Lithium Interactions: What Medications and Supplements to Avoid

When you take lithium, a mood-stabilizing drug primarily used to treat bipolar disorder. Also known as lithium carbonate, it helps control extreme mood swings—but only if your body can process it correctly. Even small changes in how your kidneys handle lithium can push levels into dangerous territory. That’s why knowing what interacts with lithium isn’t just helpful—it’s life-saving.

Lithium doesn’t just mix poorly with a few random pills. It has clear, well-documented clashes with common medications. NSAIDs, like ibuprofen and naproxen, used for pain and inflammation can reduce how fast your kidneys clear lithium, causing it to build up. A simple headache pill could turn into a medical emergency. Same goes for diuretics, especially water pills like furosemide or hydrochlorothiazide. They lower sodium levels, and since lithium rides along with sodium in your body, less sodium means more lithium stays behind. That’s why people on lithium are often told to avoid salt-free diets or excessive sweating.

It’s not just prescription drugs. ACE inhibitors, used for high blood pressure and heart conditions, also interfere with lithium clearance. Even common antibiotics like metronidazole or trimethoprim can raise lithium levels. And don’t forget supplements—calcium supplements, often taken for bone health, can alter how your body handles lithium, especially if you’re also on thyroid meds. Thyroid function itself is closely tied to lithium, so any change there needs monitoring.

What makes lithium tricky is that you won’t always feel the warning signs. Too much lithium doesn’t always mean nausea or shaking right away. Sometimes it’s just a foggy head, a slight tremor, or more frequent urination. By the time you feel really off, it might be too late. That’s why regular blood tests aren’t optional—they’re part of the treatment plan. Doctors check lithium levels every few months, sometimes more often if you start or stop another drug.

You might be on lithium for years and never have an issue. But one new medication, one change in diet, one bout of the flu that leaves you dehydrated—that’s all it takes. That’s why every pharmacist should know you’re on lithium before they fill any prescription. And you should never start a new supplement or OTC drug without asking. Even something as simple as a salt substitute can be risky.

The posts below cover real cases and practical advice from people who’ve been there. You’ll find guides on how to spot dangerous combinations, what to ask your pharmacist, how to track your meds safely, and what to do if you accidentally mix lithium with something risky. These aren’t theoretical warnings—they’re lived experiences, backed by medical data and pharmacy expertise. Whether you’re on lithium yourself or caring for someone who is, this collection gives you the tools to stay in control, not at risk.