What about Mirtzapine? I'm presuming there's a concern with certain ADs triggering a manic episode when treating the depressive portion of Bipolar illness, hence the consideration of either an atypical antipsychotic and/or mood stabiliser in preference? I just though of Mirtazapine because it's what my Psychiatrist prescribes me for depressive episodes (no Bipolar Disorder here, but some of the other ADs I've tried have tipped me into a manic state, hence the decision to go with Mirtazapine for reasons that were explained to me but that I can't remember off the top of my head). I don't know how different Bipolar Depression is to Unipolar Depression, but I've always found Mirtazapine to be very effective at mood stabilisation, anxiety reduction and pulling me out of a bad depression fairly promptly. Of course I'm not a Doctor so I could obviously be way, way off with this line of thought.
I won't get into the controversies of using mirtzapine in general because what works for you and your doctors... works!
We are actually learning more and more that bipolar depression really is quite different from unipolar depression in many ways.
So I believe according the the DSM a hypomanic/manic state that was clearly precipitated by a medication, such as an anti-depressant, doesn't meet criteria for diagnosis of bipolar disorder. However, to many psychiatrists it is more complicated than that. For sure, in such a patient, more caution is warranted in whatever centrally acting medications you will prescribe them.
In my experience, I have had more than one psychiatrist either declare that these patients are bipolar just waiting to happen and therefore they call them as such. I've had other also say that while they don't meet criteria, for their purposes they end up *treating* them as though they were bipolar all the same.
In any case, those patients are more of a grey zone and standard treatments for depression can still be used, albeit with a bit more caution.
However, in the patient with a full proven diagnosis of bipolar disorder, especially if being initiated on medication by a non-psychiatrist, they tend to be approached in a more "traditional" way, in that they will be given medications that are FDA approved for bipolar depression and do NOT cause mania.
Typically I see PCPs use Seroquel the most. I believe this is because it is one of the most effective for depression, but also is effective for treating mania (so not likely to cause mania), and it tends to work faster. Faster than medications like lamotrigine which can have an effective overdose suicide potential. Lithium is another one for bipolar depression as well, but with its numerous medication interactions, need for monitoring, serious potential side effects, narrow therapeutic index for toxicity, many non-psychiatrists feel less comfortable starting this themselves.
Traditional antidepressants, in conjunction with a mood stabilizer and a patient that is certainly not in a mixed state, dysphoric mania, or just mania adjacent, can be used in BPAD. They can even, with extreme caution, be used ALONE in SOME cases, but this would be highly unusual and I doubt you would see a PCP this brave. If this happened at all you would likely see it done by a psychiatrist and with close follow up.
Given the sheer number of effective drugs that a PCP likely has more experience with, and with a favorable drug profile, I would not expect them to use mirtazapine. For various reasons, it is falling out of favor greatly.