Which preposition to use with soporific

in Occurrences 4%

But for Heaven's sake, young Sangrado, be a little more sparing of extenuatives and soporifics in your practice than you have been in your poetry.' Even the death of Keats, in 1821, did not abate the rancour of Blackwood's Magazine.

on Occurrences 1%

At length the eldest of them broke silence, by inquiring of his next neighbour, "Hast thee heard how indigos go at the India House?" and the question operated as a soporific on my moral feeling as far as Exeter.

Which preposition to use with  soporific