Pramipexole Augmentation for Treatment-Resistant Unipolar Depression Not Responding to Aripiprazole Augmentation

Background: At least 50% of patients with treatment-resistant depression (TRD) fail to respond to antidepressant augmentation with aripiprazole (AA), currently the augmentation strategy with the best evidence of efficacy. The present observational study investigated whether pramipexole augmentation (PA) might be useful for patients who failed AA. Methods: We compared the short- and long-term effectiveness and safety of PA in 81 consecutively recruited unipolar patients with TRD, 58 (71.6%) not previously treated with AA (UAA) and 23 (28.4%) who previously failed AA (FAA). Results: The FAA and UAA groups did not differ significantly in terms of remission, response, improvement, and general functioning at 12 and 24 weeks and in terms of freedom from relapse at 12 and 24 months. The response rates at 24 weeks were 69.6% (n = 16) and 77.6% (n = 45), and the remission rates were 60.9% (n = 14) and 74.1% (n = 43), respectively. The rates of sustained response at 24 months were 72.7% (n = 8) and 84.2% (n = 16), respectively. The 2 groups did not differ significantly on safety outcomes (acceptability, tolerability, suicidality and suicide attempts) in the short and long term. Conclusions: Our study showed that the off-label use of PA may be a promising treatment for patients with unipolar TRD who had previously failed respond to AA. The present findings are preliminary and should be interpreted with caution due to study limitations, including the flexibility of the add-on schedule and the small sample size of patients followed up for 12 and 24 months, and need to be confirmed in larger studies.