Evaluation of thyroid function monitoring in people treated with lithium: Advice based on real-world data

Low and very low lithium levels: Thyroid effects are small but still require monitoring

AIM

Low doses of lithium, as might be used for mood or dementia prevention, do not carry the same renal, toxicity, and tolerability problems of doses used for prophylaxis or treatment of mania. However, thyroid effects of low doses have not been investigated. Our goal in this study was to assess the changes in thyroid-stimulating hormone (TSH) associated with a broad range of lithium levels, including those well below the therapeutic range for bipolar disorders.

METHODS

This study was conducted in a small healthcare system with 19 associated primary care clinics served by a Collaborative Care program of psychiatric consultation. In this retrospective review of electronic records, we searched for patients who had received a lithium prescription and both pre- and post-lithium thyroid-stimulating hormone (TSH) levels.

RESULTS

Patients with low lithium levels (<0.5 mEq/L, N = 197) had a mean thyroid-stimulating hormone (TSH) increase of 0.52 mIU/L. Patients with maintenance lithium levels (0.5-0.8 mEq/L; N = 123) had a mean TSH increase of 1.01 mIU/L; and patients with antimanic lithium levels (>0.8 mEq/L; N = 79) had a mean TSH increase of 2.16 mIU/L. The probability of TSH exceeding the upper limit of normal in our laboratory (>4.2 mIU/L) was positively associated with pre-lithium TSH.

CONCLUSION

These results suggest that the risk of lithium-induced hypothyroidism is dose-related, and relatively small with very low doses, but thyroid monitoring, including a pre-lithium TSH, is still warranted.

Updated perspectives on how and when lithium should be used in the treatment of mood disorders

INTRODUCTION

Lithium is one of the most important drugs for the treatment of mood disorders. The appropriate guidelines can ensure that more patients benefit from its use in a personalized way.

AREAS COVERED

This manuscript provides an update on the application of lithium in mood disorders, including prophylaxis of bipolar and unipolar mood disorder, treatment of acute manic and depressive episodes, augmentation of antidepressants in treatment-resistant depression, and use of lithium in pregnancy and the postpartum period.

EXPERT OPINION

Lithium remains the gold standard for the prevention of recurrences in bipolar mood disorder. For long-term treatment/management of bipolar mood disorder, clinicians should also consider lithium's anti-suicidal effect. Furthermore, after prophylactic treatment, lithium may also be augmented with antidepressants in treatment-resistant depression. There have also been some demonstration of lithium having some efficacy in acute episodes of mania and bipolar depression as well as in the prophylaxis of unipolar depression.