I have some difficult-to-treat medical issues and about 1/3 of the handful of pills I take every day are off-label. I think when you get into less common medical concerns off-label use becomes much, much more frequent.

E.g. gabapentin is an anti-seizure medication that has been found to reduce neuropathic pain as well. It has shot up to the 5th most prescribed medication in the last decade as it has replaced long-term opioid use for new chronic neuropathic pain patients. This is 100% off-label and is prescribed by everyone from NPs all the way up to neurosurgeons for this purpose.

I’ve never been asked to sign a waiver and I can’t imagine that for-profit hospitals would allow their doctors to prescribe off-label medications willy-nilly if they represented big liability. (I don’t know this for sure, this is just what my experience implies.)

Yup, I've seen this sort of off label prescription at least 3 times.

A lot of drugs require almost no evidence (especially if they are relatively cheap or common) to be given to the insurance company when they are prescribed. And if you are willing to pay for it, you can always pay out of pocket if insurance is being a pain.

> I’ve never been asked to sign a waiver

That presumably has to do with the risk profile of the medications you've taken. If there was a high risk of devastating side effects and it was off label presumably the prescriber wouldn't be willing to take on the liability.

Do you know that for a fact or are you just guessing?

I would wager if those waivers actually did anything they'd boilerplate a generic version of it in the legal mumbo jumbo you have to sign even if you come in to have the doctor look at a stubbed toe.