Posted by med_empowered on October 27, 2005, at 7:57:15
In reply to Re: Any remedy for DA Receptors Tolerance?, posted by lunesta on October 26, 2005, at 21:23:06
hey! Neuroleptic supersensitivity is kind of under-reported, and not very openly discussed. Its most studied with the old drugs (especially haldol). Here's how it works: patient takes Haldol. Haldol "occupies" large # of D2 receptor (70-90+ percent). Since the brain is getting such a tiny amount of dopamine, it springs up new dopamine receptors to compensate. This is part of the reason why its common to see people with schizophrenia start on a small dose of antipsychotic--say, 3mgs Haldol, 5mgs Zyprexa, etc.--and gradually progress to higher and higher doses just to control the hallucinations, so they may be taking 10mgs haldol or 15mgs zyprexa in a couple years. The drug-induced changes in the brain can lead to "supersensitivity psychosis"; some patients, given Thorazine and other drugs for depression, bipolar, or other non-psychotic disorders became floridly psychotic upon withdrawal of the drug..the psychosis went away once the drug was re-instated. The theory is that the brain can become so sensitive to its own dopamine that withdrawal of the neuroleptic results in a dopamine-overload leading to psychosis. Some studies have found that if you add an anti-convulsant mood-stabilizer to an antipsychotic you can reduce the "kindling" effects of the drug on the brain and keep the doses minimal. From what I understand, Abilify doesn't seem to induce dopamine supersensitivity, at least not to a great extent; apparently, because the agonist/antagonist action at both dopamine and serotonin kind of creates a sort of equilibrium, there are minimal long-term changes to the brain. And even with older antipsychotics, low-doses can sometimes be activating (ex: amisulpride, flupenthixol) instead of sedating; the super-low dose can result in increased reaction time and reduced apathy, while upping the dose can result in the "10 yard stare", lethargy, apathy, and general "dullness" we all associated with antipsychotics. Good luck!
poster:med_empowered
thread:572106
URL: http://www.dr-bob.org/babble/20051024/msgs/572329.html