What are you hoping to get out of asking this question? It sounds like you already know the answer.

I don't know, that's why I'm asking! If I'm in that situation I hope this option is available to me, and want to know what to ask for.

If the answer is that it's illegal I'd know I can't ask this directly/explicitly (but maybe there's a "secret handshake" way of asking for it). If it is I'd know I can. I wish no harm to OP.

See https://news.ycombinator.com/item?id=48878167

IANAD but have paid close attention to this for the same reasons. When my time comes I plan to let them know I'm in serious pain and prefer pain relief to life extension (though maybe in a more subtle way). I expect most will understand that.

I believe it varies by state but typically must be administered by a doctor or hospice nurse.

The patient must be hospitalised and the administration is justified as an analgesic, sedative and for heart failure when pressure, pulse and breath start to reduce. I believe any doctor whould agree after discussion with the relatives. The problem is the doctors rarely bring it to surface and the people don't know to demand it.

Thank you for the through answer! I hope I remember what to ask if/when the time ever comes.

Causing death in the course of administering treatment is not illegal.

For someone in severe pain, it’s completely legal to offering increasing doses of morphine to treat pain even if it results in death.