Lithium toxicity symptoms can start with nausea, vomiting, diarrhoea, weakness or a worsening tremor. Dehydration and some medicines can raise lithium levels, sometimes without a change in your lithium dose. If you take lithium, contact a health professional promptly about significant illness, a new medicine or concerning symptoms; severe confusion, trouble walking or a seizure needs emergency care.
Why Dehydration Can Raise Lithium Levels
Your kidneys clear lithium from your body. When you lose fluid or your body’s salt-and-water balance changes, lithium levels can rise. Vomiting, diarrhoea, fever, heavy sweating and an illness that leaves you unable to drink normally can all create a reason to seek advice. Risk may also change around surgery or other acute illness.
That does not mean you should try to prevent toxicity by drinking as much as possible or changing your salt intake. Aim to keep your usual fluid and salt intake steady, and ask your prescriber what to do if illness disrupts it. There is no single fluid target that is right for everyone taking lithium.
Medicines That Can Interact With Lithium
Some medicines affect kidney function or how the body handles lithium. Non-steroidal anti-inflammatory drugs (NSAIDs), including ibuprofen, can increase lithium levels. The interaction can matter with over-the-counter products as well as prescribed medicines, so check before using an NSAID for pain or fever.
Some blood-pressure medicines can also interact: this includes ACE inhibitors, angiotensin receptor blockers (ARBs) and diuretics, particularly thiazide diuretics. This is not a reason to stop a blood-pressure medicine on your own. A clinician may be able to manage the combination with monitoring or a treatment adjustment.
Tell your prescriber or pharmacist that you take lithium whenever a medicine is started, stopped or changed. Include non-prescription medicines and supplements. Lithium levels may need checking after a change, and the right timing depends on the medicines and your individual treatment plan.
Lithium Toxicity Symptoms To Watch For
Possible early signs include nausea, vomiting, diarrhoea, muscle weakness, blurred vision, unusual drowsiness or a tremor that becomes coarser or worse. More serious warning signs include slurred speech, unsteady walking or poor balance, confusion and seizures.
Some symptoms, such as nausea or a fine tremor, can also occur as lithium side effects without toxicity. Symptoms alone cannot confirm the cause, and toxicity can occur at lithium levels close to the intended range. If you develop new or worsening symptoms, especially during illness or after a medicine change, seek prompt medical assessment rather than trying to judge the lithium level by how you feel.
When To Get Urgent Help
Seek emergency care for a seizure, marked confusion, difficulty staying awake, slurred speech or trouble walking. If you have vomiting or diarrhoea, cannot keep fluids down, or notice worsening tremor, weakness or blurred vision, contact your prescriber, an urgent medical service or a pharmacist promptly for advice. If you may have taken an extra dose, contact your local poison information service or urgent medical service.
A clinician can assess your symptoms and may arrange a blood lithium level and tests of kidney function and electrolytes. The result needs to be interpreted in context, including when you last took lithium and whether you have been unwell. Do not adjust, skip or stop lithium—or change another prescribed medicine—without professional instructions. If symptoms are severe, get emergency help first.
Plan Ahead With Your Care Team
Keep an up-to-date list of your medicines and make sure every clinician and pharmacist knows you take lithium. Ask in advance whom to contact if you develop a fever, vomiting or diarrhoea, or need a new painkiller or blood-pressure treatment. Routine blood monitoring matters, but sudden illness or a medication change may call for additional checks.
