RESUMO
Lithium may be used as adjuvant therapy in schizophrenic patients and antipsychotics can be employed during the early phases of lithium therapy in patients with bipolar disorder. The issue of interactions between lithium and antipsychotics is therefore important. This study investigates the potential influence of repeated administration of amisulpride, an atypical antipsychotic, on the pharmacokinetics of lithium at steady state. Twenty-four healthy male volunteers (aged 1833 yr) received lithium carbonate (500 mg b.i.d.) for 14 d. All subjects were shown to have stable lithium serum concentrations after 57 d and were then randomized to receive double-blind administration of amisulpride (100 mg b.i.d.) or placebo bid from day 8 of lithium administration. Complete pharmacokinetic profiles were obtained on days 7 and 14 for lithium and trough plasma concentrations on days 10, 12 and 14 for amisulpride. Co-administration of amisulpride appeared to exert no effect on the pharmacokinetics of lithium. All treatments were well tolerated and safety assessment revealed no differences between the lithium+placebo and lithium+amisulpride groups. This finding permits the flexible use of amisulpride in patients already receiving lithium therapy.