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Lithium

Also known as: [Often referred to by brand name (see MedlinePlus Drug Information)]
Formal name: Lithium
Related tests: Therapeutic drug monitoring, Emergency and Overdose Drug Testing, BUN, Creatinine, TSH

At a Glance

Why Get Tested?

To determine lithium levels in the blood in order to maintain a therapeutic level or to detect lithium toxicity

When to Get Tested?

When beginning treatment with lithium as the dose is adjusted to achieve therapeutic blood levels; at regular intervals to monitor lithium levels; as needed to detect low or toxic concentrations

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

This test measures the amount of lithium in the blood. Lithium is one of the most well-established and widely-used drugs prescribed in the treatment of bipolar disorder. Bipolar disorder is a mental condition that is characterized by alternating periods of depression and mania. These periods may be as short as a few days or weeks or may be months or years long. During a depressive episode, those affected may feel sad, hopeless, worthless, and lose interest in daily activities. They may be fatigued but have trouble sleeping, experience weight loss or gain, have difficulty concentrating, and have thoughts of suicide. During a manic episode, those affected may be euphoric, irritable, have high energy and grandiose ideas, use poor judgment, and participate in risky behaviors. Sometimes affected people will have mixed episodes with aspects of both mania and depression. Bipolar disorder can affect both adults and children.

Lithium is prescribed to even out the moods of a person with bipolar disorder; it is often called a "mood stabilizer" and is sometimes prescribed for people with depression who are not responding well to other medications. It is a relatively slow-acting drug and it may take several weeks to months for lithium to affect a person's mood. Dosages of the drug are adjusted until a steady concentration in the blood that is within therapeutic range is reached. The actual amount of drug that it will take to reach this steady state will vary from person to person and may be affected by a person's age, general state of health, and other medications that they are taking.

Lithium levels are monitored on a regular basis because blood levels must be maintained within a narrow therapeutic range. Too little and the medication will not be effective; too much and symptoms associated with lithium toxicity may develop, such as nausea, vomiting, diarrhea, confusion, and tremors. Extremely high levels can lead to stupor, seizures, and can be fatal.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed. However, timing of the sample collection may affect results. Generally, lithium blood levels are performed 12-18 hours after the last dose (also known as a "trough" level). Tell the laboratorian who is drawing your blood when you took your last dose so that the results can be interpreted correctly.

The Test

How is it used?

The lithium test is used to measure and monitor the amount of lithium in the blood in order to determine whether drug concentrations are in the therapeutic range. It may be used to measure blood levels every few days when a person first begins taking lithium to help adjust the dose and reach the desired blood level. The test may be used at regular intervals or as needed to monitor blood concentrations. One or more lithium tests may be ordered if a person starts taking additional medications to judge their effect, if any, on lithium levels and may be ordered if the doctor suspects toxicity.

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When is it ordered?

Lithium is ordered frequently when a person is starting lithium treatment or returning to it after an absence. Once stable blood concentrations in the therapeutic range have been achieved, then lithium may be monitored at regular intervals to ensure that drug levels remain in this range.

The test may be ordered when a person's condition does not appear to be responding to lithium to determine whether concentrations are too low, the medication is ineffective, and/or to determine if the person is complying with therapy (taking the lithium regularly). It may also be ordered when someone experiences a troublesome level of side effects and/or exhibits symptoms that the doctor suspects may be due to toxicity. Some signs and symptoms of lithium toxicity include:

  • Drowsiness, lack of energy
  • Muscle weakness
  • Lack of coordination
  • Slurred speech
  • Nausea, vomiting and/or diarrhea
  • Confusion
  • Irregular tremors or shaking

Blood samples for lithium levels are generally drawn 12-18 hours after the last dose. Since dosage timing varies and some formulations are time-released, collection specifics may vary.

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What does the test result mean?

The therapeutic range for lithium has been established at 0.6 - 1.2 mmol/L. Within this range, most people will respond to the drug without symptoms of toxicity. Response and side effects will be individual, however. Some people's bipolar condition will not be adequately treated at the low end of the therapeutic range and some people will experience excessive side effects at the upper end. People  should work closely with their doctor to find the dosage and concentration that works the best for them.

In general, when lithium results are in the therapeutic range and the doctor and affected person are satisfied that the person's bipolar disorder is being appropriately managed, then the dosage of lithium is adequate, particularly if the person is not experiencing significant side effects. If the blood level is below the therapeutic range, it is likely that the affected person is not receiving adequate medication. If levels are above the therapeutic range and if there are significant side effects present at the current dose, then it is likely that the dose is too high. However, people should not decrease or stop taking their medication without consulting with their doctor as it can worsen their bipolar symptoms. Dosage determinations and adjustments must be evaluated on a case-by-case basis.

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Is there anything else I should know?

