Savvy Psychopharmacology Lithium-induced diabetes insipidus: Prevention and management Arnold Andreasen, PharmD Candidate, and Vicki L. Ellingrod, PharmD, FCCP r. H, age 33, was diagnosed with bipo- symptoms, such as polydipsia and polyuria, lar I disorder 9 years ago. For the past and is estimated to occur in approximately year, his mood symptoms have been 40% of patients receiving long-term lithium M 4,5 well controlled with lithium 300 mg, 3 times therapy. a day, and olanzapine, 20 mg/d. He presents to the outpatient clinic for a routine visit com- Diagnosis plaining of insomnia, daytime sleepiness, and Diagnosing lithium-induced nephrogenic Vicki L. Ellingrod, increased thirst. He also notes that his tremor diabetes insipidus (NDI) begins with a his- PharmD, FCCP has become more prominent over the last few tory of the patient’s symptoms and order- Series Editor weeks. Concerned about his symptoms, Mr. ing lab tests.5 The next step involves a wa- H’s clinician orders a comprehensive labora- ter restriction test, also known as a thirst tory panel (Table). test, to measure the patient’s ability to con- Upon further questioning, Mr. H’s physi- centrate his or her urine. Baseline serum cian determines that his insomnia is caused osmolality and electrolytes are compared by nocturnal urination, which is consistent with new values obtained after completing with fluid and electrolyte imbalances seen in the water restriction test. Healthy people Mr. H’s laboratory panel. Mr. H is diagnosed will have a 2-to-4-fold increase in urine os- with lithium-induced diabetes insipidus. molality compared with patients who have Although lithium’s exact mechanism of ac- tion is unknown, it is known that lithium Practice Points can negatively affect the kidneys.1,2 Typically, • Lithium-induced diabetes insipidus is caused by ADH resistance in the kidneys. antidiuretic hormone (ADH) regulates wa- ter permeability in the collecting duct of the • Educate patients about signs and nephron, allowing water to be reabsorbed symptoms of nephrogenic diabetes through simple diffusion in the kidney’s insipidus (NDI), such as polyuria and polydipsia. collecting duct (Figure, page 44).3 Chronic lithium use reduces or desensitizes the kid- • For all patients taking lithium, provide ney’s ability to respond to ADH. Resistance comprehensive lab monitoring at baseline and at least every 6 to 12 months. to ADH occurs when lithium accumulates in the cells of the collecting duct and inhibits • When a patient experiences NDI, consider ADH’s ability to increase water permeabil- discontinuing lithium, reducing the daily ity. This inhibition can cause some of Mr. H’s dosage, or reducing the dosing schedule. • Diuretics are a viable treatment option Mr. Andreasen is a PharmD Candidate, University of Michigan for NDI in patient’s receiving lithium. Close College of Pharmacy, and Dr. Ellingrod is the John Gideon monitoring of lithium and potassium Searle Professor of Clinical and Translational Pharmacy, and patient education about lithium are Current Psychiatry University of Michigan College of Pharmacy and School of essential. 42 July 2013 Medicine, Department of Psychiatry, Ann Arbor, MI. Savvy Psychopharmacology Table Mr. H’s lab panel with reference ranges Test Value Sodium 157 mEq/L (136 to 146 mEq/L) Potassium 4.5 mEq/L (3.5 to 5 mEq/L) Chloride 104 mEq/L (98 to 108 mEq/L) Bicarbonate 25 mEq/L (22 to 34 mEq/L) Creatinine 1.8 mg/dL (baseline 0.8 mg/dL) (0.7 to 1.3 mg/dL) Calcium 8.35 mg/dL (8.6 to 10.3 mg/dL) Blood glucose 135 mg/dL (<100 mg/dL) Urine osmolality 175 mOsm/kg (300 to 1300 mOsm/kg) Serum osmolality 365 mOsm/kg (269 to 298 mOsm/kg) Clinical Point Thyroid-stimulating hormone 0.86 mIU/L (0.4 to 4.0 mIU/L) Lithium-induced Serum lithium 1.7 mEq/L (0.6 to 1.2 mEq/L) NDI is thought to be dose-dependent and NDI. The last step includes administering quire monitoring every 3 months. Also, in- may be prevented desmopressin and differentiates between struct patients to monitor their urine out- by using the lowest central diabetes insipidus and NDI.6 put and educate them about the dangers effective lithium After desmopressin use, patients who of fluid and electrolyte imbalances and the have central diabetes insipidus will have a signs and symptoms of NDI, such as exces- dose >50% increase in urine osmolality, whereas sive thirst and urination.1,2 patients who have NDI will have <10% in- When a patient experiences lithium- crease in urine osmolality. This distinction is induced NDI, re-evaluate treatment and important because patients with central dia- dosage, including simplifying the dosing betes insipidus might have more severe dis- regimen or switching to once-daily dos- ease and might not benefit from measures ing, usually at bedtime. Once-daily dosing commonly used for lithium-induced NDI.7 results in a lower overall lithium trough, which might allow