Take lithium for bipolar disorder? You might think your medication is stable - until a cold, a trip to the gym, or a new painkiller throws your levels off track. Lithium isn’t like other mood stabilizers. It’s a tightrope walk between healing and harm. Even small changes in your body or what you take can push you into dangerous territory. The difference between feeling okay and ending up in the hospital can be as simple as taking ibuprofen for a headache or skipping a few glasses of water on a hot day.
Why Lithium Is So Sensitive
Lithium works by balancing brain chemicals, but your body doesn’t hold onto it well. About 95% of it leaves through your kidneys, unchanged. That means anything that affects how your kidneys work - like drugs, dehydration, or even your salt intake - can change how much lithium stays in your blood. The safe range? Just 0.6 to 1.2 mmol/L. Go above that, and you risk toxicity. Go below, and your mood may crash. There’s no room for error.
Older adults, especially those over 65, are at 3.2 times higher risk of lithium toxicity. People with kidney problems, heart failure, or diabetes are also more vulnerable. But even if you’re young and healthy, one wrong move - like popping an NSAID - can flip the switch.
NSAIDs: The Silent Lithium Boosters
Most people reach for NSAIDs like ibuprofen, naproxen, or celecoxib for pain or inflammation. But these common drugs quietly interfere with how your kidneys clear lithium. They block prostaglandins - chemicals that help keep blood flowing to your kidneys. Less blood flow means less lithium gets filtered out. The result? Lithium builds up fast.
Studies show NSAIDs can raise lithium levels by 25% to 60%, depending on the drug. Indomethacin is the worst offender - it can spike levels by up to 60%. Ibuprofen? Around 25-40%. Celecoxib is a bit safer, but still risky - 15-30% increase. And it doesn’t take long. Toxicity can show up within the first week of starting an NSAID, especially if you’re older or already dehydrated.
One tragic case in New Zealand involved a 72-year-old woman on lithium and an ACE inhibitor for blood pressure. She added an NSAID for joint pain. Her lithium levels weren’t checked regularly. Within days, she developed severe toxicity and died. This wasn’t rare. It’s a warning sign that even experienced doctors sometimes miss this interaction.
Diuretics: The Hidden Danger
Diuretics - water pills - are prescribed for high blood pressure, swelling, or heart issues. But not all diuretics are equal when it comes to lithium.
Thiazide diuretics like hydrochlorothiazide are the biggest problem. They cause lithium levels to jump by 25-50% within 7 to 10 days. Why? They make your kidneys reabsorb more sodium - and lithium rides along. It’s like your body thinks lithium is salt and holds onto it tighter.
Loop diuretics like furosemide are less risky, but still dangerous. They can raise lithium by 10-25%. And potassium-sparing diuretics like spironolactone? The data is mixed. Some patients see spikes; others don’t. It’s unpredictable.
Here’s the twist: some diuretics actually lower lithium. Osmotic diuretics like mannitol and carbonic anhydrase inhibitors like acetazolamide make your kidneys flush out more lithium. That’s a different kind of risk - your mood might destabilize because levels drop too low.
And don’t forget herbal diuretics. Many weight-loss teas, supplements, or “natural” detox products contain ingredients like dandelion or green tea extract. They’re marketed as safe - but they can dehydrate you and raise lithium levels just like prescription diuretics. No label says “dangerous with lithium.” That’s why patients get caught off guard.
Dehydration: The Most Overlooked Trigger
You don’t need a drug interaction to get into trouble. Just lose a few pounds of water.
Lithium floats in your blood. If your blood gets thinner - because you’re sweating, vomiting, having diarrhea, or just not drinking enough - lithium gets more concentrated. Even mild dehydration (2-3% loss of body weight) can raise lithium levels by 15-25%. That’s enough to push someone from safe to toxic.
Think about it: a long flight, a hot day at the beach, a stomach bug, or intense exercise without rehydrating - all of these can be dangerous if you’re on lithium. Travelers to hot climates are especially at risk. One patient might feel fine until they get back from vacation and start feeling dizzy, nauseous, or confused. That’s not a virus. That’s lithium toxicity.
And salt matters too. If you suddenly eat less salt - say, switching to a low-sodium diet - your kidneys hold onto more lithium. That can raise levels by 10-20%. On the flip side, eating more salt can lower lithium levels, which might make your mood worse. It’s not about going back to junk food. It’s about keeping your salt intake steady.
What You Must Do to Stay Safe
Don’t panic. But do take action. Here’s what works:
- Avoid NSAIDs if you can. Use acetaminophen (Tylenol) instead for pain. It doesn’t affect lithium. If you must take an NSAID, use the lowest dose for the shortest time possible.
- Never start a diuretic without telling your doctor. If you’re on lithium and need a blood pressure pill, ask for alternatives like calcium channel blockers or ARBs - not thiazides.
- Drink water - consistently. Aim for 8-10 glasses a day. More if you’re active, sick, or in hot weather. Don’t wait until you’re thirsty.
- Keep your salt intake steady. Don’t suddenly cut back or go on a low-sodium diet without checking with your provider.
