Safety and Effectiveness of Lithium Therapy in Patients With Graves' Disease

Lithium is an established adjunct therapy in the management of hyperthyroidism, particularly when conventional antithyroid therapy is contraindicated. This study aimed to investigate its efficacy and safety in patients with Graves' disease. This retrospective observational study was conducted on 14 patients who received lithium due to intolerance or adverse reactions to thionamides. Paired-samples t-tests and linear mixed-effects models were used to assess changes in thyroid hormones, renal markers, urinary concentration and electrolytes after lithium therapy. Lithium was initiated primarily due to allergic (35.7%) or hepatotoxic reactions (28,6%) to thionamides and 64.2% of patients ultimately underwent surgery or radioactive iodine therapy. Following a median lithium exposure of 37 days, significant reductions were observed in free T4 (2.58 ± 1.48 vs. 1.42 ± 1.06 ng/dL; p = 0.004) and free T3 (7.37 ± 2.70 vs. 4.88 ± 2.04 ng/L; p = 0.009). Urinary density decreased significantly (p = 0.016), suggesting early renal tubular effects. No significant changes were observed in serum sodium, potassium, or creatinine. Despite individual cases presenting hypercalcemia, there was no statistically significant change following lithium use (Δ = -0.12; p = 0.643; LMM F = 0.437, p = 0.730). Lithium is effective in achieving rapid biochemical control of hyperthyroidism and may serve as a valuable bridging option for patients in whom antithyroid therapy is contraindicated or not tolerated. However, the potential for early renal concentration and calcium metabolism disturbances warrants vigilant monitoring.