Haloperidol second-generation effects

TABLE 34-4. Comparative Side Effects among the Second-Generation Antipsychotics and Haloperidol... 

A mutual increase in serum levels of both thioridazine and paroxetine is evident when these agents are combined. Paroxetine has also been shown to increase haloperidol and perphenazine serum levels, with associated extrapyramidal side-effects. The mechanism is presumably via inhibition of hepatic enzymes. With respect to the second-generation antipsychotic drugs (SCAs), paroxetine at a dose of 20 mg/daily produces a 3-9-fold elevation in plasma risperidone. If paroxetine is administered with clozapine, mean plasma concentrations of clozapine and norclozapine may increase significantly (by about 30%). 

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