Lithium is effective in the treatment of patients with mood disorders; however, it has a narrow therapeutic index and is associated with a number of significant toxicities including endocrinopathies. Routine monitoring for complications is indicated to enable timely lithium cessation or initiation of treatment.
- Thyroid and parathyroid dysfunction and nephrogenic diabetes insipidus (DI) are common in patients treated with lithium.
- For patients undergoing lithium therapy, thyroid function and calcium levels should be monitored at baseline, then every three to six months after starting treatment, and then every six to 12 months long term.
- Levothyroxine should be initiated in patients with overt hypothyroidism or enlarged goitre, or in asymptomatic patients with thyroid stimulating hormone (TSH) levels greater than 10.0 mU/L. It may also be initiated in symptomatic patients with a TSH level of 3.5 to 10 mU/L.
- Management of a patient with persistent hyperparathyroidism may include careful observation with vitamin D3 supplementation, surgical intervention or medical therapy with cinacalcet hydrochloride in patients with contraindications to surgery.
- In patients with suspected nephrogenic DI, the diagnosis should be confirmed with a water deprivation test.
- Cessation of lithium therapy should be considered for patients with early or overt nephrogenic DI and they should be monitored for hypernatraemia.
- Amiloride hydrochloride is first-line treatment for patients with confirmed nephrogenic DI but starting amiloride requires close monitoring of the serum lithium level and adjustment of lithium dosage.