Lithium Toxicity

What is lithium toxicity?

Lithium toxicity (overdose) happens when you have too much of the prescription medication lithium in your body. It causes intestinal symptoms (like vomiting and diarrhea) and neurological symptoms (like confusion and uncontrolled shaking). If you don’t receive treatment for lithium toxicity, it can be fatal.

Lithium is a natural salt that reduces the symptoms of mania. Healthcare providers mainly prescribe it for bipolar disorder. The medication has a narrow range of safety, so it doesn’t take much to have too much lithium in your body.

There are a few ways lithium toxicity can happen:

• Acute (sudden and severe) toxicity: This happens if you ingest too much of a lithium prescription at one time, or if you have too little water in your body suddenly.
• Acute-on-chronic toxicity: This happens when you normally take lithium every day, but you take an extra amount one day, or if you have less water in your body one day.
• Chronic (long-term) toxicity: This happens when you take a lithium prescription every day, but too much lithium builds up in your body over a long period. This can happen easily because many things — like dehydration, kidney health and other medications — affect how your body handles lithium.

Levels of lithium toxicity

Healthcare providers check lithium levels with a blood test. Your provider will evaluate what’s an appropriate level for you.

In general, levels of lithium toxicity include:

• Mild toxicity: 1.5 to 2.5 mmol/L (millimoles per liter).
• Moderate toxicity: 2.5 to 3.5 mmol/L.
• Severe toxicity: Higher than 3.5 mmol/L.

What are the symptoms of lithium toxicity?

The symptoms of lithium toxicity can vary based on the type of toxicity and the severity.

Symptoms of acute and acute-on-chronic lithium toxicity

Early symptoms of acute lithium toxicity include gastrointestinal (GI) problems, like:

• Nausea and vomiting.
• Diarrhea.
• Abdominal pain.
• Bloated stomach.

These symptoms usually develop within one hour of taking excess lithium.

If you have moderate to severe lithium toxicity, you’ll likely get neurological symptoms after the gastrointestinal symptoms. These include:

• Mental status changes that can range from mild confusion to delirium.
• Uncontrolled shaking (tremors).
• Coordination and balance issues (ataxia).
• Muscle twitches (myoclonus).
• Slurred speech (dysarthria).
• Overactive reflex responses (hyperreflexia).
• Uncontrolled eye movements (nystagmus).
• Hyperthermia (severe cases).
• Seizures (severe cases).
• Coma (severe cases).

Get immediate medical help if you take lithium and have these symptoms.

Symptoms of chronic lithium toxicity

People who have chronic lithium toxicity often develop kidney damage. It’s connected with certain kidney diseases that have different symptoms.

Nephrogenic diabetes insipidus happens when your kidneys can’t properly balance bodily fluids. Your body can’t respond properly to a natural hormone called antidiuretic hormone. Its symptoms include:

• Dehydration, including dry mouth, fatigue and dizziness.
• Excessive thirst (polydipsia).
• Large amounts of urine output (polyuria).

Sodium-losing nephritis happens when kidney damage leads to electrolyte imbalances. Symptoms include:

• Muscle cramps or weakness.
• Mental status changes.
• Fatigue.
• Excessive thirst.
• Polyuria.

Nephrotic syndrome happens when your kidneys release an excessive amount of protein (proteinuria) in your pee. Symptoms include:

• High cholesterol (hyperlipidemia).
• Swelling (edema) in your legs and feet.
• Loss of appetite.
• Abdominal pain.
• Foamy pee.

Chronic lithium toxicity can also cause endocrine system issues, including:

• Hypothyroidism.
• Hyperthyroidism.
• Hyperparathyroidism.

Talk to your healthcare provider as soon as possible if you develop any of these symptoms while taking lithium.

Lithium and serotonin syndrome

Lithium can induce serotonin syndrome, especially if you take other medications that affect your serotonin levels. This is another potentially life-threatening condition.

Symptoms of serotonin syndrome (from mild to severe) include:

• Nervousness.
• Nausea and vomiting.
• Diarrhea.
• Dilated pupils.
• Tremor.
• Agitation, restlessness.
• Muscle twitching and muscle rigidity.
• Sweating and shivering.
• Confusion, disorientation or delirium.
• Rapid heart rate.
• High blood pressure.

Get immediate medical help if you have these symptoms.

What causes lithium toxicity?

Lithium toxicity can happen:

• If you take too much lithium (excessive intake).
• If you’re dehydrated or there are fluid shifts in your body.
• If your body can’t process lithium properly and get rid of it as it should (issues with excretion).

Excessive intake of lithium

Intentional or accidental ingestion of excessive amounts of lithium tablets will cause acute or acute-on-chronic toxicity. It could also happen if your healthcare provider increases your dose too much, but this is rare.

