Anyone experienced with bipolar disorder?

First things first; have her diagnosed by a professional psychiatrist. Most counties have support groups for family members of bipolar patients. Seek them out.

Thanks.
That appointment has been set.
I'm concerned about medications, side effects, impact on relationship(s)...etc

Take this all in one step at a time. Bi-polar disorder is something that a person faces for an entire lifetime. One of the big problems with the disorder is that a person will take medication, will feel well, go off the medication, and subsequently develop symptoms again. In many families, this cycle repeats over and over again.

Here is reading from a credible source that can get you started:

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001924/

That's the reason you need to have her see a doctor - who can diagnose the problem, and recommend the right kind of meds. The meds may be changed frequently depending on the reaction of the patient, but the patient must continue to take the meds even when they think they're cured, because they are not.

You are right to be concerned. I have a friend who was so diagnosed. By voluntary committment, he was treated with lithium for several weeks. When stabilized, he was released with a supply of the drugs and instructions. Whether they got the dosage wrong, made the wrong diagnosis, or he simply took too much, or too little, he went into a fit of depression like most of us will never know. In fact, he ended up being involuntarily committed after standing off a sheriff's posse at his ranch.

As a matter of fact, I have never been completely convinced of the diagnosis. Certainly, he was considered something of an oddball, but I don't think he was really outside the normal range of behavior.

Not relevant to the question, but the guy was referred from one doctor to another, and the other turned out to be a psychiatrist, a fact he was not aware of at the time. I have been very cynical about that, and related professions ever since.