- Watch for early signs of toxicity. Diarrhea, dizziness, drowsiness, hand tremors, or blurred vision? Call your doctor immediately. Don’t wait.
Monitoring Is Non-Negotiable
Regular blood tests aren’t optional. They’re your lifeline.
If you start an NSAID or diuretic, your lithium level needs to be checked within 5-7 days - and again at 2 weeks. Some guidelines say weekly for the first month. After that, keep testing every 3-6 months, or more often if you’re over 65 or have kidney issues.
Many doctors miss this. One study found that in fatal cases, lithium levels were only checked “sporadically.” Electronic alerts in medical systems exist - but they’re not foolproof. You have to be your own advocate. Ask: “Has my lithium level been checked since I started this new medicine?”
High-risk patients - elderly, those with kidney disease, or on multiple interacting drugs - should work with a kidney specialist or pharmacist who understands lithium. Shared care isn’t a luxury. It’s necessary.
What If You’ve Already Taken an NSAID or Diuretic?
If you’ve taken an NSAID or diuretic while on lithium - even once - don’t panic. But don’t ignore it either.
Check your symptoms. Are you feeling off? More tired than usual? Nauseous? Shaky? Get your lithium level tested ASAP. Don’t wait for your next scheduled appointment.
If you’re planning to start a new medication - even an over-the-counter one - always tell your prescriber you’re on lithium. That includes cold medicines, allergy pills, or supplements. Many contain NSAIDs or hidden diuretics.
And if you’re going on vacation, traveling, or expect to be sick - pack extra water. Bring a note from your doctor. Know the warning signs. Lithium doesn’t care if you’re on a beach or in a hotel room. It only cares about your fluid balance.
Bottom Line: Lithium Needs Respect
Lithium is one of the oldest and most effective treatments for bipolar disorder. But it’s not a simple pill. It’s a delicate balance - affected by your kidneys, your water intake, your salt, your painkillers, and even your travel plans.
Most people stay safe by staying informed. Avoid NSAIDs. Avoid thiazide diuretics. Drink water. Keep salt steady. Get tested. Speak up.
There’s no magic fix. But with awareness and routine checks, you can keep lithium working for you - without letting it turn against you.
Can I take ibuprofen while on lithium?
It’s not recommended. Ibuprofen can raise lithium levels by 25-40%, increasing your risk of toxicity, especially if you’re older or dehydrated. Use acetaminophen (Tylenol) instead for pain relief. If you must take ibuprofen, use the lowest dose for the shortest time and get your lithium level checked within a week.
What diuretics are safe with lithium?
No diuretic is completely safe, but thiazides like hydrochlorothiazide are the most dangerous. Loop diuretics like furosemide carry lower risk but still require monitoring. Potassium-sparing diuretics like spironolactone have unpredictable effects. The safest approach is to avoid diuretics altogether unless absolutely necessary. If you need one, your doctor should choose carefully and monitor your lithium levels weekly for at least two weeks.
How much water should I drink daily on lithium?
Aim for 8-10 glasses (about 2-2.5 liters) of water daily. Increase that if you’re exercising, sweating, sick, or in hot weather. Even mild dehydration - losing just 2-3% of your body weight in water - can raise lithium levels by 15-25%. Don’t wait until you’re thirsty. Drink regularly throughout the day.
Can low salt intake cause lithium toxicity?
Yes. Your kidneys reabsorb lithium along with sodium. If you suddenly eat less salt - like switching to a low-sodium diet - your body holds onto more lithium, raising your blood levels by 10-20%. Keep your salt intake consistent. Don’t cut back unless your doctor advises it, and monitor your lithium levels if you do.
What are the early signs of lithium toxicity?
Early signs include diarrhea (68% of cases), dizziness, drowsiness, hand tremors, and nausea. Later symptoms may include blurred vision, ringing in the ears, muscle weakness, or confusion. If you notice any of these - especially after starting a new medication or becoming dehydrated - contact your doctor immediately. Severe toxicity can lead to seizures or coma.
How often should lithium levels be checked?
If you’re stable, every 3-6 months is typical. But if you start a new medication - especially an NSAID or diuretic - check within 5-7 days and again at 2 weeks. After that, weekly checks for the first month are recommended. Older adults or those with kidney issues need more frequent monitoring. Always get tested after illness, travel, or major changes in diet or fluid intake.
Are herbal supplements safe with lithium?
Many are not. Herbal diuretics - found in weight-loss teas, detox products, or “natural” supplements - can cause dehydration and raise lithium levels just like prescription diuretics. Ingredients like dandelion, green tea, or parsley may seem harmless, but they’re not regulated. Always tell your doctor about any supplement you take, even if it’s labeled “natural.”
Can lithium toxicity cause permanent kidney damage?
Yes. Severe or repeated lithium toxicity can cause lasting kidney damage, especially in older adults or those with pre-existing kidney problems. The damage may not show up right away, but it can reduce kidney function permanently. That’s why prevention - through hydration, avoiding interactions, and regular blood tests - is far safer than waiting for a crisis.