Randomised placebo controlled trial of Pramipexole addition to mood stabilisers for treatment resistant bipolar depression

PAX-BD is a major trial examining a novel treatment for bipolar disorder, funded by the National Institute for Health Research’s (NIHR) Health Technology Assessment (HTA) Board. The study is being led from Newcastle, but patients will be recruited from other sites across the country, including Glasgow, Nottingham, Oxford, and London.

Over a lifetime, 2.5% of people will suffer from bipolar disorder. Sufferers can have great difficulty in leading a normal life and BD is associated with a 10 year reduction in life expectancy. NICE recommends ‘mood stabiliser’ treatments, such as lithium and valproate, to make episodes of elevated and depressed mood less likely. If, despite such treatment, depression occurs, a second (additional) medication is recommended: quetiapine, olanzapine, or lamotrigine. Unfortunately, bipolar depression often does not respond to these treatments and many of these drugs have side effects, including sedation and weight gain. Pramipexole is currently used as a treatment for Parkinson’s disease and its safety and side effects are well known. Two studies suggest that it helps to treat bipolar depression but these studies were small and only lasted 6 weeks.

The aim of PAX-PD is to determine whether pramipexole, added on to mood stabilisers, is a cost effective treatment for patients with bipolar disorder whose depression has not responded to NICE recommended treatment. We will examine this drug compared to placebo (dummy tablets) over 12 months.

Who can take part?

  • Have a diagnosis of bipolar disorder (type I or II) and have not responded to at least two NICE recommended treatments for bipolar
  • Are currently depressed
  • Aged 18 or over
  • Do not have severe substance use disorder
  • Do not have current psychotic symptoms
  • Do not have contraindication to pramipexole
  • Do not have history of eye, cardiovascular, or renal disease
  • Are not on antipsychotics at randomisation
  • Are not pregnant, breast feeding, or a woman planning on getting pregnant in the near future
  • Are not starting specific psychotherapy from 4 weeks before randomisation through to week 12 of the study

For more information about the study please visit the main study website:

Visit PAX-BD study website