THE EFFECT OF MIANSERIN HYDROCHLORIDE ON DELIRIUM

Mianserin HCl (10-60 mg/day) was administered orally before bedtime to 46 patients (mean age: 63 years) with delirium at Kurume University Hospital. The therapeutic effects of mianserin were assessed pre- and post-treatment using the Delirium Rating Scale (DRS: Trzepacz et al., 1988). The mean pre-treatment DRS score was 21. This score decreased significantly (p<0.05) to 14 on treatment day 1 and 10 on day 3. Mianserin was observed to be effective in 85 per cent of the cases (marked improvement in 67 per cent of the patients and slight improvement in 17 per cent). Of the 46 patients, 28 were classified with delirium due to direct causes such as a brain tumour or cerebrovascular disease, and 18 due to facilitating factors such as hospitalization or physical restraint. In the former group, marked improvement was observed in 54 per cent of the patients, and slight improvement in 21 per cent. The latter group demonstrated marked improvement in 89 per cent of the patients, and slight improvement in 11 per cent. In control subjects receiving haloperidol, marked improvement was observed in 62 per cent of 17 delirious patients. The plasma concentration of mianserin reached a therapeutic level within 24 h of the initiation of treatment. Hence, based on these clinical results and on measurements of plasma mianserin concentrations, mianserin can be considered effective in the treatment of delirium in elderly patients due to its rapid onset and few side-effects. Mianserin may offer an efficacy similar to that of haloperidol in the treatment of delirium while being safer.