You say the prescription reads 0.5 ml dose. If you have a U100 syringe, that would mean you would fill the syringe to the half way point. In other words, you need to inject 1/2 ml.
( also known as 1/2cc. )
Hope this helps.

I can’t say for sure, but maybe you have had a reaction to the bacitracin. Try reading about its side effects. You could also give your Dr. a call.

There is another choice, Quadmix. I do not know what the fourth drug is, but maybe you should ask your health care provider about it.

With such an old vial, I would be concerned about infection.

I use bimix because the pain from trimix was unbearable. I use 28 units and it is good for about an hour, and that is plenty of time for me. I never get a eager, but definitely enough to be effective.
Your results may vary.

Well, I buy it fresh every month. I’m told it is only safe for 28 days when refrigerated.

There are so many threads on this.
Yes. Bimix works. Trimix, for me, caused a terrible ache. Bimix works great, and its ache free. It took a few months to find the right dose. All is well.
Be patient, you will get there.

I can’t explain it . I can only tell you what happened with me. I was eventually successful with bimix. But it took a few months. I started with ten units, and only went up by one unit at a time. When I reached 20 units and still without success, I consulted with another physician, who suggested I i...

Standing.

Your concern is a reasonable one. I had brain surgery several years ago. Wires were implanted in my head. I was required to take 2 gms of amoxicillin prior to any dental work for the next two years. For those who are not aware, dental work can cause organisms in the mouth to enter the blood stream a...