Issues with lithium excretion

Several factors can make it difficult for your body to get rid of (excrete) lithium properly. One main way is a lack of sodium (salt) and fluid in your body (dehydration). This causes your kidneys to reabsorb lithium, which increases the concentration of lithium in your blood. A lack of sodium and dehydration could happen due to:

• Vomiting.
• Diarrhea.
• Fever.
• Kidney failure.
• Diuretics.
• Excessive exercise.
• Excessive sweating (hyperhidrosis).
• Not drinking enough water.
• Having a low-sodium diet.
• Congestive heart failure.
• Pregnancy or labor and delivery.
• Thyroid changes (hyperthyroidism).

What are the risk factors for lithium toxicity?

Risk factors for chronic lithium toxicity include:

• Being over 50.
• Thyroid disease.
• Impaired kidney function.
• Diabetes insipidus. Long-term lithium use also increases your risk of lithium-induced nephrogenic diabetes insipidus, which can then lead to lithium toxicity.

Talk to your healthcare provider if you develop any of these conditions while taking lithium.

How is lithium toxicity diagnosed?

To determine the severity of lithium toxicity, it’s very helpful for healthcare providers to know:

• How much lithium you took.
• What time you took it.
• Whether you took other medications or substances with it.
• If the ingestion was intentional or accidental.

To diagnose lithium toxicity, providers order several tests, including:

• Blood tests to measure your lithium levels.
• Blood tests to measure your electrolytes (like sodium and calcium).
• Blood tests to measure your thyroid-stimulating hormone (TSH) levels.
• Urinalysis.
• Kidney function tests (like blood urea nitrogen and creatinine).
• Brain imaging tests (this is rare).

They’ll also monitor certain aspects of your health, like:

• Your heart with an EKG (electrocardiogram).
• How much you’re peeing (urine output).
• Your oxygen levels — likely with a pulse oximeter (pulse ox).

How is lithium toxicity treated?

Treatment for acute and acute-on-chronic lithium toxicity depends on the severity and how soon you get to the emergency room. The main goals are to remove the lithium from your body and to manage your symptoms. Treatment may include:

• Stomach pumping (gastric lavage).
• Whole-bowel irrigation. This involves taking a special solution by mouth or through a tube that goes through your nose and into your stomach. It clears your gastrointestinal system of lithium.
• Activated charcoal (if you took other medications or substances as well).
• Kidney dialysis (hemodialysis).
• IV fluids.
• Various medications to treat symptoms.

You’ll likely receive treatment in an emergency room. If the toxicity is severe, you may need treatment in an intensive care unit (ICU).

Treatment for chronic lithium toxicity

Chronic lithium toxicity often causes kidney damage. Treatment depends on the specific kind of kidney issue. You may need kidney dialysis.

How can I prevent lithium toxicity?

The following precautions can help prevent acute lithium toxicity:

• Take your medications as prescribed: Only take the amount of lithium (and other medications) your healthcare provider has prescribed. Consider using a labeled pill box or writing notes when you take your medications so that you don’t accidentally take a double dose.
• Store your lithium safely: Keep your medication in an area where children and others can’t find or access it.
• Stay hydrated: Be sure to drink water regularly. Dehydration can lead to lithium toxicity. If you develop vomiting, diarrhea or a fever, contact your provider.
• Always share your medication list with providers: If you’re about to start a new medication, be sure to tell your provider that you take lithium (and any other medications). Certain medications can affect how your body processes lithium.
• Tell your providers if there are any new or sudden changes to your health: Examples include pregnancy and endocrine (hormone) changes.

If you’re having thoughts of suicide or thinking of intentionally overdosing on lithium, call the Suicide and Crisis Lifeline at 988. Someone will be available to talk with you 24 hours a day, seven days a week. Or go to your nearest emergency room for psychiatric evaluation.

Healthcare providers recommend regular blood and urine tests to monitor your health if you take lithium long-term. This can help catch chronic lithium toxicity early. The tests and guidelines include:

• Checking blood lithium levels three to five days after starting lithium or adjusting the dose.
• Checking blood lithium levels every three to six months for people on long-term therapy.
• Checking electrolyte, urea and creatinine levels every three to six months.
• Checking calcium and thyroid-stimulating hormone (TSH) levels every six to 12 months.

What is the prognosis of lithium toxicity?

The prognosis (outlook) of lithium toxicity depends on the type and severity and how quickly you get medical help.

People who don’t get neurological symptoms from acute lithium toxicity don’t usually have long-term complications. If you get serious neurological symptoms, they can become permanent. This is why quick treatment is crucial. In severe cases, lithium toxicity can lead to coma, brain damage or even death.

Chronic lithium toxicity can be difficult to diagnose since symptoms may come on slowly. This delay can lead to long-term kidney and neurological problems.

A note from Cleveland Clinic

While lithium is a powerful and effective medication, taking it requires extra care. Lithium toxicity is a potentially fatal complication that can happen due to taking too much of the medication or having dehydration while on it. Talk to your healthcare provider about ways you can reduce your risk of lithium toxicity and signs to look out for. They’re available to help you and keep you healthy.