Maalox and simethicone are the home remedies/immediate first aid for dogs w/bloat. It can give you another few minutes to get to the vet.
My vet spends a lot of time chasing down various meds that are unavailable. Some, like chewable thyroid have been impossible to get for years.
As for people, I know someone with chronic migraines who has had a standing order at the ER for her medication for years. Last time, it took 2 weeks for the MD to find any. IIRC, they are injectable. She also encountered an Indian MD at the ER who was new to the area. He treated her with contempt, implied she was just a drug seeker (she is in her 60’s)and told her to never show up there again. She filed a complaint and he was fired. It was the second ER doc who took the time to tell her the drug was in short supply and went out of his way to procure it.
Ten of them will buy you time and often stop it in its tracks.
Highly recommended by Great Dane breeders due to their bloating tendencies.