Are those packaging freshness packets really toxic to dogs?

Plenty of packages for dried food, medications and even shoes contain small packets placed there by the manufacturer to maintain freshness. The purpose of these little packets is to either reduce moisture in the packaging or to absorb oxygen. But canines love to chew them up. Fortunately, most are harmless and require minimal or no veterinary care. Here are the three common ingredients and how they affect canines:

Silica Gel

> Is it toxic? Virtually non-toxic.

> What is it? Silica is a hard, porous, synthetic gel placed in products to control humidity and prevent degradation. Silica gel packets are usually 1 inch by 2 inches and contain multiple small white, clear or opaque beads inside.

> Why is it labeled “do not eat”? The packet carries a “do not eat” label because it’s not intended for consumption. The dust from the processing and creation of silica is irritating to the skin, respiratory tract and gastrointestinal tract. Employees in mines or factories chronically exposed to or inhaling silica can develop a debilitating disease called silicosis. Fortunately, our furry friends rarely encounter silica dust. Some silica products are mixed with a moisture indicator, these indicators may be toxic in large doses. If a dye is present, the silica gel will no longer be clear or white, but instead bright orange, blue, pink or green.

> Is it a threat to dogs? No true toxicity risk exists from exposure to silica gel packets. The beads do not enlarge in the stomach, and the exterior packaging is usually soft and presents little risk of injury of obstruction.

Charcoal or Activated Carbon

> Is it toxic? Virtually non-toxic.

> What is it? A specific type of prepared charcoal (similar to activated charcoal used in veterinary hospitals) is found in white plastic cylinders inside bags of prepared foodstuffs like dog treats, chews and jerky. If the cylinders are broken open, the small black granules are visible. These granules are not magnetic (as compared to iron).

> Why is it labeled “do not eat”? The charcoal carries a “do not eat” label because it’s not intended for consumption.

> Is it a threat to dogs? The cylinder can cause a foreign body obstruction in small dogs and can damage the oral cavity when chewed. However, no true toxicity risk exists from the charcoal or external canister. In case you were hoping to save some money by saving the charcoal in these canisters for use in the clinic, think again. You’d need to administer the contents of thousands of canisters before achieving any therapeutic benefit! Best to stick with good old activated charcoal.

Iron

> Is it toxic? Potentially toxic.

> What is it? Elemental iron granules are placed in small packets called oxygen absorbers and added to bags of prepared or dehydrated food to absorb excess oxygen. This prevents oxidization (rancidity) of the food and preserves freshness.1 Oxygen absorber packets are typically about 1 inch by 1 inch and are often found in packages of beef jerky, pepperoni, dried fruits, dog jerky treats, etc. If the oxygen absorber is broken open, dark brown or rust-colored material is visible. This material is magnetic, which allows for quick differentiation between packets containing iron and those containing silica gel or charcoal.

> Why is it labeled “do not eat”? Elemental iron can cause severe poisoning, even in the small amounts contained in one oxygen absorber packet.2 It also irritates the gastrointestinal tract and has direct corrosive effects. After ingestion, vomiting (with or without blood) is one of the first signs of poisoning. In fact, vomiting is such a common finding that if a dog does not vomit, it’s probable that a toxic dose was not ingested. If the dose is large enough to cause poisoning, severe metabolic acidosis, shock and hepatic toxicity can develop one to five days after the exposure. Pet Poison Helpline’s most severe reports of iron poisoning from oxygen absorbers have occurred in small dogs (less than 15 pounds). Unless a large dog ingested several oxygen absorbers or ingested unusually large ones, poisoning is much less likely.

Case management

Owner history

Most owners will call to report that their dog ingested the packet inside of a container. First, ask how much was ingested and if there is any left. If there is, ask whether the packet is labeled, what color the contents are and whether the contents can be picked up with a magnet. If the packet was ingested whole, ask the owner whether there’s another package in the home to evaluate.

Triage

> If the product is labeled “silica” or if the contents of the package are white or clear beads, the owner can monitor at home and no treatments are needed. If the contents are dark in color, the owner should place a magnet over the black powder, if it isn’t magnetic, the product is likely nontoxic charcoal and, again, the owner can monitor at home. If the owner doesn’t have a magnet, the powder is magnetic or the product was swallowed whole, it should be assumed that iron might have been ingested and further action is needed.

> If the dog weighs less than 15 pounds, the risk for poisoning is increased compared to large dogs.

> If at-home decontamination is appropriate, the pet owner may induce vomiting with hydrogen peroxide and then give one to three teaspoons of aluminum or magnesium hydroxide (Alternagel or Milk of Magnesia) to reduce the systemic absorption of iron. Alternatively, a quick call to Pet Poison Helpline can readily help determine the pet’s risk and need for decontamination. Following emesis, the pet owner should attempt to identify the contents of the packet or bring the pet and the remaining product, the emesis, or a duplicate of the product, if available, to the clinic.

Diagnosis

The first goal is to determine if the ingested material contains iron. If a duplicate is available, there are two characteristics of iron that can help—it’s magnetic and it appears on a radiograph as a metal density. If the entire product was ingested, consider taking a radiograph to look for a metal dense object in the stomach. Exposure can also be confirmed with a serum iron level taken four to six hours after ingestion. This lab test can often be run quickly and inexpensively at a local human hospital.

Treatment

> Depending on the amount of iron ingested and the size of the dog, additional decontamination may be needed. Following the induction of emesis, gastric lavage or whole-bowel irrigation may be necessary. Administration of oral aluminum or magnesium hydroxide (Alternagel or Milk of Magnesia) may prevent some systemic absorption of iron by precipitating elemental iron into an insoluble form. Activated charcoal is not of benefit as it does not readily bind to iron and should not be given.

> The pet should be given supportive care until the serum iron level results are returned to normal (46-214 mcg/dL). If clinical signs of gastrointestinal upset are seen, anti-emetics, H2 blockers such as famotidine, sucralfate and IV fluids may be needed.

> The pet should be given supportive care until the serum iron level results are returned to normal (46-214 mcg/dL). If clinical signs of gastrointestinal upset are seen, anti-emetics, H2 blockers such as famotidine, sucralfate and IV fluids may be needed.

> If the iron level comes back greater then 300 to 400 mcg/dL chelation therapy with deferoxamine may be necessary to prevent organ damage.3

References

1. Byun et al. Oxygen scavenging system containing a natural free radical scavenger and a transition metal, Food Chemistry 124(2011) 615-619.