Dosing Tips: Lithium for Bipolar Disorder

PSYCHPEARLS POSCAST

In a recent podcast, the presenters listed 4 mood stabilizers that stand out in bipolar disorder treatment. In this podcast, Dr Aiken and Ms Newsome will discuss how to dose one of them: lithium.

Transcript (edited for clarity).

Kellie Newsome, PMH-NP: Dr Aiken, how do you start a patient on lithium?

Chris Aiken, MD: I start patients on lithium very slowly. This is a medication that is meant to work for the long term. It is not that effective for acute episodes, so there's no reason to rush it. Patients are often afraid of lithium; it has kind of a bad reputation out there, which isn't necessary because it's relatively well tolerated. For example, it has a chance of causing sedation around 1 in 28 patients, compared with 1 in 5 or 1 in 10 for most other mood stabilizers. It is also a little friendlier when it comes to weight gain and cognitive side effects than many of the other mood stabilizers.

If you start lithium too quickly, the patient is liable to stop it because of one big side effect: nausea. That is the one you need to prepare them for. Nausea shouldn't be a reason to stop lithium, because it almost always gets better with time. So if you can just get your patient through that whether it's using ondansetron or ginger tablets or taking it after food or raising the dose real slowly, it'll pay off in the long term.

Generally, I'll start with 300 mg at night and raise it by 300 mg each week until I reach 900 mg, at which point, I'll check the level. If the patient is on a drug that interacts with lithium, such as hydrochlorothiazide, or if they're older or frail or afraid of side effects, I'll start lower cutting all of those doses in half. Of course, if your patient is actively manic or you're trying to keep them out of the hospital, you might go faster with this.

Kellie Newsome, PMH-NP: Do you give lithium all at night or twice a day.

Chris Aiken, MD: Lithium is often dosed twice a day, but I think that's out of convention rather than science. Its half-life is 24 hours so there's no reason to do that. And in a few long term studies, patients actually had lower rates of renal problems if the lithium was dosed entirely at night rather than twice a day. It seems that the kidneys do better when they get a bolus of lithium at night, rather than spread evenly throughout the day.

Kellie Newsome, PMH-NP: So what if you're using a high dose? Wouldn't you need to spread that out?

Chris Aiken, MD: First of all, the dose doesn't really matter in lithium; it's the blood level. So that is a good question though, what if the blood level is high, would we need to spread that out. Nobody knows the answer to that. But what I do is if the blood level is going above 0.8, I will spread it out and give a little bit of the dose in the morning. The reason is that we do have long term studies where if lithium level is kept at 0.8 or below, there is much lower risk of renal problems. So we don't know for sure, but I'm hedging my bets and saying let's try to keep that level, less than 0.8 throughout the day to save the kidneys.

Kellie Newsome, PMH-NP: Lithium comes in several forms, instant release, lithobid, and eskalith. Which one do you prefer?

Chris Aiken, MD: Generally, I'll use lithobid, but each has its advantage. Lithobid and eskalith are the extended released versions, and they're going to cut most of the side effects in half so they're better tolerated overall. However, if the patient has constipation, that often improves with the instant release, whereas diarrhea and nausea tend to improve with the controlled release. Another reason you might use the instant release is if you're starting real low like 150 mg, that dose only comes as an instant release, and eskoleth. I can't see much reason to prefer eskoleth over lithobid, other than the tablet size, which does matter to patients. Most patients, rather take 2 pills than 3. And since eskoleth comes as a 450 often use 2 of those rather than 3 of the lithobids, once they get to the dose of 900.

Kellie Newsome, PMH-NP: Once you get to 900 and you check the level, what levels are you actually looking for?

Chris Aiken, MD: This is something we have a lot of research on so there are good numbers to know here. The target level for lithium is 0.6, to 0.8 for depression as well as for the maintenance phase. You want to keep it in that sweet spot. If the patient has active mania, you should go up to 0.8 to 1.2. But you might want to bring it down after they've recovered, again to save the kidneys. Children by the way require the same levels as adults, but if the patient is over 65, they might need levels that are 20% to 30% lower than the ones I just quoted for an interesting reason. In older age, the brain tends to absorb more of the lithium, so they actually get a good therapeutic effect at a slightly lower dose.

Chris Aiken, MD, is the Mood Disorders Section Editor for Psychiatric Times, the Editor in Chief of The Carlat Psychiatry Report,and the Director of the Mood Treatment Center. His written several books on mood disorders, most recently The Depression and Bipolar Workbook. He can be heard in the weekly Carlat Psychiatry Podcastwith his co-host Kellie Newsome, PMH-NP. The author does not accept honoraria from pharmaceutical companies but receives royalties from PESI for The Depression and Bipolar Workbookand from W.W. Norton & Co. for Bipolar, Not So Much.

Kellie L. Newsome, PMH-NP,is the cohost of the Carlat Psychiatry Podcast and is also a practicing Psychiatric Mental Health Nurse Practitioner in Winston Salem, NC, at the Mood Treatment Center. Raised in Tasmania, Australia, Kellie moved to the United States in 1998.

For more on this topic, see Top Mood Stabilizers for Bipolar Disorder.