the kidneys more “drug- Prevention and management free” time.4,5 Additionally, 12-hour lithium Lithium-induced NDI is thought to be dose- levels are approximately 20% higher with dependent and may be prevented by using once-daily monitoring; continued monitor- the lowest effective dose of lithium for an in- ing is needed during this switch. Patients dividual patient. It is important that patients who have a moderate or severe form of lith- taking lithium receive basic electrolyte, he- ium-induced NDI may need to discontinue matologic, liver function, renal function, and lithium altogether. There are several options thyroid function tests at baseline and every for treating lithium-induced NDI in patients 6 to 12 months after the lithium regimen is who need to take lithium. Closely monitor stable. Additionally, lithium levels should be kidney function and lithium routinely with monitored frequently. The frequency of these these strategies. tests may range from twice weekly to every Discuss this article at 3 to 4 months or longer, depending on the Amiloride. This potassium-sparing diuretic www.facebook.com/ CurrentPsychiatry patient’s condition. This monitoring allows minimizes accumulation of lithium by in- the prescriber to quickly identify emerging hibiting collecting duct sodium channels. adverse effects. Studies have shown that amiloride can de- Patients with impaired renal function crease mean urine volume, increase urine os- and those with a urine output >3 liters a molality, and improve the kidneys’ ability to Current Psychiatry day are more susceptible to NDI and re- respond to exogenous arginine vasopressin.8 Vol. 12, No. 7 43 continued Savvy Psychopharmacology Figure Sites of action of medications on nephron Distal convoluted tubule: Site of action for hydrochlorothiazide Clinical Point Use of a thiazide Collecting duct: Site of action diuretic might for antidiuretic warrant decreasing hormone the lithium dose by Collecting duct: Site of action for as much as 50% to amiloride prevent toxicity © CREATIONS Thiazide diuretics produce mild sodium consume. Potassium and lithium levels depletion, which decreases the distal tu- must be monitored closely.9 bule delivery of sodium, therefore in- creasing water reabsorption in the collect- Nonsteroidal anti-inflammatory drugs ing duct. Hydrochlorothiazide has been (NSAIDs). These drugs’ ability to inhibit shown to reduce urine output by >50% in prostaglandin synthesis prevents pros- patients with NDI on a sodium-restricted taglandins from antagonizing actions of diet. Hydrochlorothiazide use requires ADH in the kidney. The result is increased careful monitoring of potassium and lith- urine concentration via the actions of ADH. ium levels. Use of a thiazide diuretic also Indomethacin has a greater effect than ibu- might warrant decreasing the lithium dose profen in increasing ADH’s actions on the by as much as 50% to prevent toxicity.9,10 kidney. Use of concomitant NSAIDs with lithium requires close monitoring of renal Low-sodium diet plus hydrochlorothia- function tests.11 zide. This route provides another option to decrease urine output during lithium- References 1. Ecelbarger CA. Lithium treatment and remodeling of the induced NDI. A reduction in urine output collecting duct. Am J Physiol Renal Physiol. 2006;291(1): has been shown to be directly proportional F37-38. 2. Christensen BM, Kim YH, Kwon TH, et al. Lithium treatment to a decrease in salt intake and excretion. induces a marked proliferation of primarily principal cells in rat kidney inner medullary collecting duct. Am J Physiol Renal Restricting sodium to <2.3 g/d is an ap- Physiol. 2006;291(1):F39-48. propriate goal for many patients to prevent 3. Francis SG, Gardner DG. Basic and clinical endocrinology. reoccurring symptoms, which is more than 7th ed. New York, NY: McGraw Hill; 2003:154-158. Current Psychiatry 4. Stone KA. Lithium-induced nephrogenic diabetes insipidus. 44 July 2013 the 3 g/d average that most Americans J Am Board Fam Pract. 1999;12(1):43-47. Savvy Psychopharmacology 5. Grünfeld JP, Rossier BC. Lithium nephrotoxicity revisited. Nat Rev Nephrol. 2009;5(5):270-276. Related Resources 6. Wesche D, Deen PM, Knoers NV. Congenital nephrogenic diabetes insipidus: the current state of affairs. Pediatr Nephrol. • Bedford JJ, Weggery S, Ellis G, et al. Lithium-induced neph- 2012;27(12):2183-2204. rogenic diabetes insipidus: renal effects of amiloride. Clin J 7. Rose BD, Post TW. Clinical physiology of acid-base and Am Soc Nephrol. 2008;3(5):1324-1331. electrolyte disorders. 5th ed. New York, NY: McGraw-Hill; • Lederer E. Lithium nephropathy. http://emedicine. 2001:754-759,782-783. medscape.com/article/242772-overview. 8. Batlle DC, von Riotte AB, Gaviria M, et al. Amelioration of polyuria by amiloride in patients receiving long-term lithium Drug Brand Names therapy. N Engl J Med. 1985;312(7):408-414.