What are your symptoms mainly right now and how much does cycling and mania get in the way? I'm going to preface all this with stating everyone reacts to meds a little differently, but there are some general trends, and this is my experience and what I read from others.

Effexor is an antidepressant (like Lexapro) and they're not really supposed to be used for bipolar because of a significant risk of mania and rapid cycling. I took Effexor myself, and it worked really well to get me out of a depression, but then after a couple months I had another depressive episode, so they bumped up the dose and then I immediately went into some crazy mixed cycling stuff (over the five months I was on it, I had to get A LOT of medical treatment from self-harm, self-neglect, and a suicide attempt). It's also one of the hardest antidepressants to come off of for many (my IP doc wanted to put me in an Ativan coma for it).You're on Lexapro (an SSRI), and Effexor is an SNRI. SNRIs are thought to have a higher rate of causing elevated mood than SSRIs for people with bipolar, too. Just something to keep in mind. That being said, a lot of people with bipolar are on antidepressants and get some benefit from them, but it's important to have something that absolutely works for (hypo)mania.

Lithium was my favorite med I've been on. WAS. It worked so well but I wasn't compliant and got a three months supply and long story short my kidneys are wrecked now. It's gold standard for "classic" bipolar (euphoric manias, normal or hyperthymic temperament, longer periods of euthymia, not as many major comorbidities as "atypical" bipolar, later onset, etc.). A lot of docs aren't a huge fan of it though because of the lab monitoring and easy potential for toxicity if, say, you change your water, salt or caffeine intake.

Lamictal in my mind is an antidepressant that's somewhat safe for people with a history of mania. Less of a "mood stabilizer" (though that's what they consider it). When I was on it, my pdoc tried treating some hypomania by increasing the dose, and it didn't help at all. Definitely an underrated drug though if you're either one that it does work for the ups or if you have something else that covers that. Also titrating up is a bytch. A slow bytch.