If this person had borderline PD, I hope you are recommending DBT and only continuing medications if it's justified.
Psychotropic medications don't show much benefit with borderline PD and are not considered first-line treatments for it.
Despite that, several psychiatrists continue the practice of treating borderline PD in a manner that goes against several treatment philosophies.
1) DBT is the treatment of choice yet several psychiatrists, not understanding DBT or having anyone they know who could provide it, do not point borderline PD patients in this direction.
2) Several psychiatrists diagnose borderline PD as having mood disorder NOS, psychosis NOS, etc even though the DSM clearly indicates that a diagnosis of borderline PD or the other disorders are due to symptoms not from another disorder. I've heard psychiatrists argue "This patient is so parasuicidal, it merits a mood disorder NOS diagnosis." Not according to the DSM.
3) We psychiatrists are supposed to avoid polypharmacy when available. When we prescribe psychotropics, we are supposed to do so in a manner where we use the least amount needed and only if the benefits outweigh the risks.
In the treatment of those with borderline PD, giving out medications--to the point where it becomes a stew goes against all the above.
That said, if someone does have borderline PD, don't close off your mind to the possibility that psychotropics may help. Borderline PD is often times comorbid with PTSD. Try to find out if the person has PTSD and treat that disorder. Psychotropics may also help acute breakthrough symptoms. (E.g. an antipsychotic if the person is experiencing a micro-psychotic episode, but strongly consider stopping the antipsychotic when the episode ends). The person may also have a true comorbid condition, though don't diagnose something such as psychosis NOS unless there are reasonable medical grounds to do so. A borderline showing impulsivity and dysregulation of anger is not somehow psychosis NOS despite what some of my teaching attendings told me in residency. It's simply borderline PD.
But do not throw more and more medications at someone with borderline PD and expect it to treat someone as if they had panic disorder and you're giving them an SSRI. It doesn't work that way.
Of the borderline PD patients I treat, if I get to the point where I don't think psychotropics will help, or they are doing as much help as they can, I simply tell the patient that I don't think it's worth it to continue to see medications as the answer and that psychotherapy, if it already hasn't started, has to be the end goal of getting them better.
I pretty much never give any borderline PD patient a substance of potential abuse unless they have a comorbid disorder that truly merits it's use. (e.g. Borderline PD and ADHD--and ouch, yes they are hard to differentiate in the same person). Even then I try medications to treat the ADHD that are not stimulants such as Wellbutrin or Strattera.