Lithium is excreted primarily by the kidneys. Long-term use of lithium carries a risk of decreased kidney function. People with kidney disease may have increased lithium levels because of decreased elimination. Doctors will monitor kidney function over time with tests such as a BUN and creatinine.

People who take lithium may develop hypothyroidism. Doctors will often regularly monitor a person's thyroid function with a TSH test.

A variety of prescribed drugs, over-the-counter medications, and supplements can increase, decrease, or interfere with the concentrations of lithium in the blood. Drugs that can increase lithium in the body include anti-inflammatories such as ibuprofen and naproxen and diuretics such as hydrochlorothiazide and furosemide. Drugs that can increase the side effects of lithium include antipsychotics such as clozapine and olanzapine, blood pressure medications such as calcium channel blockers and angiotensin converting enzyme inhibitors, and antiseizure medications such as carbamazepine. Drugs that can decrease lithium include theophylline and prescription levels of caffeine.

Lithium levels and side effects can increase with the loss of salt and water from the body, such as may occur with a salt-free diet, excessive sweating, or with an illness that causes vomiting and diarrhea.

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Common Questions

1.  How long will I need to be on lithium?

Lithium is usually taken every day for a person's lifetime. Bipolar disorder can be managed but not cured.

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2.  Who orders lithium tests?

They may be monitored by your primary doctor but may also be ordered and monitored by a mental health professional.

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3.  Can I test my lithium level at home?

No, the test requires specialized equipment. Most blood samples are collected from a vein in the arm and tested in the laboratory. However, the FDA has approved a test that can be performed in the doctor's office (it requires blood from a fingerstick). This test may not be widely available yet, but its use may become more common in the near future.

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Ask a Laboratory Scientist

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER and Bruns DE, eds. 4th ed. St. Louis, Missouri: Elsevier Saunders; 2006, Pp 1271-1272.

Harrison's Principles of Internal Medicine. 16th ed. Kasper D, Braunwald E, Fauci A, Hauser S, Longo D, Jameson JL, eds. McGraw-Hill, 2005 Pg 2557.

(Updated March 24, 2009) Lee D, Gupta M. Toxicity, Lithium from Medscape. Available online at http://emedicine.medscape.com/article/815523-overview through http://emedicine.medscape.com. Accessed September 2009.

(January 15, 2009) MedlinePlus Medical Encyclopedia. Bipolar Disorder. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000926.htm. Accessed September 2009.

(January 4, 2009) Mayo Clinic. Bipolar Disorder. Available online at http://www.mayoclinic.com/health/bipolar-disorder/DS00356 through http://www.mayoclinic.com. Accessed September 2009.

National Alliance on Mental Illness. Medications, Lithium. Available online through http://www.nami.org. Accessed September 2009.

(Jan 14, 2009) Lloyd A. Netdoctor: Lithium. Available online at http://www.netdoctor.co.uk/diseases/depression/lithium_000290.htm through http://www.netdoctor.co.uk. Accessed September 2009.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition]. Pp 1121.

Spearing, M. Updated (2006 February 17,Updated). Bipolar Disorder. NIMH [On-line information]. Available online at http://www.nimh.nih.gov/publicat/bipolar.cfm#bp6 through http://www.nimh.nih.gov.

Goldberg, J. and Citrome, L. (2005 February). Latest therapies for bipolar disorder, Looking beyond lithium. Postgraduate Medicine online v 117 (2) [On-line journal]. Available online at http://www.postgradmed.com/issues/2005/02_05/goldberg.htm through http://www.postgradmed.com.

Geddes, J. et. al. (2004 February). Long-Term Lithium Therapy for Bipolar Disorder: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Am J Psychiatry 161:217-222 [On-line journal]. Available online at http://ajp.psychiatryonline.org/cgi/content/full/161/2/217 through http://ajp.psychiatryonline.org.

Newport, D. J. et. al. (2005 November). Lithium Placental Passage and Obstetrical Outcome: Implications for Clinical Management During Late Pregnancy. American Journal of Psychiatry 162:2162-2170 [on-line abstract]. Available online at http://ajp.psychiatryonline.org/cgi/content/abstract/162/11/2162 through http://ajp.psychiatryonline.org.

Schapiro, N. (2005). Bipolar Disorders in Children and Adolescents. Medscape from J Pediatr Health Care. 2005; 19 (3): 131-141 [On-line information]. Available online at http://www.medscape.com/viewarticle/504584_1 through http://www.medscape.com.

Menon, L. (2005 August, Updated). Lithium. National Alliance for the Mentally Ill [On-line information]. Available online through http://www.nami.org.

Walling, A. (2005 January 1). Evidence-Based Guidelines for Bipolar Disorder Therapy. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20050101/tips/19.html through http://www.aafp.org.