Posted by ed_uk on October 28, 2005, at 17:19:18
In reply to Re: meds for psychotic depression » ed_uk, posted by SLS on October 28, 2005, at 16:55:23
Hi Scott,
Although haloperidol has acquired an particularly unpleasant and disturbing reputation (partly thanks to ER), it really isn't any worse than any of the other high-potency APs....... which perhaps isn't saying much. Nevertheless, it can be useful for some people. It does have the advantage of being a more thoroughly studied drug than any of the other typical neuroleptics.
>Thorazine was not gentle with me - immediate orofacial dyskinesia. Prolixin was better.
I expect it was a matter of dose. At an 'equivalent' antipsychotic dose, chlorpromazine is (apparantly) less likely than fluphenazine to cause a dystonic reaction. As I have discovered myself, the effects of typical neuroleptics are VERY dose-dependent. I was able to tolerate a low dose of chlorpromazine (25mg) reasonably well whereas a high dose caused intense dysphoria and akathisia. 25mg chlorpromazine caused no akathisia whatsoever, although it did make me cognitively impaired!
The exceptional potency of haloperidol (as a D2 antagonist) is illustrated by the following study.......
OBJECTIVE: The authors tested the hypothesis that a dopamine D(2) receptor occupancy level between 60% and 70% in patients with recent-onset schizophrenia would result in optimal subjective experience. In addition, they sought preliminary evidence on whether subjective experience is better with low-dose olanzapine than with low-dose haloperidol. METHOD: Subjects (N=24) who met DSM-IV criteria for schizophrenia were randomly assigned to 6 weeks of double-blind treatment with either olanzapine, 7.5 mg/day, or haloperidol, 2.5 mg/day. Subjective experience, psychopathology, and extrapyramidal symptoms were assessed at baseline and at endpoint. After 6 weeks, D(2) receptor occupancy was assessed with [(123)I]iodobenzamide single photon emission computed tomography. RESULTS: The two study groups were similar at baseline. After 6 weeks, patients receiving olanzapine had a significantly lower mean dopamine D(2) receptor occupancy (51.0%, range=36%-67%) than those given haloperidol (65.5%, range=45%-75%). Receptor occupancy between 60% and 70% was associated with optimal subjective experience, and subjective experience improved significantly in the haloperidol group. CONCLUSIONS: A level of D(2) receptor occupancy between 60% and 70% is optimal for subjective experience of patients with recent-onset schizophrenia. Substantial interindividual variation in D(2) receptor occupancy was seen at fixed low-dose levels of olanzapine and haloperidol. Olanzapine, 7.5 mg/day, showed no superior subjective response over haloperidol, 2.5 mg/day. Olanzapine may need to be dosed higher than 7.5 mg/day for most patients with recent-onset schizophrenia, and haloperidol needs to be individually titrated in the very low dose range to reach optimal occupancy.
~Ed
poster:ed_uk
thread:572602
URL: http://www.dr-bob.org/babble/20051024/msgs/572783.html