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.

Antidepressant Tapering Is Not Routine But Could Be.

INTRODUCTION: When antidepressants are discontinued, severe withdrawal symptoms are possible. Some patients have few or no problems stopping, whereas others struggle. That struggle can be minimized or prevented with careful dose tapering. How often is that done? METHODS: Using 7 years of medical records, we determined the percentage of patients who received a prescription for the lowest available dose of their antidepressant before it was discontinued, as an indicator of a deliberate taper. RESULTS: Over that period, 8.9% of patients had evidence of tapering. The percentage increased from 4.9% in 2014 to a plateau around 10% in the past 4 years. DISCUSSION: While reports of severe withdrawal are increasingly recognized and must be addressed, our data suggest that many patients can discontinue their antidepressants without a taper through the lowest dose. However, it is difficult to identify which patients will struggle without a careful taper. A "one-size-fits-all" taper approach is recommended, balancing the need for withdrawal prevention with the need to avoid unnecessary complexity for the majority of patients. The first decrement is key for all patients: it must go well. Thereafter many patients may accelerate but all should receive a prescription for the lowest available dose of their antidepressant.