OTC Drug Toxicity

Over The Counter Drug Toxicity

By Dr. Karen Burgess

There are numerous over the counter pain relievers readily available to people. Often these medications may seem like an affordable and simple thing to try for your dog or cat, but many of these products can be very dangerous even at seemingly safe doses.

Aspirin falls into a category of drugs called non-steroidal antiinflammatories or NSAID for short. There are many NSAIDS available for pets and humans and as a class they are effective pain relievers and blockers of inflammation.

Depending on the chemical makeup of a particular NSAID there can be varying degrees of negative side effects. After ingestion of aspirin, salicylate is the potentially toxic metabolite produced in the body. The most common side effects seen with Aspirin include stomach wall bleeding (ulcers), slower clotting times (tendency to bleed), and kidney damage. While the pain relieving benefits tend to be brief (8 to 12 hours), toxic effects tend to last much longer (7-10 days). In one study it was shown that all dogs given aspirin at an appropriate dose had visible gastric bleeding. While many think that enteric coated or buffered aspirin are a safer option, the coating allows variable absorption and in humans are associated with increased risk of gastrointestinal bleeding. Aspirin is rarely recommended for pain relief in human medicine anymore as there are safer options available. The primary way aspirin is now used for people is at low doses (think baby aspirin for an adult) to “thin blood” or help prevent clot formation.

Unfortunately for the unknowing pet owner, aspirin is readily available in the pet care aisle and even labeled for pet use. Many assume because marketed in this way that this is a safe option when in fact it can be a very dangerous choice. Current acceptable dosing for aspirin is also the dose which can cause stomach ulcers. Additionally, after even one dose of aspirin no other NSAIDs or steroids should be used for 7 days. This means that much needed effective and safe pain relief may not be an option for your veterinarian to prescribe after aspirin use.

For cats aspirin is particularly dangerous. Ingestion of even one aspirin would likely be fatal. The metabolism of aspirin is much slower in cats making a daily dose of baby aspirin extremely dangerous.

Signs of toxicity from aspirin including vomiting (with or without blood), diarrhea, loss of appetite, bloody or black stool, excessive bruising, bone marrow suppression, weakness/depression, or death.

Baby aspirin contains 81 mg aspirin, regular strength 325 mg, and extra strength 500 mg. What many may not realize is that Pepto-Bismol products may contain 262 mg salicylate per TBSP or 300 mg salicylate per tablet. Check all labels carefully before giving a medication to your pet as aspirin is a common add on ingredient in over the counter products.

Ibuprofen is an NSAID that decreases inflammation, reduces fever, and provides pain relief. Toxicity concerns are similar to Aspirin (gastric ulceration, clotting issues). Similar to aspirin, there is a dose recommendation for dogs, but this is typically discouraged due to potential negative side effects. Cats are less tolerant of ibuprofen than dogs.

Acetaminophen provides both pain and fever relief but does not affect inflammation or clotting like NSAIDs. While the safe dose range is narrow, in many dogs acetaminophen products may be a safer option to assist with pain. Cats lack the ability to break down acetaminophen in the liver and even one dose of acetaminophen may be fatal (10 mg/kg). Toxic dose in dogs are typically seen at doses exceeding 100 mg/kg.

Symptoms of toxicity may be more likely to develop in smaller dogs or those with underlying liver disease. Lethargy, swollen face, blue gums, shortness of breath, and yellow tinged skin are all possible signs. Hospitalization and intensive treatment may be necessary with more serious exposure.