Dr. Pelekanos is a PGY-4 Psychiatry Resident, Department of Psychiatry, Temple University Hospital, Philadelphia, Pennsylvania. Dr. Foo is a PGY-4 Psychiatry Resident, Department of Psychiatry, Temple University Hospital, Philadelphia, Pennsylvania.
Disclosures The authors report no financial relationships with any companies whose products are mentioned in this article, or with manufacturers of competing products.
Obtain a basic metabolic panel or comprehensive metabolic panel to establish baseline levels of creatinine, blood urea nitrogen (BUN), and estimated glomerular filtration rate (eGFR). Repeat testing at Week 12 and at 6 months to detect any changes. Renal function can be monitored every 6 to 12 months in stable patients, but should be closely watched when a patient’s clinical status changes.3 A new lower eGFR value after starting lithium therapy should be investigated with a repeat test in 2 weeks.23 Mild elevations in creatinine should be monitored, and further medical workup with a nephrologist is recommended for patients with a creatinine level ≥1.6 mg/dL.24 It is important to note that creatinine might remain within normal limits if there is considerable reduction in glomerular function. Creatinine levels could vary because of body mass and diet. Creatinine levels can be low in nonmuscular patients and elevated in patients who consume large amounts of protein.23,25
Ordering a basic metabolic panel also allows electrolyte monitoring. Hyponatremia and dehydration can lead to elevated lithium levels and result in toxicity; hypokalemia might increase the risk of lithium-induced cardiac toxicity. Monitor calcium (corrected serum calcium) because hypercalcemia has been seen in patients treated with lithium.
Thyroid function monitoring frequency
Obtain levels of thyroid-stimulating hormone with reflex to free T4 at baseline, 12 weeks, and 6 months. Monitor thyroid function every 6 to 12 months in stable patients and when a patient’s clinical status changes, such as with new reports of medical or psychiatric symptoms and when there is concern for thyroid dysfunction.3
Lithium and neurotoxicity
Lithium is known to have neurotoxic effects, such as effects on fast-acting neurons leading to dyscoordination or tremor, even at therapeutic levels.26 This is especially the case when lithium is combined with an antipsychotic,26,27 a combination that is used to treat bipolar I disorder with psychotic features. Older adults are at greater risk for neurotoxicity because of physiological changes associated with increasing age.28
Educate patients about adherence, diet, and exercise
Patients might stop taking their psychotropic medications when they start feeling better. Instruct patients to discuss discontinuation with the prescribing clinician before they stop any medication. Educate patients that rapidly discontinuing lithium therapy puts them at high risk of relapse29 and increases the risk of developing treatment-refractory symptoms.23,30 Emphasize the importance of staying hydrated and maintaining adequate sodium in their diet.17,31 Consuming excessive sodium can reduce lithium levels.17,32 Lithium levels could increase when patients experience excessive sweating, such as during exercise or being outside on warm days, because of sodium and volume loss.17,33
