Which preposition to use with sedative

to Occurrences 2%

It has been shown that lime is, relatively, a sedative to cells.

as Occurrences 1%

And in respect to yet more perilous sensual excesses, tobacco is now admitted, both by friends and foes, to be quite as much a sedative as a stimulant.

at Occurrences 1%

Milk is, in fact, a nutrient and a sedative at once.

for Occurrences 1%

Attributing her condition to a nervous attack, he gave her some medicine, took her to the drawing-room, and prescribed the new piano, which he had already found the best of all sedatives for her.

than Occurrences 1%

Tobacco may more properly be called a sedative than a narcotic.

Which preposition to use with  sedative