Lithium

Lithium is a mood-stabilizing medication with approved uses across several oral formulations for bipolar disorder.

• Lithium Carbonate capsules and tablets treat acute manic episodes of bipolar disorder and are used as maintenance therapy to reduce the frequency and severity of future manic episodes.
• Lithium Carbonate extended-release tablets (including Lithobid) treat manic episodes of bipolar disorder and provide ongoing maintenance to reduce episode frequency and intensity.
• Lithium oral solution is approved as monotherapy for bipolar I disorder — both for acute manic and mixed episodes and for long-term maintenance — in patients 7 years and older.
• All supported formulations have established safety and effectiveness in patients 7 years of age and older for acute and maintenance treatment of bipolar I disorder; use in children under 7 has not been established.

The exact way lithium stabilizes mood is not fully known. What the science does show is that lithium is completely absorbed in the gut, spreads throughout the body's water (it does not bind to proteins in the blood), and is not broken down by the liver at all. It is cleared entirely by the kidneys, which is why kidney health is so central to using this drug safely. Because lithium distributes into brain tissue slowly — sometimes taking up to 24 hours — effects on mood and the onset of toxicity symptoms may both be delayed.

Lithium is taken by mouth, available as immediate-release capsules and tablets, extended-release tablets, and an oral solution. Immediate-release forms reach peak blood levels within about 15 minutes to 3 hours of a dose; extended-release forms take 2 to 6 hours to peak, which makes the rise and fall in blood levels more gradual.

• Dosing frequency depends on the specific form prescribed — follow your prescriber's exact schedule.
• Blood lithium levels must be checked regularly, usually drawn 12 hours after the last dose, until levels are stable and then on an ongoing basis.
• Dose adjustments are typically made based on blood level results, kidney function, and how you respond to treatment — never adjust the dose on your own.
• If you miss a dose, ask your pharmacist or prescriber what to do — do not double up.

Lithium causes a range of side effects, some common and manageable, others that require prompt medical attention.

• Fine hand tremor — very common, especially when starting treatment
• Increased urination and thirst (polyuria and polydipsia)
• Nausea, vomiting, or diarrhea
• Fatigue or general discomfort
• Dizziness
• Decreased appetite
• Rash or skin irritation
• Blurry vision (more commonly reported in children)

Serious reactions — including confusion, muscle twitching, slurred speech, irregular heartbeat, signs of serotonin syndrome (agitation, high fever, rapid heart rate, stiff muscles), or sudden vision changes — require immediate medical attention. Do not wait to see if they pass.

• Lithium toxicity: The gap between a therapeutic and a toxic blood level is very narrow. Tremor, nausea, confusion, unsteady walking, and slurred speech are early warning signs. Severe toxicity can cause seizures, coma, and permanent brain damage. Dehydration, low sodium, fever, and certain drugs can all tip levels into the toxic range quickly.
• Kidney effects: Long-term lithium use is associated with chronic kidney disease and a condition where the kidneys lose the ability to concentrate urine (nephrogenic diabetes insipidus). Kidney function must be monitored before and throughout treatment.
• Thyroid and parathyroid effects: Lithium can cause both hypothyroidism and, less commonly, hyperthyroidism. It is also linked to elevated calcium levels (hypercalcemia) and overactive parathyroid glands with long-term use. Regular thyroid and calcium monitoring is required.
• Brugada syndrome: Lithium can unmask a rare heart rhythm disorder. Tell your doctor immediately about unexplained fainting or palpitations, or a family history of sudden unexplained death before age 45.
• Encephalopathic syndrome: Combining lithium with antipsychotic medications raises the risk of a serious neurological reaction that, in some cases, has led to irreversible brain damage. Monitor closely for cognitive changes.
• Serotonin syndrome: A potentially life-threatening reaction can occur when lithium is combined with serotonergic drugs. Seek emergency care if symptoms develop.

Lithium interacts with a wide range of medications and substances — many of them commonly used — because its blood levels are so sensitive to changes in kidney function and sodium balance.

• Diuretics (water pills): Can lower sodium and reduce lithium clearance, pushing levels dangerously high.
• NSAIDs (ibuprofen, naproxen, etc.): Reduce kidney blood flow, decreasing how well lithium is cleared and raising blood levels.
• ACE inhibitors and ARBs (renin-angiotensin system drugs): Increase steady-state lithium levels; frequent monitoring needed.
• Antipsychotics: Increase risk of neurological toxicity ranging from movement problems to neuroleptic malignant syndrome.
• Serotonergic drugs (SSRIs, SNRIs, MAOIs, tramadol, triptans, St. John's Wort, fentanyl, buspirone): Can trigger serotonin syndrome — a medical emergency.
• Metronidazole (antibiotic): Reduces kidney clearance of lithium, raising blood levels.
• SGLT2 inhibitors (certain diabetes medications): Can lower lithium levels, potentially reducing effectiveness.
• Iodide preparations: Combining with lithium can cause hypothyroidism.
• Calcium channel blockers: Can increase the risk of neurological side effects including tremor and ataxia.
• Neuromuscular blocking agents: Lithium may prolong their effects, leading to prolonged muscle paralysis.

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Kidney disease: Lithium is cleared entirely by the kidneys — impaired kidney function raises toxicity risk significantly. Lithium should not be used in severe renal impairment.
• Pregnancy: Lithium may harm the fetus, including potential cardiac malformations with first-trimester exposure. If continued during pregnancy, blood levels must be closely monitored, and the dose may need to be lowered or stopped before delivery.
• Breastfeeding: Not recommended — lithium passes into breast milk at levels that can cause toxicity in infants. If a woman chooses to breastfeed, the infant must be closely monitored.
• Children under 7: Safety and effectiveness have not been established for this age group.
• Older adults: More likely to have reduced kidney function; start at lower doses and monitor carefully.
• History of heart rhythm problems or unexplained fainting: Lithium can unmask Brugada syndrome — a cardiology consult is recommended before starting if risk factors are present.
• Low sodium diet or dehydration: Dramatically increases the risk of lithium toxicity; maintain normal salt intake and stay well hydrated.
• Hypersensitivity: Do not take lithium if you have a known allergy to any inactive ingredient in the specific lithium product prescribed.

Lithium levels above 1.5 mEq/L are considered toxic, and levels above 3 mEq/L can lead to seizures, coma, and irreversible brain damage. There is no specific antidote. If overdose is suspected, call the Poison Control Center at 1-800-222-1222 or go to the nearest emergency room immediately. In severe cases, hemodialysis (a kidney dialysis machine) is the most effective way to rapidly remove lithium from the body.

After taking lithium by mouth, it is completely absorbed in the upper gastrointestinal tract. Immediate-release forms reach peak blood levels in as little as 15 minutes to 3 hours; extended-release forms take 2 to 6 hours to peak. Lithium is not broken down by the liver at all — it is eliminated unchanged by the kidneys. About 80% of the lithium filtered by the kidneys is reabsorbed, and its half-life (the time it takes for half the drug to leave the body) is approximately 18 to 36 hours. In children, how quickly the body clears lithium depends significantly on body weight, so dosing for pediatric patients is adjusted accordingly.

Store and Dispense Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Dispense in a tight, child-resistant container as defined in the USP/NF. Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).