Double-blind comparison of the side-effect profiles of daily versus alternate-day dosing schedules in lithium maintenance treatment of manic-depressive disorder

The side-effect profiles of daily vs. alternate-day lithium carbonate dosing schedule were compared in a double-blind study of 50 manic-depressive patients. Following a 3-month period on daily lithium maintenance treatment the patients were randomly allocated to daily or alternate-day lithium dosing aiming at maintaining the same 12-h serum concentration as prior to allocation (median 0.7 mmol/1). The daily and alternate-day median lithium doses were 700 mg and 1200 mg, respectively. There was no significant correlation between changes in the side-effect scores on the UKU side-effect rating scale and lithium dosing schedule (ordinal logistic regression), although analysis revealed a trend in favour of alternate-day dosing with respect to polyuria/polydipsia and diarrhoea (loose stool). The study thus lends no support to the hypothesis that lithium-related side-effects can be diminished by extending the interval between lithium doses from 1 to 2 days.