Bay Center For Jaw Surgery

I had an emergency tooth extraction & they were kind enough to take me. The dentist removed the tooth, no problem. The assistant and i discussed meds and 2 drugs were agreed, one for infection and one for pain. She told me she phoned in the script, so i could pick the drugs up on my way home.
Imagine my surprise when I got home and saw the drug for infection was change to something I am highly allergic to. I called the next morning and asked someone on the staff to call the pharmacy and prescribe the original drug. I assured it would be done. At noon I called the pharmacy only to discover NOTHING was being processed. I called again and reiterated my request for them to call my pharmacy and prescribe this drug. It was finally done.
My concerns are: 1] why was drug changed without discussion with the patient. 2] If they had at least look at my paperwork, they would have seen where it says: drug allergies, I was highly allergic to the drug they changed to.
As with any medical procedure, the patient should be alert and kept informed. If any pre-​agreed procedure or drug changes, the patient must be immediately told and not changed on the whim of an assistant. NOW I will double check everything and make sure nobody pulls a switcheroo with me in the future.