I am no expert, but Two thoughts:
1. I did have a psychiatrist do the “You must stay on this medication for the 2 weeks and until you have done that, I will not give you anything else to try” – but I was around 17, it was depression medication (an ssri), and I had terrible side effects that made me stop at one week. She said roughly the above after I told her why I stopped taking it after 7 days. (I did get help later on from a different doctor who let me try something different, and that was wonderful)
2. My boyfriend of 7 years has severe anxiety, also depression, ADHD, and I strongly suspect PTSD from his past. I have heard of beta-blockers from going to his appointments with him- his psychiatrist mentioned it as something that is sometimes used, but I gather it wasn’t high on her list and she would pair it with something else- if I remember right- like, it would help..but possibly not a lot. Otherwise, from his current and past lists of medication- I don’t know that he has ever tried beta blockers (from childhood to now). But he has been on some strong sedatives in the past (alprazolam, clonazepam- benzodiazepines they’re called) which were more for the worst panic attacks. He’s off both of those now though, and better for it we think.
I’m wary of this doctor- just because of my doctor in the past. I didn’t get proper treatment for about 4-5 more years after that doctor. I was afraid I would go through the same thing again. But I gather now, most people think that doctor was unreasonable. So, keep that in mind. You ARE supposed to try a lot of these for 2 weeks to really get the full effects, just- in my case, I had feelings like bugs under my skin every day by the second day onward. So- I’d say- if it’s reasonable, listen to your doctor. If your doctor gets out of line though, find a new doctor.