The effects of ziprasidone on steady-state lithium levels and renal clearance of lithium

Aims To assess the potential of ziprasidone to alter the renal clearance an d steady-state serum levels of lithium. Methods Healthy subjects who had stable serum lithium levels during the fir st 7 days of treatment with lithium 900 mg day(-1), given as two divided da ily doses, were randomized to receive concomitant treatment with either zip rasidone, 40 mg day(-1) given as two divided daily doses, on days 9-11 foll owed by 80 mg day(-1) given as two divided daily doses on days 12-15 (n = 1 2), or placebo twice daily (n = 13). Ziprasidone or placebo was administere d 2 h before each dose of lithium. Results Ziprasidone administration was associated with a 0.07 mmol 1(-1) (1 3%) mean increase in steady-state serum lithium levels compared with a mean increase of 0.06 mmol 1(-1) (10%) with placebo. Mean renal clearance of li thium decreased by 0.091 h(-1) (5%) in the ziprasidone group and by 0.141 h (-1) (9%) in the placebo group. None of these differences between the two g roups was statistically or clinically significant. Conclusions Ziprasidone does not alter steady-state serum Lithium concentra tions or renal clearance of lithium.