Taking Lithium: What You Should Know
For educational purposes only. This post is not medical advice and is not intended to guide your treatment. Please speak with your medical provider about your own care.
If you've just been prescribed lithium — or you've been on it for years and never got a full explanation — this is the practical version. What it does, what to watch for, and the handful of things that genuinely matter.
Lithium has been used in psychiatry for about seventy-five years, and it's still first-line treatment for bipolar disorder worldwide. It works well. It also asks more of you than most medications, mostly in the form of blood tests and paying attention to your body. Knowing why makes the whole thing much easier to live with.
What lithium is doing
Lithium is a mood stabilizer. Its main job is prevention: reducing how often mood episodes happen and how severe they are when they do. It helps protect against both highs (mania) and lows (depression), which is unusual — many medications are better at one than the other.
Two things worth understanding up front:
It's a long game. Lithium isn't like a painkiller where you feel it working within an hour. Its benefit shows up over months and years, in episodes that don't happen. That can make it easy to think it isn't doing anything. Usually that's the medication working, not failing.
It works better the longer you stay steady on it. Consistency matters more than perfection.
Blood tests: why so many
Lithium has what's called a narrow therapeutic window. The amount that helps and the amount that causes problems aren't far apart. Blood tests are how your team keeps you in the helpful range — they're not a sign that anything is wrong.
You'll typically have:
Lithium levels — more often when you're starting or changing doses, then every few months once you're stable. Most people are maintained around 0.6 to 0.8 mEq/L, though your target may differ.
Kidney function — lithium is cleared by the kidneys, so they're checked regularly.
Thyroid function — lithium can slow the thyroid down. This is common and very treatable.
Calcium — lithium can raise calcium levels in some people.
One practical tip that trips up a lot of people: lithium levels are meant to be drawn about 12 hours after your last dose. If you take lithium at night and have a morning blood draw, don't take a dose before the test. Ask your team exactly how they want you to time it, because a mistimed draw can produce a number that leads to a dose change you didn't need.
Fluids and salt matter more than you'd expect
Your kidneys handle lithium a lot like they handle sodium. When your body is low on fluid or salt, it holds onto lithium — and your level can climb even though you haven't changed your dose at all.
This is the single most common way people get into trouble, and the causes are all ordinary:
A stomach bug with vomiting or diarrhea
A fever, or a bad illness with poor fluid intake
Very hot weather, or heavy sweating from exercise or a sauna
Starting a low-sodium diet
Crash dieting or skipping fluids
Keep your fluid intake reasonably steady, and keep your salt intake reasonably steady too. You don't need to be precise — you need to avoid sudden changes. If you get sick with vomiting or diarrhea, or you're going to be out in serious heat, that's worth a call to your prescriber.
Caffeine also affects lithium levels, so a large change in coffee or energy drink intake in either direction is worth mentioning.
Medications that interact
Several common medications raise lithium levels. Always check before starting something new — including over-the-counter products.
NSAIDs — ibuprofen (Advil, Motrin), naproxen (Aleve). These are the big one because people take them without thinking. Acetaminophen (Tylenol) is generally the safer alternative, but confirm with your prescriber.
Blood pressure medications — ACE inhibitors (lisinopril and similar), ARBs (losartan and similar), and thiazide diuretics (hydrochlorothiazide).
Some antibiotics and other drugs.
The easiest habit: tell every prescriber and pharmacist you're on lithium, every time. Pharmacists are good at catching these, and it costs you nothing.
Warning signs to take seriously
Some side effects are just annoying. These are different — they can mean your lithium level has gotten too high:
Tremor that gets noticeably coarser or worse
Nausea, vomiting, or diarrhea
Unsteadiness, stumbling, trouble walking straight
Slurred speech
Confusion, unusual drowsiness, or feeling "out of it"
Muscle twitching or jerking
If you have these, contact your prescriber or seek urgent medical care right away. Don't wait to see if it passes. Your team may tell you to hold a dose — follow their instruction rather than deciding on your own.
Lithium toxicity is treatable when it's caught. Left too long, it can cause lasting neurological damage. This is rare, and it's rare specifically because people act on these symptoms.
The common side effects
Most people on lithium deal with some of these:
Hand tremor — usually fine and often improves. Dose timing changes and cutting back caffeine sometimes help; ask your prescriber before changing anything.
Thirst and frequent urination — very common, and often the most irritating part.
Weight change — happens for some people. Worth raising with your team rather than managing alone.
Upset stomach — often better when taken with food, or with a different formulation.
Feeling mentally dulled or flat — this one gets under-reported, and it shouldn't be. It's a real effect, it's a common reason people quietly stop taking lithium, and there are sometimes adjustments that help. Tell your prescriber.
Acne or psoriasis flares
Many of these improve over the first weeks. If something isn't improving, say so — there are often options. Silently stopping is the outcome everyone wants to avoid.
If you're thinking about pregnancy
Lithium during the first trimester carries an increased risk of heart defects in the baby, and the risk goes up with higher doses. Untreated bipolar disorder during pregnancy and after delivery carries real risks too, including a high risk of postpartum episodes.
There's no universal right answer here — it depends on your illness history, your dose, and your priorities. What matters is having the conversation before you conceive rather than after, so the decision is planned rather than rushed. If there's any chance of pregnancy, bring it up early.
The most important thing: don't stop suddenly
If you and your prescriber decide to come off lithium, it should be tapered gradually over weeks.
Stopping abruptly substantially increases the risk of a mood episode in the following months — the difference between a fast stop and a slow taper is large. There's also some evidence that stopping abruptly can make lithium work less well if you restart it later.
This matters practically, not just theoretically. Prescriptions lapse. Insurance changes. People run out on vacation. If you're going to be without your medication, call before it happens, not after.
And if you're stopping because of side effects, or because you feel well and wonder whether you still need it — that's a completely reasonable thing to raise. Just raise it, rather than acting on it alone.
Questions worth asking your prescriber
What's my target lithium level, and what was my last result?
How should I time my dose before a blood draw?
When am I due for kidney, thyroid, and calcium testing?
What should I do if I get sick with vomiting or diarrhea?
What's the plan if I miss a dose?
Which pain relievers are safe for me?
Disclaimer: This article is provided for educational and informational purposes only. It is not intended as medical advice, diagnosis, or treatment, and should not be used as a substitute for consultation with a qualified healthcare professional. Lithium requires individualized dosing and laboratory monitoring. Do not start, stop, or change the dose of any medication without speaking with your medical provider. If you develop symptoms of lithium toxicity, seek medical care immediately. If you are struggling with your mood or having thoughts of harming yourself, contact your provider or call or text 988 (Suicide & Crisis Lifeline, US) for support.
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