Posted by med_empowered on December 1, 2005, at 19:01:22
In reply to Re: zyprexa: 5mg, dopamine blocked?, posted by Tomatheus on December 1, 2005, at 15:58:10
hi! I also can't tell you exactly how much D2 blockage to expect. However, one interesting thing about antipsychotics is the *huge* variation from individual to individual. 5mgs/Zyprexa may have 70% or so D2 ocoupancy in some people with first-epsidoe psychosis (apparently, at around 70%, the D2 blockade is sufficient for antipsychotic use; at around 80%, EPS starts to pop up). However, other individuals may not get this sort of symptom-control until they reach 15-20+mgs/day. As an example...a BP I friend of mine takes Symbyax (the zyprexa plus prozac combo) as his primary treatment. He takes the 12/50 caps, which is 12mgs zyprexa, 50mgs prozac. He's had great results and few side effects. When I tried 2.5mgs/day zyprexa--one half of a 5mgs tab--I developed pronounced akakthisia.
Are you starting out on 5mgs/zyprexa? For depression, that strikes me as a bit high. Personally, I'd use a pill cutter to chop the pills in half (or fourths, if you'd prefer) and then adjust the zyprexa dose in small increments until you feel better, but still have minimal side effects. Also, some people dont take the antipsychotic during the entire treatment period...in years past, when the older antipsychotics were used to augment antidepressants (ex: perphenazine), it was pretty common for a patient to take a low-dose of the antipsychotic for a week or two, and then discontinue it once the symptoms of depression had improved. I think that's probably a strategy worth re-visiting with today's antipsychotics.
Anyway, as the other poster mentioned, part of the rationale of the antipsychotic augmentation seems to be that there can actually be an *increase* in levels of certain key neurotransmitters, rather than a decrease. This is definitely the case with Symbyax; the levels of dopamine, serotonin, and norepinephrine were all increased significantly while on Symbyax, much more so than with treatment with either Prozac alone or Zyprexa alone.
poster:med_empowered
thread:584237
URL: http://www.dr-bob.org/babble/20051126/msgs/584306.html