Your doctor, nurse practitioner, physicians assistant or veterinarian can prescribe or just give it to you. But it's unlikely that they'd do that, unless they know you very well, know you have had training and experience, and trust you.
Our vet knows my wife is a nurse practitioner, ran the ICU and the ER at a level 1 trauma center, I'm an (ex) paramedic, and we both ran an ambulance service for many years. They send us home with IV supplies, injectable meds, etc. for our pets all the time (this same vet has taken care of our pets for many decades and obviously we know each other well).
It sounds like you are one of the better preppers we have here on ETS. I'd recommend that you take an EMT class and get certified. Become friends with your physician adviser (most likely this person will be an ER physician). Do some volunteer EMT work in the ER, or better yet paid work if they have it. Your knowledge will increase exponentially and so will your personal contacts for things like, "Hey, can I have a bag of NS, a drip set, and an 18ga?"
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