I can't speak knowledgeably about the postwar period, but it was definitely well-known and widely used in the US in the prewar period:

The United States, between 1885 and 1900, quickly took the stage as one of the leading consumers, producers, and promoters of early cocaine, for medical as well as popular usage.

from Gootenberg, Paul. Cocaine : Global Histories. Florence, KY, USA: Routledge, 1999.

Cole Porter also had a verse about cocaine in the original 1932 version of "I Get a Kick Out of You", suggesting its use as a party drug in high society, but I don't have an academic source for that at hand.

Between 1885 and 1903, Coca Cola had 9 miligrams of cocaine in each seven ounce serving. . The local drug stores in that period also sold products with a more potent dose of cocaine, for products like head ache powder and tooth pain medicine. Cocaine was outlawed before marijuana in the United States, but it was sold as an over the counter drug between 1885 and 1915.
Source: "The Cola Wars" by Jill Chen Louis 1980.