Bipolar disorder (previously referred to as manic depressive disorder) is a severe psychiatric disorder where an individual has extreme fluctuations in mood. These fluctuations vary from mania or hypomania (extreme periods of being “up”) and depression (extreme periods of being “down”).
Bipolar disorder is a treatable condition and the primary approach to treating bipolar disorder is use of medications. Medications used in the treatment of bipolar disorder include:
- Mood stabilizers: These medications are designed to stabilize issues with mania and assist in the treatment of depression. Lithium is a mood stabilizer that has been traditionally used in the treatment of bipolar disorder. Others include drugs that were originally used to treat epilepsy, such as Tegretol, Lamictal, and Depakote.
- Antipsychotic medications: These medications were originally used for the treatment of psychosis (e.g., schizophrenia), but they are also used for the treatment of bipolar disorder. The atypical antipsychotics are more often than bipolar disorder. These drugs include drugs like Risperdal and Zyprexa.
- Antidepressant medications: Antidepressants may be added to mood stabilizers or antipsychotic medications for the treatment of the depressive phase of bipolar disorder.
- Other medications: Depending on the individual’s presentation, other medications may also be added, such as benzodiazepines to treat issues with anxiety.
- Therapy and counseling: While not the primary treatment for bipolar disorder, therapy is typically added to medication treatment to help the individual comply with their treatment, learn functional coping strategies, deal with substance use issues, etc.
Lithium is a prescription medication that is one of the older medications used for the treatment of bipolar disorder. Lithium is no longer prescribed as often is it once was for the treatment of bipolar disorder and related disorders because other mood stabilizers have fewer side effects and are at least as effective as lithium.
The mechanism of action for the medication is not well understood. Lithium is actually a soft metal and also found in other products, including batteries, soldering products, and other industrial products.
As a medication, lithium is sold under various different brand names that include Eskalith, Eskalith CR, Lithobid, and Lithate. There are immediate-release and extended-release forms of the drug.
When used therapeutically, lithium levels are checked by blood tests that observe the amount of lithium in an individual’s blood as opposed to maintaining or taking a specific dose of the drug. Therapeutic levels of lithium are typically reported as being between 0.04 to 0.08 millimoles of lithium per liter of blood (mmol/l). Patients taking lithium have regular blood tests to ensure that they are at a therapeutic level, and the amount of the drug a person needs is based on the ability to maintain therapeutic levels of the drug in the person’s bloodstream.
Overdose effects can occur at as low as 1.0 mmol/l in some people. The window between a therapeutic dose and an overdose or potential lethal dose can be quite narrow. Doses are typically between 900 mg and 1200 mg per day, but again, the level of the drug in the blood is monitored and a dose that maintains that level is used.
Lithium has numerous interactions with other drugs. The potential toxic effects of lithium can be enhanced by using numerous other drugs.
Types of Lithium Toxicity (Overdose)
Doses of lithium for those with bipolar disorder are determined by the person’s gender, weight, and other variables, and the therapeutic level of the drug in a person’s system.
There are three types of toxicity or overdoses to lithium:
- Acute lithium toxicity (acute overdose): Acute toxicity occurs when a person takes too much of a drug in one setting or in a very short period of time. This would be what is considered an overdose by most sources.
- Chronic lithium toxicity (chronic overdose): Chronic toxicity occurs over a lengthy period of time when a person takes too much lithium, but not enough to cause significant immediate effects. Over time, the buildup of the drug produces toxic results.
- Acute-on-chronic toxicity: This situation occurs as a combination of both types of lithium toxicity.
Symptoms of Lithium Toxicity/Overdose
According to Rosen’s Emergency Medicine, symptoms can be different for acute and chronic overdose cases (toxicity cases). The symptoms of acute lithium toxicity include:
- Gastrointestinal issues: It is common for people to experience gastrointestinal issues with an acute overdose of lithium that include nausea, stomach pains, vomiting, and diarrhea.
- Cardiovascular symptoms: These may also occur and can include heartbeat irregularities, changes in blood pressure, dizziness, and syncope (fainting). Heart failure may occur in severe cases.
- Renal or kidney issues: Depending on the amount of the drug ingested, an individual may develop issues with kidney failure that complicate recovery.
- Central nervous system (neurological) symptoms: Individuals may also express central nervous system symptoms that can include tremors in the hand, a lack of coordination (particularly in the arms and legs), slurred speech, uncontrollable eye movements, muscle twitches, mental confusion, a loss of consciousness or a comatose state, and seizures. Seizures can be potentially fatal.
Symptoms associated with chronic lithium toxicity include:
- A lack of gastrointestinal issues: Chronic lithium toxicity is generally not associated with gastrointestinal problems.
- Kidney failure: Chronic lithium toxicity is associated with renal failure in many cases, depending on the length of time the exposure continues.
- Neurological symptoms: Neurological symptoms are predominant in cases of chronic lithium toxicity. These often include increased reflexes, slurred speech, tremors (particularly in the hands), problems with memory, and psychotic behavior (disturbed thought processes, hallucinations, and/or delusions).
The symptoms of acute-on-chronic lithium toxicity will often be a combination of acute symptoms and more chronic symptoms, and they will often include gastrointestinal and neurological symptoms.
What to Do if a Lithium Overdose Is Suspected
Obviously, lithium toxicity can be serious and potentially fatal due to significant neurological issues or kidney failure that can occur. Seizures can be fatal. In cases of acute toxicity (acute overdose), one should call 911; in cases of suspected chronic toxicity, one should discuss the situation with their prescribing physician.
Emergency services may ask for some information when an acute overdose is suspected. This information includes:
- The person’s age, weight, and overall health condition
- The name of the product that was ingested, including the dosage per pill and how much was ingested
- The time the product was ingested
- If the medication was prescribed for the person who took it and what it was prescribed for
During treatment, the treatment provider will monitor the person’s vital signs and address any specific symptoms that are displayed. Some of the potential treatments include:
- IV fluids
- Activated charcoal, particularly if other drugs or substances were taken along with lithium
- Blood and urine tests to measure lithium levels and the presence of other drugs
- An electrocardiogram to measure heart activity (EKG)
- Other medicines to treat specific symptoms
- Kidney dialysis in acute and chronic cases
The outlook for the person depends on how much lithium they used and how quickly they were able to get help. The goal of treatment is to avoid issues with renal failure and central nervous system symptoms and to address and reverse these symptoms as quickly as possible if they occur. Sometimes individuals who have tremors and other central nervous system symptoms may continue to display these symptoms even after treatment has been completed.
Individuals who experience seizures can potentially die, and extremely high doses/levels of lithium are potentially fatal. Chronic exposures are often very difficult to detect, and if left unchecked for too long, there may be permanent damage.