As we transition into discussions on multiple ingredient toxins such as household cleaners, synthetic versus natural, safe plants, and other Spring/Summer poisons, I want to touch on the topic of toxicity.
The word “toxic” is misleading
There is no substance on the planet that will not make your pet sick if ingested in a high enough quantity, (not even water)! Even the oxygen we breathe does damage to our cells over time, eventually contributing to our death.
What this means is that there is nothing that can be 100% genuinely non-toxic. Anyone that tells you so is either misinformed or trying to sell you something! So, how do we determine toxicity in regards to certain substances?
Overly simplified, there are a couple of terms that can give you an idea of how dangerous a substance may be to your pet:
- LD50 – This is the first term at which you will want to look when trying to determine the safety of any given chemical or substance. It stands for the dose at which 50% of the test population in a lab (usually mice or rats) died (for example, 30 out of 60 of the test subjects died after administration of this dose). You may hear it referred to as a “lethal dose”.
- LD50 can give you a rough indicator of how large a dose it takes to cause death, but keep in mind that it is reported for 50% of the population. The amount that causes death in ONE animal is going to be lower than the LD50. This is called the lowest lethal dose, and is often not publicly available information, since it often takes time to collect enough data to report.
- In medications, LD50 can be found on the informational insert that comes with prescriptions. For other chemicals or over-the-counter medications, companies are required to provide a Safety Data Sheet (SDS) or Material Safety Data Sheet (MSDS). These can be searched on the internet (Google: ibuprofen MSDS), and there you will find the reported LD50.
- Margin of Safety or Therapeutic Index – While this is a more fluid concept based upon how this is evaluated, it can often times be more informative. Mathematically, the margin of safety can be found by dividing the lethal dose by the therapeutic dose (or effective dose) of any substance, or simply by comparing the difference between the two. In medicine, this may also be defined as the difference between the therapeutic dose and a dose known to cause severe signs. The smaller this number becomes, the more dangerous the substance. This is typically not reported as a numerical value, but assigned a designation of narrow or wide.
- A wide margin of safety indicates that it takes more of a chemical to cause death, thus it is safer. A medicine that relieves pain after one pill and severe signs after 60,000 pill would be considered to have a very wide margin of safety.
- A narrow margin of safety indicates that it takes less of a chemical to cause death or severe signs, thus it is more dangerous. A medicine that relieves pain after 1 pill and causes severe signs at 1.5 pills would be considered to have a narrow margin of safety.
- Concentration – This is often most important when considering mixtures of chemicals such as cleaners, home improvement substances, paints, ointments, etc. While a compound medication can often be directly calculated into a dose, this becomes harder with mixed chemicals. Instead, we look at the concentration percent of an ingredient in the formula (this can also be found on the MSDS).
- As an example, looking at bleach versus another household cleaner. Bleach can be up to 100% concentrated sodium hyporchlorite (aka liquid bleach). A cleaner with bleach added to the formula may only have a minuscule amount ( something with 0.005% bleach is not very concentrated). If you put a gallon of bleach into a gallon of water, the water dilutes the bleach, making it 50% concentrated instead.
The above is why animals can swallow paint with anti-freeze in it, but not have the same troubles as they would with concentrated antifreeze in the garage. It is also why alarmists may become concerned after “discovering” that a product contains a certain chemical, but your doctor or vet does not seem to take it seriously. The mere presence of a chemical in a product does not necessarily mean a product is toxic for your pets at home.
If you are concerned about using any product, plant, or medication in your home, speak to your vet or call animal poison control! They are often happy to give precautionary information before an animal is accidentally exposed.Follow Me: and/or
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