Friday, March 15, 2013

#FurbabyFridays: A Penny For Your Thoughts? NOT!


How many of you have dogs (or even cats!) that eat or try to eat everything they come across? Now how many of you have had pets that have swallowed coins—specifically pennies? If you are of the group who have answered yes to that last question, you know exactly where this blog will be going and you'll probably relive some pretty frightening moments for you and your pet. For those of you who've never experienced that kind of problem, then stick around. We're about to take another ride on the pet toxins train! All Aboard!

Why are pennies toxic?

If all the circulating US coins, only the penny is toxic. Those minted after 1982 have a core made out of zinc which is then copper plated. These coins are 97.5% zinc. Canadian pennies made from 1997 to 2001 are 96% zinc. For some animals, one penny is more than enough to cause kidney, liver, gastrointestinal and hematopoietic issues like severe, life-threatening anemia. Death can result from the anemia or multiple organ failure.

The scariest part is that the toxic dose of zinc isn't known. Just like with grape and raisin toxicity, the amount can vary for each animal. Also we don't know exactly how zinc causes destruction of the red blood cells or how it causes the damage to the kidneys. What we do know is the acidic environment in the stomach dissolved the copper plating of the penny, thereby releasing the zinc rapidly.

What are the clinical signs?

Since more often than not, the ingestion of the pennies is not witnessed, we don't have clear cut documentation as to how long it takes for the first symptoms to occur. Dogs who have made a snack of pennies can exhibit some or all of the following signs and symptoms.
  1. jaundice (icterus)
  2. anorexia
  3. vomiting
  4. anemia
  5. kidney failure


The severe anemia is the worst symptom and is what attacks multiple organs of the body. Once that happens, you can see collapse, seizures, coma and death. How can you tell if your pet is anemic? Take a look at their gums. Flip up the lip and relax your pressure on it so you don't get a false pale look! If they are less than nice and bright pink, it's abnormal and needs to be checked out. If you see pale pink or even white, you pet is anemic and needs to be seen by your veterinarian IMMEDIATELY.



Birds are another family pet that can suffer from zinc (and lead) toxicosis because they too love to chew on everything in their environment. Some cage materials are constructed of hardware cloth which has lead and zinc in the welds. Being the little destructive creatures that they are, within no time the birds can ingest enough of the zinc and/or lead to become quite ill.

How is it diagnosed?

Diagnosis is based on the clinical signs, history of witnessed penny ingestion and radiographic identification of the coins. Sometimes the coins can cause and obstruction and get held up at some point in the stomach or small bowel. Other times they've passed straight through to the colon by the time they are seen on an x-ray. At this point the patients are usually quite ill as the pennies have been in their systems for several hours at this point. Blood work and a urinalysis are needed to determine the extent of the anemia, kidney and liver disfunction or failure. These samples are also needed to determine the zinc levels in the blood plasma and the urine.

Treatment is of course aggressive supportive care to help correct the abnormalities. The most important part of the whole thing is to remove the pennies from the animal. This can be risky if the anemia is severe, but until the source of the zinc is out, further damage will result and maybe become irreversible.  The zinc itself is a potent irritant in the GI tract so medications like sucralfate and metoclopramide are usually part of the protocol as well, along with blood transfusions, intravenous fluids and in a few cases even dialysis if the kidneys are not producing urine (anuria).

Unfortuanately, something as "simple" as ingestion of a few coins could lead to THOUSANDS of dollars in veterinary bills. Most of these patients will recover within 72 hours of removal of the pennies if treated aggressively. If the pennies are in the colon, then multiple warm water enemas will be performed in order to get them to pass quickly. If the coins got held up in the stomach or small intestine, endoscopy or surgery will be done. Of course, follow up x-rays will be done after the procedures to be sure that all of the pennies have been removed. 

How to prevent this?

Besides pennies, zinc can be found in many other products. Here's a partial list, far from complete but at least it's a starting point. If you have any of these items in your home, please lock them up to keep them out of reach of your pets AND your children. Zinc toxicity also affects humans.




  1. diaper rash ointments such as Desitin  
  2. nuts
  3. bolts
  4. staples
  5. board game pieces ( Monopoly anyone?)
  6. zippers
  7. jewelry
  8. certain lozenge brands
  9. some lotions





To summarize, keep small metal objects and zinc containing creams out of reach. Be on the look out for the nuts and bolts on kennels and carriers. Some may contain zinc so it's best to just assume they all do to keep safe. Use caution when using lotions and ointments on your pets. Unless the product has been specifically prescribed by your veterinarian, DO NOT use them until you can clear it with them as safe to use on your fur baby.



Next week we talk about chocolate toxicity. With Easter coming up, you don't want to miss that one!
~Dr Tammy


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