Chronic oral haloperidol and clozapine in rats: A behavioral evaluation

The present study evaluated chronic oral treatment of rats with haloperidol or clozapine, Drugs were given in the drinking water for a 23-day period. Rat behavior was analyzed once a week in an open field. Rats ingested eithe r 1.7 mg/kg haloperidol or 40 mg/kg clozapine daily. Blood serum analysis r evealed concentrations of 6 ng/ml for haloperidol and 22 ng/ml for clozapin e at the end of the treatment. Haloperidol decreased overall activity from the onset of treatment. Clozapine showed similar effects only on the last t est day. Control animals showed a slight habituation in exploration-related parameters. In conclusion, these results indicate that oral drug administr ation through the drinking water is a suitable mode of noninvasive chronic treatment that led to sufficiently high drug levels to induce specific phar macological effects in rats.