Interactions between hydrochlorothiazide and Lithonate (lithium)
lithium and hydrochlorothiazide (Major Drug-Drug)
GENERALLY AVOID: Thiazide diuretics may cause a rapid increase in serum lithium levels and potentiate the risk of lithium toxicity. The exact mechanism is unknown but may be related to the sodium loss induced by thiazide diuresis, which produces a compensatory increase in proximal tubular reabsorption of sodium along with lithium. In a study of 22 patients receiving bendroflumethiazide 2.5 mg or hydroflumethiazide 25 mg daily for the treatment of edema, mean renal clearance of a single 600 mg dose of lithium carbonate was reduced by 24% during thiazide diuretic therapy compared to before or after diuretic therapy. A similar reduction in renal lithium clearance has been reported in studies with chlorothiazide. There have also been case reports of patients developing lithium toxicity shortly after initiation of various thiazide diuretics including bendroflumethiazide, chlorothiazide, chlorthalidone, hydrochlorothiazide and indapamide, either alone or in combination with other diuretics. Up to severalfold increases in serum lithium levels have been observed, usually within several days to 2 weeks but occasionally longer. The risk for lithium toxicity may be further increased during concomitant sodium restriction.
MANAGEMENT: Thiazide diuretics should generally not be prescribed to patients receiving lithium unless close monitoring of serum lithium levels and electrolytes can be rendered. Lithium dose reductions may be required. Patients should be advised to notify their physician if they experience potential signs and symptoms of lithium toxicity such as drowsiness, dizziness, muscle weakness, vomiting, diarrhea, thirst, polyuria, tinnitus, tremor, ataxia, and blurred vision. Some investigators have suggested that loop diuretics are safer with lithium than thiazide diuretics, although supporting data are limited.
