Heroin is a brand name invented by Bayer for diacetylmorphine that was marketed throughout the Western world as a potent cough suppressant. Even though an opiate epidemic was raging in the United States when heroin was introduced it never really caught on as a prescription medication.

Quoting https://www.reddit.com/user/BedsideRounds/From Redditt https://www.reddit.com/r/medicine/comments/750fcm/an_advertisement_for_bayer_from_the_early_1900s

Heroin was developed as a cure for morphine addiction. What it's developer, an English chemist, didn’t realize or intend was that heroin is more addictive than morphine. It was marketed by Bayer, which lost the trademark in 1919. Bayer marketed it as a non-addictive alternative to morphine and as a cough suppressant.

Quoting Melina Druga https://www.melinadruga.com/the-soldiers-disease/