Lithium Nephrotoxicity: What You Need to Know About Kidney Risks

If you or someone you know takes lithium for mood stabilization, you’ve probably heard it can sometimes hurt the kidneys. That’s called lithium nephrotoxicity. It’s not a mystery—lithium can change how your kidneys filter blood, and over time that can lead to reduced kidney function. The good news is most people never develop serious problems if they stay on the right dose and get regular check‑ups.

How Lithium Affects Your Kidneys

Kidneys work like a sieve, pulling waste out of your blood and sending it out as urine. Lithium is a tiny ion that the kidney can’t get rid of easily, so it hangs around in the tubules where it can cause inflammation and scarring. In the first few months, the changes are usually tiny and don’t cause any symptoms. After years of high levels, you might see a drop in the glomerular filtration rate (GFR), which is the main measure of kidney health.

Two things make the damage more likely: staying on a high dose for a long time, and having other kidney stressors like dehydration, high blood pressure, or a history of kidney stones. That’s why doctors keep a close eye on blood lithium levels and kidney labs.

Spotting the Warning Signs

Early lithium nephrotoxicity often has no obvious clues. That’s why routine blood tests are key. If you start to notice more frequent urination, swelling in the ankles, or a dull ache in the lower back, bring it up with your prescriber right away. Those could be signs the kidneys are struggling.

Lab results that raise red flags include:

• Rising serum creatinine – a direct read‑out of kidney filtration.
• Dropping eGFR – the estimated GFR tells you how well the kidneys are clearing waste.
• High lithium levels – even if you feel fine, a level above the therapeutic range (0.6–1.2 mmol/L) can stress the kidneys.

If any of these creep up, your doctor might adjust the dose, add a water‑intake plan, or in some cases switch you to a different mood‑stabilizer.

Staying ahead of problems is simple: drink enough water (about 2‑3 L a day unless advised otherwise), keep blood pressure in check, and avoid NSAIDs or other medicines that can further load the kidneys.

When you’re on lithium, schedule kidney labs at least twice a year—more often if you’ve been on the drug for many years or if your levels have been high. The labs are quick, cheap, and give you peace of mind.

Bottom line: lithium is an effective treatment, but it needs a partnership between you and your healthcare team. By watching lithium levels, keeping up with regular kidney tests, and listening to your body, you can minimize the risk of nephrotoxicity and stay on the medication safely for the long haul.