OBJECTIVE: This study was designed to determine whether patients
maintained on a regimen of lithium on a once-per-day schedule have lower
urine volumes than do patients receiving multiple doses per day. METHOD:
This was a cross-sectional study of 85 patients from a lithium clinic who
received different dose schedules. Patients were admitted to the hospital
for measurement of lithium level, creatinine clearance, urine volume, and
maximum osmolality. RESULTS: Multiple daily doses of lithium were
associated with higher urine volumes. The dosing schedule, duration of
lithium treatment, and daily dose of lithium did not affect maximum
osmolality or creatinine clearance. CONCLUSIONS: Urine volume can be
reduced by giving lithium once daily and/or by lowering the total daily
dose. Lithium-induced polyuria seems to be related to extrarenal as well as
to renal effects.Abstract Teaser