Zyprexa and Haldol?

  A developmentally disabled friend has been taking 30 mg./day of Haldol for
  several years to control aggressive behavior.  In September, he was prescribed 2.5 mg./day of zyprexa - the idea was to gradually eliminate the
  Haldol, because Zyprexa has fewer side effects.  On December 9, he began to slur his words, eyes were glassy, lost short term memory, and his walking became unstable.
  It became progressively worse, but his doctor kept sending him home to "wait and see."  On Dec. 22, the doctor cut off the Haldol.On Dec. 24, he could not walk, and his temp was 83 degress f!  His blood pressure also dipped very low.  He was rushed to the hospital, where they placed him on antibiotics and removed his blood, warmed it and replaced it.  He's much better now, however he is hallucinating and still has memory problems.  He is 55 years old.  The diagnosis:  sinus infection!? Another thing going on with him- he broke his hip a year ago, and it was recently discovered that the pin is loose and floating around inside.  They had surgery planned, but no one thinks an infection is caused by this.
  Can these dosages of Haldol and zyprexa be toxic in a man his age?  And what could have caused the low temp?
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Sounds like your friend has had numerous medical problems. The low temp and low blood pressure sound like sepsis, which is a dangerous condition when infections get out of hand. The doctors look for whatever could have started it, such as urinary tract, lungs, open wounds, sinuses, etc. Sinusitis is not an uncommon problem.
Sepsis can play havoc with one's mental status. I have seen more than one person with a normal cognitive function become completely delirious when challenged with sepsis. This can develop within hours.
I have never seen any medication (other than immunosupressants such as steroids or chemotherapy) make someone susceptible to sepsis. So the infection and the dopamine blocking agents are not related.
The susceptibility to side effects of Haldol and Zyprexa and related drugs(and for that matter, the basic effectiveness of the medication as well) is affected by the developing infection and ultimately the sepsis.
The residual cognitive effects of sepsis can take quite a while to resolve, especially in an individual whose cognitive compensatory mechanisms are challenged to begin with. It's not unusual to require short-term changes of medication doses with gradual return to a stable dose.
Your doctor may decide that in the long run that Zyprexa is OK to use, but for now no one is going to be able to fully evaluate Zyprexa versus Haldol in terms of how well it works until everything stabilizes.
I hope this helps. Of course, you know that this forum is strictly for educational benefit, not for actual medical advice. CCF MD mdf.