoglycemia.

Oleander
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What should I do if my pet has eaten oleander?

As a pet parent, you know that pet emergencies happen so be prepared by having your vet's number on speed dial. But what if your vet is not available when you need her? You should also have the phone number of the nearest emergency veterinary hospital, the ASPCA's National Animal Poison Control Center 1-888-426-4435, and the Pet Poison Helpline 1-855-764-7661 readily available.

If your dog or cat has ingested oleander, time is of the essence. You need to act quickly and get your pet to the vet as soon as possible.

Treatment of oleander poisoning

Treatment for asymptomatic pets:

If your dog or cat presents at the vet without symptoms yet is post-exposure to oleander three hours or less, your vet will consider inducing vomiting, known as emesis, or administer activated charcoal with repeated doses in the case of large exposures.

Several laboratory tests to obtain baseline electrolytes, glucose, and a biochemistry profile will be conducted. Your pet will be monitored in the hospital for at least 12 hours, and if any signs develop, they may last up to three days. In large exposures to oleander, passage of the plant material will be encouraged during this time.

Treatment for pets showing clinical signs of poisoning:

When a dog or cat is showing obvious signs of poisoning such as vomiting and other gastrointestinal, neurological, and cardiovascular effects — typically arrhythmias with secondary hypotension — your vet needs to quickly evaluate your pet's symptoms and aggressively treat them accordingly.

The following are some of the symptoms and the typical treatment protocol, explains the ASPCA:

  • Vomiting may be managed, if need be, with an antiemetic.

  • I V fluids containing a

    balanced electrolyte solution may be administered to rehydrate your pet and provide cardiovascular support.

  • Bradycardia (slow heart beat) and AV block are treated with atropine, which increases the heart rate.

  • Tachyarrhythmias (fast heart beat) are treated with lidocaine, an anesthetic commonly used to treat ventricular tachycardia.

  • Seizures are generally treated with the anti-anxiety, psychoactive medication benzodiazepines, commonly known as "benzos."

  • Electrolyte abnormalities (hyperkalemia) are treated with sodium bicarbonate or insulin-dextrose therapy.

In serious, life-threatening cases of oleander toxicosis, an expensive antidote known as Digibind, or digoxin-specific Fab fragments — the gold standard for severe digitalis poisoning —may be used, but its cost limits widespread use, says Dr. Karen Becker of Mercola.

Prognosis for pets poisoned by oleander

As is the case for any medical emergency with pets, the sooner your pet receives treatment, the better the outcome.

Park with trees and blooming flowers, flower beds, bright sunny day. landscape design
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Conclusion

Oleander is a beautiful but deadly plant which contains toxins that, when ingested, adversely affect the heart, and can induce tremors, shock, and seizures, and in cases of major poison exposure, can be fatal to your cat or dog. Consequently, as a pet parent, learning about the plant, how to identify it, different names it is known by, and what to do in case your pet eats any part of the plant are vital. Of course, preventing your pet from having access to the oleander is the most logical first step in avoiding a poisoning incident.

But oleander is found in many places; growing wild, planted in public spaces, and may be used as a landscape plant at the homes of friends and family you visit. You can be vigilant and keep your pets on-leash or closely supervise pets off-leash. But, unfortunately, accidents can happen as pet parents know all too well.

Bottom line, if your pet ingests oleander, seek veterinary care/professional advice immediately. You can call the National Animal Poison Control Center 1-888-426-4435, Pet Poison Helpline 1-855-764-7661 , or your local emergency veterinary hospital if your vet is not available when you need him. You should be aware that your dog or cat may not show any signs of poisoning at first, but if you know they have eaten any part of the plant, seek medical help right away ..