What a scary situation! I am very concerned for your safety and well being. Threats are serious but actually threatening with weapons is a sign that things are escalating quickly. Things may be safer now, but what happens next time? It's very important since physical abuse has been present in the past and seem to be heading in that direction again that you set up a safety plan for yourself and your family. Please check out or resource on Safety First.
https://bpdfamily.com/pdfs/safety_first.pdfAs for the medication, I do not have any experience with these medications. It is possible that perhaps your spouse may respond well to ADHD medication if ADHD is a co-morbid condition. It could also cause things to tip over the edge since it is an amphetamine (basically it's legal speed). In the event that she begins to become paranoid, have delusional thinking, may become hyperactive/aggressive, etc. how are you prepared to respond? You cannot physical stop your spouse from taking this medication, but you can control how you react to her when she does use it. You are in a very tough spot.
Getting people with BPD into counseling and to stick to it is very difficult. The nature of the disorder itself prevents people from sticking with anything for long periods of time and then add the burden of acknowledging weaknesses in counseling. Add a diagnosis of an incurable mental illness into the mix and it's a recipe for rejecting help.
