Thiazide-lithium synergy in refractory mood swings.

The unfortunate experience with lithium chloride as a salt substitute in the 1940s still directs the clinical usuage of lithium carbonate to a certain extent. We are still warned that lithium salts should never be used in low-sodium situations (e.g., with thiazide diuretics or salt-restricted diets); however, it has recently been shown that thiazide diuretics may be safely used in the treatment of lithium-induced nephrogenic diabetes insipidus (NDI). The authors recapitulate the dangers inherent in the use of this drug combination and present detailed clinical-pharmacologic data on 13 patients which suggest that thiazides are useful in the treatment of lithium-induced NDI and may actually synergize with lithium to produce improved mood control in some lithium-refractory manic-depressive patients.