What is the best sedative for bi polar? can't sleep.i've heard of ambien cr and lunesta (eszopiclone)

There really isn't 1: Best sleep medicine for bipolar disorder. There are many medications that drs use to treat sleep such as zolpidem (ambien or Ambien cr), Eszopiclone (lunesta), Ramelteon (rozerem), zaleplon (sonata), silenor (doxepine), antidpressants ; benzodiazapines. Antidepressants would not be on the top of my list to give with bipolar disorder. Your dr/ psychiatrist can help determine the best med for you.

No best medicine: I am not sure that there is any specific study indicating the absolute best medication for sleep for the collective of patients with bipolar disorder. Among the likely candidates however there are ziprasidone, olanzapine, and quetapine and specifically these medications also have a characterized capacity to treat mood disturbances attributable to bipolar disorder.

It would be best to discuss this with your Psychiatrist. If you are not confident with your Doctor see another for a second opinion. It's good to have a physical exam to rule out illness. Sleep is very important for physical and mental health. You may need a sleep study to determine why you can't sleep. Also consult with a Clinical Psychologist with expertise in multiple types of psychotherapy.