Adjunctive Dopamine Agonists in Treatment-resistant Bipolar II Depression: an Open Case Series

Objective: Previous studies and case observations have suggested that dopamine agonists (DAAs) such as pramipexole (PPX) and ropinirole (RPN) might be effective for major depression, but their adjunctive use in treatment-resistant bipolar II depression has not yet been specifically addressed.

Method: A chart review was conducted on 18 patients with a DSM-III-R bipolar NOS (Bipolar II) major depressive episode who were admitted to the day-hospital of the Department of Psychiatry at the University of Pisa. DAAs were added to ongoing treatments with conventional antidepressants and mood stabilizers to which patients had no responded after a period of at least 8 weeks. Clinical state and adverse effects were assessed at each visit. Final improvement in CGI scores of 1 or 2 were considered as responders.

Results: Mean DAA trial duration was 17.6 (sd = 7.8, range 4-34) weeks, with a mean final dose of 1.23+/-0.32 mg/day (range, 0.75-1.50mg/day) for PPX, and 2.97+/-0.99mg/day (range, 1.50-5.00mg/day) for RPN. DAAs were well tolerated and did not show any negative interaction with concomitant psychotropic medications. Only one patient became worse (final CGI = 5), and had to interrupt PPX due to nausea, increased agitation and irritability. Eight patients (44.4%) were considered responders (4 with PPX and 4 with RPN): 5 showed marked improvement (CGI = 1), and 3 showed moderate improvement (CGI = 2); another 5 (27.8%) manifested a transient response not sustained up to the end. The initial and final scores of CGI severity scale for all patients (responders and non-responders combined) were, respectively, 5.33+/-0.7 and 3.94+/-1.3 (mean +/- S.D). The mean change according to the CCI severity scale was statistically significant (t=4.74. p < 0.0002).

Conclusion: From the results, PPX and RPN appear to be well tolerated and potentially useful in the adjunctive treatment of drug-resistant bipolar II depression.