Diuretics lithium contraindication

Lithium is a drug with a narrow therapeutic index and therefore plasma concentrations are regularly monitored. Lithium is used in the prophylaxis and treatment of mania. Concurrent administration of lithium and diuretics, particularly the thiazides, is contraindicated as lithium excretion is reduced, resulting in increased plasma-lithium concentration and hence toxicity. 

As noted earlier, lithium is contraindicated in patients with unstable congestive heart failure or the sick sinus node syndrome ( 307, 328). In older patients or those with prior cardiac histories, a pretreatment ECG should be obtained. Except for the potential adverse interactions with diuretics, the concomitant use of other cardiac drugs is generally safe. Because verapamil may lower serum levels of lithium, however, more careful monitoring may be required to assure continued therapeutic effects (329). Some data also indicate that verapamil may predispose to lithium neurotoxicity. Conversely, increased lithium levels leading to toxicity has occurred with methyidopa and enalapril. When antihypertensive therapy is necessary, b-blockers are a reasonable choice when lithium is coadministered. 

Lithium and Diuretics. Sodium depletion is known to increase lithium toxicity, and it is generally recommended that lithium not be used in patients on diuretic therapy or on a sodium-restricted diet. Even protracted sweating or diarrhea can cause sufficient depletion of sodium to result in decreased lithium tolerance. The sodium depletion caused by diuretics reduces the renal clearance and increases the activity of lithium. However, if preferable therapeutic alternatives are not available, concurrent therapy need not be contraindicated as long as the interaction is recognized and appropriate steps are taken to monitor therapy and adjust the dosage. 

ACE inhibitors are absolutely contraindicated in pregnancy (see Pregnancy section under Special Populations ) and in patients with a history of angioedema. Similar to diuretics, ACE inhibitors can increase lithium serum concentrations in patients on lithium therapy. Concurrent use of an ACE inhibitor with a potassium-sparing diuretic (including aldosterone antagonists), potassium supplements, or an ARB may result in excessive increases in potassium. 

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