Five RCTs (n=1,034) were included in the review.
Quetiapine as monotherapy: There was evidence of comparable efficacy for quetiapine and lithium compared to placebo for change in Young Mania Rating Scale points, response and remission rates at days 21 and 84 (one RCT, n=302). However, lithium concentrations may have been suboptimal.
Participants (one RCT, n=302) receiving haloperidol showed a greater improvement at day 21 for the Young Mania Rating Scale total scores (minus 15.71 points) compared to those receiving quetiapine (minus 12.29 points) or placebo (minus 8.32 points). However, efficacy at day 84 was similar for haloperidol and quetiapine. There were no significant differences between quetiapine or haloperidol and placebo groups for remission rates at day 21. However, remission rates were better at day 84 for patients receiving haloperidol (63.3 per cent) and quetiapine (61.4 per cent) compared to placebo (38 per cent, p<0.001 for both comparisons).
Quetiapine as adjunctive therapy: One RCT (n=191) found a greater reduction in Young Mania Rating Scale scores at 21 days for patients receiving quetiapine (minus 13.76 points) than placebo (minus 9.93 points) as adjunct therapy to lithium or divalproex for adults with acute mania. However, there were no significant differences between groups for remission rates. A second RCT (n=209) found no significant differences at 21 days between groups receiving quetiapine or placebo as adjunct therapy to lithium or divalproex for change in Young Mania Rating Scale scores.
Quetiapine was found to be more effective than placebo as an adjunct to divalproex for the treatment of adolescents with mania (one RCT, n=30, Young Mania Rating Scale scores: minus 23 for quetiapine; minus 15 for placebo).
Adverse effects: The most common adverse effects experienced by participants receiving quetiapine were somnolence (34 per cent as monotherapy, 66 per cent as adjunct therapy) and dry mouth (33 per cent as monotherapy and 38 per cent as adjunct therapy). Higher rates of asthenia were reported for participants taking quetiapine as adjunct therapy (19 per cent) compared to placebo (eight per cent). Weight increases of seven per cent or more were found in 21 per cent to 39 per cent of patients receiving quetiapine as monotherapy compared to 9.5 per cent to 14 per cent of participants taking placebo. A similar weight gain was found for participants taking quetiapine as adjunct therapy (21 per cent) compared to participants taking placebo (7 per cent).