Lithium Carbonate Risks, Warnings, and Complications

LITHIUM TOXICITY: Therapeutic concentrations of lithium are 0.8 to 1.2 mEq/L. Lithium intoxication or toxicity occurs when peak serum concentrations of lithium ions are 1.5 mEq/L or higher, which is not much higher than the therapeutic range. Additionally, geriatric patients and patients abnormally sensitive to lithium can develop signs of toxicity at serum concentrations ordinarily tolerated by most patients. 

Signs of lithium toxicity (too much lithium) may appear up to 24 hours later and can include lightheadedness, weakness, a fine hand tremor, and lack of coordination. More severe symptoms can include dizziness, drowsiness, muscle twitching, loss of balance and coordination, blurred vision, ringing in the ears, and slurred speech. People with severe lithium toxicity may develop nausea, vomiting, diarrhea, uncontrolled movements of the body, shortness of breath, electrocardiographic changes, confusion, seizures, and kidney failure. Rarely, lithium toxicity can result in permanent damage that persists even after the medication is stopped. It can be fatal in severe cases. 

There is no specific antidote for lithium poisoning except treatment discontinued promptly. Risk factors include recent or concurrent febrile illnesses, concurrent use of other drugs that can increase serum lithium concentrations as a result of drug interactions, overdose, impaired renal function, dehydration or volume depletion, electrolyte abnormalities, and a history of cardiovascular disease.

Call your doctor immediately if you develop signs and symptoms of lithium toxicity, as listed above. Your doctor may decrease your dose to lower serum lithium concentrations or discontinue lithium therapy.

POLYURIA: Chronic lithium treatment can affect the renal concentrating ability, causing a condition called nephrogenic diabetes insipidus. This is characterized by polyuria (excessive urination) and polydipsia (excessive thirst). This complication can occur within weeks of starting lithium therapy. Kidney damage due to lithium carbonate use can also result in acute or chronic kidney disease. These changes are usually reversible early during lithium treatment but can become permanent with chronic lithium treatment. 

Dehydration, vomiting, diarrhea, a febrile illness, impaired renal function, excessive exercise, excessive sweating, a low sodium diet, and congestive heart failure are risk factors for kidney problems associated with lithium. Tell your doctor without delay if you develop any of the above signs and symptoms. 

HYPONATREMIA: Lithium can decrease the reabsorption of sodium in the kidneys and lead to hyponatremia (low sodium levels). Talk to your doctor about eating a normal diet that contains adequate amounts of salt (sodium chloride) and adequate fluid intake (2.5 to 3 liters per day), especially during the initial period of lithium stabilization. Excessive sweating, diarrhea, vomiting, and dehydration can lead to a decreased tolerance to lithium. 

Tell your doctor immediately if you develop symptoms such as mental status or personality changes, apathy, lethargy, or confusion. Severe hyponatremia can affect the nerve and muscle cells, causing overactive reflexes, muscle twitching, seizures, coma, and death. 

Your healthcare provider may need to give you supplemental salt and fluids under medical supervision if you develop these problems. They may also change you to a lower dose or stop lithium carbonate. 

CHRONIC KIDNEY DISEASE: Long-term lithium treatment can lead to kidney damage and a type of chronic kidney disease called chronic tubulointerstitial nephropathy (CTIN). Your doctor will check your kidney function before and during lithium therapy with routine urinalysis and other tests. Tell your doctor immediately if you develop any urinary symptoms during lithium treatment.

ENCEPHALOPATHIC SYNDROME: Lithium administration, along with an antipsychotic medication, can result in a condition called encephalopathic syndrome or neuroleptic malignant syndrome (NMS). This is a serious complication characterized by clinical signs such as fever, weakness, lethargy, shakiness, confusion, uncontrolled movements, increased white blood cell count, elevated serum enzymes, increased blood sugar levels, and increased BUN. It can sometimes lead to permanent brain damage. If you are on concomitant treatment with lithium and antipsychotics, your provider will monitor you closely for signs of neurological toxicity and discontinue treatment if they appear. 

SEROTONIN SYNDROME: Taking lithium carbonate can trigger a serious and potentially life-threatening condition called serotonin syndrome. The risk is higher if you are also taking other drugs that increase serotonin levels, such as antidepressant medications, triptans used for migraine treatment, opioid analgesics, and herbal products like St. John’s Wort. Signs and symptoms of serotonin syndrome may include changes in mental status (confusion, agitation, hallucinations, delirium, coma), fast heart rate, changes in blood pressure, dizziness, sweating, flushing, raised body temperature, tremors, muscle rigidity, uncontrolled muscle contractions, overactive reflexes, loss of coordination, seizures, nausea, vomiting, and diarrhea. Stop taking lithium carbonate if you develop any of these symptoms, and call your doctor immediately.

THYROID DISORDERS: With repeated daily dosing, lithium gets concentrated in the thyroid gland. The resulting lithium retention can lead to hypothyroidism (underactive thyroid). This may require supplemental thyroid treatment. In contrast, some patients develop hyperthyroidism (overactive thyroid), including thyroiditis, Grave’s disease, and toxic multinodular goiter. Your healthcare provider will monitor thyroid function before and during lithium therapy. 

HYPERPARATHYROIDISM AND HYPERCALCEMIA: Long-term treatment with lithium carbonate can lead to hyperparathyroidism (overactive parathyroid glands) and persistent hypercalcemia (high serum calcium levels). This may require stopping lithium therapy and changing to another medication for mood stabilization. These complications may not resolve after stopping lithium, and surgery may be needed. Your doctor will check serum calcium concentrations periodically during treatment.

BRUGADA SYNDROME: Brugada syndrome is a condition associated with abnormal electrocardiographic findings and an increased risk of sudden death. There are some reports of possible links between lithium therapy and the unmasking (discovery) of Brugada syndrome. If you have this condition, your doctor may avoid giving you lithium. If you have risk factors for this condition, your provider may send you to a cardiologist for consultation before starting lithium treatment. 

PSEUDOTUMOR CEREBRI: There are reports of pseudotumor cerebri (increased intracranial pressure and swelling of the optic discs) in patients treated with lithium. If this condition is not diagnosed, it can lead to loss of vision and eventual blindness. Your doctor will discontinue lithium if this complication occurs.

MALE FERTILITY: Lithium ions can cross the blood-testis barrier and reach the male reproductive organs. Long-term lithium therapy has been found to affect the development and release of sperm. Talk to your doctor about the pros and cons of lithium treatment if you are a male and plan to have children in the future.