My cousin is taking 4.5 mg of rivastigmine in the morn for dementia. at night he takes 50 mg quetiapine for schizophrenia which causes disorientation?

Don't understand: I'm sorry but please reread your statement. I'm not understanding exactly what you'd like to ask. It is common to prescribe quetiapine together with rivastigmine for hallucinations. You certain it's being given for SCHIZOPHRENIA? I'm not a great fan of quetiapine in the demented elderly as it can cause excessive drowsiness & confusion. Ask the doctor for clarifications and possible alternatives.

The dementia: Rivastigmine provides limited benefit for dementia (no real effective treatment ) and quetiapine (Seroquel) is use for agitation and insomnia associated with dementia. Neither prevent the progression of the disease (although rivastigmine may slow for about 6-12 months). Disorientation in dementia can be caused by other meds, sleep apnea, urinary tract infection, any other medical illness etc.

Comment: Not knowing particulars, can only partially comment. The rivastigmine dose is sub therapeutic, and to be most effective, dose will need to be raised. The quetiapine may need dose modification also. The involved doctors should reassess this.