Lithium has been used in psychiatry for more than half a century and is considered the gold standard for treating acute mania and maintenance treatment of bipolar disorder.1 Evidence supports its use to reduce suicidal behavior and as an adjunctive treatment for major depressive disorder.2 However, lithium has fallen out of favor because of its narrow therapeutic index as well as the introduction of newer psychotropic medications that have a quicker onset of action and do not require strict blood monitoring. For residents early in their training, keeping track of the laboratory monitoring and medical screening can be confusing. Different institutions and countries have specific guidelines and recommendations for monitoring patients receiving lithium, which adds to the confusion.
We completed a literature review to develop clear and concise recommendations for lithium monitoring for residents in our psychiatry residency program. These recommendations outline screening at baseline and after patients treated with lithium achieve stability. Table 13-11 outlines medical screening parameters, including bloodwork, that should be completed before initiating treatment, and how often such screening should be repeated. Table 2 incorporates these parameters into progress notes in the electronic medical record to keep track of the laboratory values and when they were last drawn. Our aim is to help residents stay organized and prevent missed screenings.
How often should lithium levels be monitored?
After starting a patient on lithium, check the level within 5 to 7 days, and 5 to 7 days after each dose change. Draw the lithium level 10 to 14 hours after the patient’s last dose (12 hours is best).1 Because of dosage changes, lithium levels usually are monitored more frequently during the first 3 months of treatment until therapeutic levels are reached or symptoms are controlled. It is recommended to monitor lithium levels every 3 months for the first year and every 6 months after the first year of treatment once the patient is stable and considering age, medical health, and how consistently a patient reports symptoms/adverse effects.3,5 Continue monitoring levels every 3 months in older adults; in patients with renal dysfunction, thyroid dysfunction, hypercalcemia, or other significant medical comorbidities; and in those who are taking medications that affect lithium, such as pain medications (nonsteroidal anti-inflammatory drugs can raise lithium levels), certain antihypertensives (angiotensin-converting-enzyme inhibitors can raise lithium levels), and diuretics (thiazide diuretics can raise lithium levels; osmotic diuretics and carbonic anhydrase inhibitors can reduce lithium levels).1,3,5
Lithium levels could vary by up to 0.5 mEq/L during transition between manic, euthymic, and depressive states.12 On a consistent dosage, lithium levels decrease during mania because of hemodilution, and increase during depression secondary to physiological effects specific to these episodes.13,14
Recommendations for plasma lithium levels (trough levels)
Mania. Lithium levels of 0.8 to 1.2 mEq/L often are needed to achieve symptom control during manic episodes.15 As levels approach 1.5 mEq/L, patients are at increased risk for intolerable adverse effects (eg, nausea and vomiting) and toxicity.16,17 Adverse effects at higher levels may result in patients abruptly discontinuing lithium. Patients who experience mania before a depressive episode at illness onsettend to have a better treatment response with lithium.18 Lithium monotherapy has been shown to be less effective for acute mania than antipsychotics or combination therapies.19 Consider combining lithium with valproate or antipsychotics for patients who have tolerated lithium in the past and plan to use lithium for maintenance treatment.20
Maintenance. In adults, the lithium level should be 0.60 to 80mEq/L, but consider levels of 0.40 to 0.60 mEq/L in patients who have a good response to lithium but develop adverse effects at higher levels.21 For patients who do not respond to treatment, such as those with severe mania, maintenance levels can be increased to 0.76 to 0.90 mEq/L.22 These same recommendations for maintenance levels can be used for children and adolescents. In older adults, aim for maintenance levels of 0.4 to 0.6 mEq/L. For patients age 65 to 79, the maximum level is 0.7 to 0.8 mEq/L, and should not exceed 0.7 mEq/L in patients age >80. Lithium levels <0.4 mEq/L do not appear to be effective.21
Depression. Aim for a lithium level of 0.6 to 1.0 mEq/L for patients with depression.11
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