Aloha! You're speaking to Dr. Michael Salkin
I'm sorry that your question wasn't answered in a timely manner. Here's what you need to know about bromethalin...
Bromethalin uncouples oxidative phosphorylation, decreasing ATP synthesis and causing cell death
. Neurons (nerve tissue) due to their high energy requirements are especially sensitive. This occurs over time and often signs take 24 hours to show up. If you see muscle
tremors, hyperexcitation, or seizures
within hours after exposure, Chance is likely in trouble. However, a more insidious sign, hind limb paresis (weakness) can set in up to 5 days or more later. This may be progressive (fatal), permanent, or gradually improve. The LD50 - the dose at which 50% of dogs die - is about 4.7 mg/kg but 0.75 mg/kg can cause severe signs. Any major ingestion approaching 0.5 mg/kg should trigger decontamination with charcoal. Any dose suspected to be in the 0.5 to 0.75 mg/kg range should be treated with 3 doses of charcoal over 24 hours. Doses greater than 0.75 mg/kg must be treated with 6 doses of charcoal given every 8 hours to reduce enterohepatic circulation. Vitamin K is not the antidote to bromethalin. Once clinical signs appear, treatment remains supportive in nature with mannitol given at 1 mg/kg IV as needed, diazepam for seizures, and anesthesia as necessary. The rodenticide is usually made up of 0.01% bromethalin which equates to 2.84 mg/oz of product. Individual bags are often 0.75 mg but with the new rules, they shouldn't be sold in this kind of single-dose pelleted bags.
It doesn't sound as if Chance ingested enough bromethalin to be a concern. Please respond with additional information and further questions or concerns if you wish.