Rifampicin is predicted to decrease
aripiprazole and quetiapine levels. An isolated report describes a marked fall in the
serum levels of a patient taking
clozapine when he was given
rifampicin. Haloperidol levels appear to be decreased by
rifampicin.
Be alert for the need to use an increased dosage of these
antipsychotics in the presence of
rifampicin. The manufacturers recommend that the dose of
aripiprazole should be doubled.