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ANTIPSYCHOTICS AND PHENOBARBITAL

Medical Diagnosis and Drugs, Medications
Haloperidol plasma levels, and possibly clozapine levels, are roughly halved by phenobarbital. Aripiprazole, chlorpromazine and possibly thioridazine levels are also reduced by phenobarbital. The plasma levels of quetiapine are predicted to be reduced by barbiturates.
Monitor concurrent use to ensure that the antipsychotics remain effective. The manufacturers of aripiprazole suggest doubling its dose. It is also important to consider the seizure potential when prescribing antipsychotic medications.
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