Assessment of renal concentrating ability in lithium-treated patients. Comparison of long-term dehydration with administration of a vasopressin analogue.

In patients given long-term treatment with lithium maximum urine osmolality was measured after 26 h of dehydration and after intranasal administration of desamino-8-D-arginine vasopressin (DDAVP). A high correlation was found between the results of the two tests suggesting that the DDAVP test is a suitable method of assessing renal concentrating ability in lithium-treated patients.