the results obtained in studies on 1 , 9 , and 18-month-old sprague-dawley rats and on 7 , 16 , and 24-month-old fischer-344 rats showed that phenobarbital concentrations at the pharmacologic end-point decreased with increasing age , indicative of an increased sensitivity of older animals to the cns depressant effect of the barbiturate .
C0031412
phenobarbital
C0004745
barbiturate