If you take your cat to the vet because they're generally feeling blah, they'll often give your cat a quick Vitamin B12 shot to help them feel better
Always use a new, sterile syringe to decrease contamination
Can I Take Too Much Vitamin B12
Vomiting, anorexia, headache, irritability, tremors, and palpitations, can be overdose syndromes (33-34)
So, the right answer to how long is bac water good for is never until the vial runs out. The better answer is until the documented opened-vial window ends, or sooner if the container no longer matches label condition. Why appearance changes matter Official labeling says the solution should be clear and the seal intact
You dont have to do this alone