Medications
Lithium Before Surgery
Lithium is an effective mood stabiliser with a narrow safety margin — and surgery, fasting and fluid shifts can tip its level too high. That's why teams plan its timing carefully and check your blood levels, rather than leaving it to chance.
Quick answer
Why it matters
Lithium has a narrow therapeutic window — the gap between a helpful level and a toxic one is small. The kidneys clear lithium, and anything that concentrates it (dehydration from fasting, blood loss, or reduced kidney blood flow during surgery) can push the level up quickly.
Several perioperative medicines make this worse: NSAIDs, ACE inhibitors/ARBs and some diuretics all raise lithium levels, and lithium can also prolong the effect of certain muscle relaxants used in anesthesia.
Because of all this, teams often pause lithium briefly around major surgery, keep you well hydrated, and check levels — then restart it safely once you're eating, drinking and stable.
Do not stop without instruction
What to ask your doctor
- Do I stop my lithium before surgery, and exactly how many hours before?
- Will my lithium level and kidneys be checked before and after?
- How will you keep me hydrated while I'm fasting?
- When do I restart, and should my psychiatrist be involved?
Red flags — call your team
Red flags — call your team
- Coarse tremor, twitching, or muscle weakness
- Nausea, vomiting or diarrhea (these also worsen toxicity by dehydrating you)
- Drowsiness, confusion, slurred speech or unsteadiness — possible lithium toxicity, seek urgent care
References
- Reflects standard perioperative guidance for narrow-therapeutic-index drugs; exact timing varies with the surgery, your kidney function and lithium level. Coordinate with your psychiatrist and surgical team.
Frequently asked questions
Why is lithium stopped before surgery?
Because lithium has a narrow safety margin and surgery can concentrate it. Fasting, dehydration, blood loss and reduced kidney blood flow can all push lithium toward toxic levels, so for major surgery it's often paused for a day or two and your levels are checked — then restarted once you're stable and hydrated.
Is it safe to stop lithium for a few days?
A short, planned pause around surgery is generally managed safely when your psychiatrist and surgical team coordinate it, with a clear restart plan. What's risky is stopping it abruptly or for too long on your own, which can trigger a relapse. Always involve your prescriber.
What are the signs of lithium toxicity to watch for?
Early signs include a coarse tremor, nausea, vomiting or diarrhea, and feeling unsteady; more serious signs are drowsiness, confusion and slurred speech. Vomiting and diarrhea are doubly important because they dehydrate you and raise the level further. Seek urgent medical help if these appear.
When do I restart lithium after surgery?
Usually once you're drinking and eating normally, your kidneys are working well and your level has been checked — your team and psychiatrist will set the exact time. Don't restart on your own without that go-ahead, as the right dose may need confirming.