[Chad C. Mulligan]

In the USA it's mostly used for livestock. In Africa it's very widely used to treat "river blindness", an endemic parasitic disease.

The only problem in the USA is that too many doctors won't prescribe it, so desperate sufferers go off and use livestock preparations at the wrong dosages.

The Hippocratic oath starts with "First, do no harm". Willfully withholding an effective treatment strikes me as deliberate harm!

How do they live with themselves?

[TChad]

The Hippocratic oath starts with "First, do no harm".

While that is widely believed, it is not true.

https://www.thoughtco.com/first-do-no-harm-hippocratic-oath-118780

Also, modern American physicians are not required to swear to abide by the Hippocratic Oath, at least not to the ridiculously outdated original Greek oath.