Dehydration and Lithium: Risks, Signs, and How to Stay Safe

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 has a very narrow safety window. Even a small drop in your body’s water levels can cause lithium to build up to toxic amounts. This isn’t theoretical—it’s a real, documented risk that sends people to the ER every year. The problem isn’t the drug itself, but how easily your body loses its balance when you’re dehydrated.

Dehydration, a condition where your body loses more fluids than it takes in. Also known as fluid deficit, it’s not just about feeling thirsty. Sweat, heat, diarrhea, vomiting, or even just drinking too little water over days can do it. And when that happens, your kidneys can’t flush out lithium the way they should. The result? Lithium levels creep up, and you might start feeling dizzy, shaky, nauseous, or confused. These aren’t just side effects—they’re early warning signs of lithium toxicity, a life-threatening condition caused by excessive lithium in the bloodstream. It can lead to seizures, kidney damage, or even coma if not caught fast.

People on lithium are often told to drink plenty of water—but that’s not enough. You also need to avoid things that make you lose fluids. That includes caffeine-heavy drinks, alcohol, and medications like SGLT2 inhibitors, a class of diabetes drugs that increase urine output to lower blood sugar. These drugs, like dapagliflozin and empagliflozin, pull water out of your body. If you’re on both lithium and an SGLT2 inhibitor, your risk of toxicity doubles. That’s why doctors now check kidney function and lithium levels more often when these drugs are combined.

It’s not just about drinking water. You also need to pay attention to your salt intake. Too little sodium can make your kidneys hold onto lithium instead of flushing it out. That’s why sudden low-salt diets or intense workouts without electrolyte replacement can be risky. If you’re sick with the flu, traveling to a hot climate, or starting a new workout routine, talk to your doctor about adjusting your lithium dose—or at least checking your blood levels sooner than usual.

You don’t need to live in fear, but you do need to be aware. Lithium is one of the most effective treatments for bipolar disorder, and millions rely on it. But like any powerful tool, it demands respect. Simple habits—drinking water regularly, avoiding diuretics, watching for early symptoms—can keep you safe. And if you ever feel off, don’t wait. Get your lithium level checked. That one blood test could prevent a hospital stay.

Below, you’ll find real-world guides on how to spot medication dangers before they escalate—from understanding drug interactions to managing side effects when you’re tired, traveling, or juggling multiple prescriptions. These aren’t just articles. They’re tools to help you stay in control.