A Guide to Rhododendron Poisoning In Dogs

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What is Rhododendron Poisoning?

All parts of the rhododendron plant are toxic for dogs. Symptoms include gastrointestinal upset followed by

Hypersalivation Vomiting Lack of appetite Diarrhea Dizziness Weakness Leg paralysis Signs of impaired vision Abnormally slow heartbeat (bradycardia) Hypotension Shortness of breath (dyspnea) Depression Seizures Coma

Large doses can be fatal. Rhododendrons belong to a large genus of flowering plants that includes both rhododendron bushes and azaleas. Numerous species and hybrid cultivars are grown as ornamental garden flowers, while others are found in the wild.

All of these plants contain grayanotoxins (formerly called andromedotoxin) in varying levels. These diterpenoid compounds can disrupt metabolism at a cellular level and interfere with the normal function of nerves and muscles, particularly the heart. They are toxic to dogs as well as humans. The leaves are the most poisonous part of the rhododendron plant, but the flowers and nectar can also be dangerous.

 

Veterinary treatment can ameliorate the symptoms and increase the dog’s chances of survival. Symptoms of Rhododendron Poisoning in Dogs Look for these symptoms if your dog eats rhododendron.

  1. Hypersalivation
  2. Vomiting
  3. Lack of appetite
  4. Diarrhea Dizziness
  5. Weakness Leg paralysis
  6. Signs of impaired vision
  7. Abnormally slow heartbeat (bradycardia)
  8. Hypotension Shortness of breath
  9. (dyspnea) Depression
  10. Seizures Coma

Types Some species of rhododendron contain higher levels of grayanotoxins than others, however with hybridized garden species it’s safer to assume all varieties could be toxic.

If you take your dog abroad it’s important to recognise that some of the  European species can be more toxic than the British variety’s

  • Rhododendron ponticum grows in Turkey around the Black Sea, historically associated with poisoning
  • Rhododendron luteum (Yellow Azalea, Honeysuckle Azalea) is native to Eastern Europe but also grown as a garden ornamental and the base of many hybrid cultivars
  • Rhododendron occidentale (Western Azalea) is found in California and Oregon
  • Rhododendron macrophyllum (California Rosebay) plants are found from British Columbia south to central California

Rhododendron albiflorum (Cascade Azalea, White Rhododendron) can be found from British Columbia south throughout the Western United States, as far east as Colorado Kalmia latifolia (Mountain Laurel) is a wild variety found in eastern United States; this plant belongs to the same Ericaceae family as the rhododendron genus

How Dogs Get Poisoned.

Simply dogs eating flowers or leaves from a garden bush with expose them to grayanotoxins and small dogs are more at risk because their small bodies may have trouble eliminating poison

Yes dogs will eat anything, we couldn’t find a picture of a dog eating a Rhododendron so here’s one eating an equally poisonous tomato plant.

Non Commercial Honey

Honey made from rhododendron nectar has been the most significant source of toxicity for humans and dogs dating all the way back to a well-known case of Greek soldiers being poisoned by contaminated honey in 4th century B.C.E. Modern instances associated with non-commercial honey consumption have been documented in Turkey. Poisoning from rhododendron honey is called honey intoxication or mad honey disease; it produces dizziness, weakness, nausea and vomiting with more severe symptoms and death possible at higher doses.

So you’re not feeding honey you bought locally to your dog anyway are you, but you need to know in case you bought some from a home made or local farm, in an area where there’s rhododendron’s, admittedly very rare but we share because we care.

 

What To Do

If you know your dog has eaten leaves or flowers from a rhododendron bush, it’s best to call a veterinarian or a poison helpline here 

Some dogs do regularly consume a small amount of rhododendron leaves without developing symptoms, but this depends a lot on the specific variety of rhododendron as well as the size of your dog. Emergency veterinary treatment is needed immediately if symptoms are severe

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Diagnosis is based on a history of ingestion as well as symptoms. Vomiting and gastrointestinal upset are non-specific signs of toxicity, but combined with an abnormally slow heart rhythm, and atrioventricular block, this could suggest grayanotoxin toxicity.

The veterinarian will physically examine your dog and listen to his heart. Unusual rhythms will be further analysed using an echo-cardiogram or an electrocardiogram.

Blood tests may also show electrolyte abnormalities. If you aren’t sure what happened, other possible causes will need to be eliminated. Treatment of Rhododendron Poisoning in Dogs For initial treatment, remove any un-swallowed plant material from the mouth, and rinse with water or milk. Encourage your dog to drink fluids to dilute the toxin. Don’t induce vomiting unless recommended by a veterinarian or a professional poison expert.

Immediate veterinary treatment is advisable, especially if a large amount was ingested. For recent poisoning, the veterinarian will induce emesis (vomiting). Activated charcoal will be given throughout the first day. This medication will bind to the toxins in your dog’s stomach and reduce further absorption.

Other treatment will focus on the symptoms. Intravenous fluids and additional oxygen may be administered. If bradycardia (slow heart rhythm) is very severe, atropine will likely be prescribed. Quinidine may be given for heart block. If a temporary pacemaker is available for dogs, this can help stabilise the heart until the toxins are excreted. Most symptoms resolve themselves in 24 to 48 hours.

For cases of severe poisoning, your dog will need to stay in a veterinary hospital during that time. Recovery of Rhododendron Poisoning in Dogs Serious rhododendron poisoning is rare since dogs don’t typically eat large amounts of plant material. Most dogs will make a complete recovery, especially with prompt veterinary treatment.

The size of your dog, the amount that was ingested, and the toxicity level in the plant will all be relevant. A veterinarian will be able to better evaluate your dog’s chances upon diagnosis. To manage the condition, try to discourage your dog from chewing on garden bushes and flowers.

If your dog is prone to snacking on green material, try growing grasses that can be consumed safely and interest him in eating these instead of toxic plants. If rhododendron poisoning is a recurrent problem, consider eliminating the bush and plant something else that will be less toxic for your dog, obvious really.

IMPORTANT INFORMATION – please read Find My Lost Dog assumes no liability for the content of the following list. This does not represent a complete list of all poisonous plants and is only intended as a guide. Please contact your veterinary surgeon for advice or treatment immediately if you think your pet has eaten any of the following plants and is showing a bad reaction. Your pet may also have a sensitivity or allergy to a plant that is not on the list, so always be vigilant and seek help if you are worried about your pet’s health.

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1 thought on “A Guide to Rhododendron Poisoning In Dogs”

  1. Thank you for this, another very informative article. I am always trying to spread the word about the many plants poisonous to dogs, so am glad to see this. Please also take a look at Oleander (Nerium Oleander). It”s less common in UK, but is one of the most poisonous on the planet. I bought one from The Range, not realising, and was shocked when I looked it up. Getting rid was a nightmare – as cannot compost, burn, shred or drown!

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