An unavoidable limitation of the study, the researchers noted, is that tamoxifen(Drug information on tamoxifen) is not entirely protein kinase C-selective and also has anti-estrogen effects. Thus, they said, they could not clearly exclude the potential contributory effect of estrogen receptor blockade.
The preliminary results of this pilot study need to be interpreted with caution, Dr. Zarate said. First, the group size was small, although the results were sufficiently positive to suggest pursuing larger controlled trials with protein kinase inhibitors in mania.
Second, the results may not be generalizable to patients with certain characteristics, for example, those with current substance abuse disorders. Finally, he said, these results may not apply beyond the acute treatment phase of bipolar mania.
The findings of this pilot study suggest that protein kinase inhibition might be relevant to the anti-manic effects of lithium(Drug information on lithium) and valproate(Drug information on valproate). Large controlled studies with selective protein kinase C inhibitors in acute bipolar mania are warranted, the researchers said.