A controlled release (CR) formulation of remoxipride (Roxiam(®), Astra) given once-daily was compared to immediate release (IR) remoxipride given twice-daily, with respect to efficacy and tolerability, in a 4-week multicentre parallel-group dose titration (200-600 mg/day) study with acutely ill schizophrenic patients. Forty- three patients received remoxipride CR (mean dose 344 mg/day) and 49 patients received remoxipride IR (mean dose 346 mg/day). Efficacy was assessed using the Kolakowska version of the Brief Psychiatric Rating Scale (BPRS score of ≥ 18 points at entry) and the Clinical Global Impression scale (CGI), while extrapyramidal symptoms were rated using the Simpson and Angus scale. Both formulations of remoxipride produced clinical improvement, with the BPRS median total score falling from 35 at baseline to 16 at last rating in the remoxipride CR group, and from 33 to 12.5 in the remoxipride IR group. More than 70% of the patients in both groups were assessed as 'much improved' or 'very much improved' according to the CGI scale. Both formulations of remoxipride were well-tolerated, with a low incidence of treatment-emergent adverse symptoms, including extrapyramidal side effects. No statistically significant differences were detected between the treatment groups with regard to efficacy, safety or tolerability.