Dehydration and Lithium: Risks, Signs, and What You Need to Do

When you take lithium, a mood-stabilizing drug used primarily for bipolar disorder. Also known as lithium carbonate, it works by balancing brain chemicals—but it only takes a small shift in your body’s fluid levels to push it into dangerous territory. Lithium is processed by your kidneys and cleared through urine. If you’re dehydrated, your kidneys hold onto more of it, letting the drug build up to toxic levels. This isn’t theoretical—it’s a well-documented risk that sends people to the ER every year.

Dehydration, a condition where your body loses more fluids than it takes in. Also known as hypovolemia, it can come from simple things: skipping water on a hot day, sweating too much during exercise, or even vomiting from the flu. For someone on lithium, even mild dehydration can trigger symptoms like tremors, confusion, nausea, or muscle weakness. These aren’t just side effects—they’re early warning signs of lithium toxicity, a medical emergency caused by excessive lithium in the bloodstream. The danger is that these symptoms often look like the condition lithium is meant to treat, so they’re easy to miss.

Your kidneys are the key. If you have any kidney issues, take diuretics like hydrochlorothiazide, a common blood pressure pill that increases urine output. or NSAIDs like ibuprofen, your risk goes up even more. These drugs reduce blood flow to the kidneys, making it harder for them to flush lithium out. That’s why doctors check your blood lithium levels regularly—and why you should never change your water intake without talking to your provider. Drinking too little is risky. Drinking way too much isn’t safe either; it can mess with your sodium balance and trigger the same toxic response.

What should you do? Drink water consistently—not just when you’re thirsty. Keep a bottle nearby. Avoid heavy caffeine or alcohol, which pull water out of your body. If you get sick with diarrhea or vomiting, call your doctor immediately. Don’t wait for symptoms to get worse. Lithium toxicity can escalate fast, and early action saves lives.

Below, you’ll find real-world guides on how lithium interacts with other medications, what to watch for when your body’s chemistry shifts, and how to manage your health without guesswork. These aren’t general tips—they’re practical, tested insights from people who’ve been there.