why do people with extreme pains that take Opioids don’t feel euphoria as would a normal person feel if they took Opioid ?

Question

I’m learning pharmacology for my exam and found this in my book and its written that its not known why.

In: Biology

Answer 1

A person who is “opioid naive” (hasn’t had opioids before or recently) is going to be way more sensitive. The more you take opioids, the more your body gets used to them, because they are stronger than what your body normally produces. Your opioid receptors get used to having that strong drug sitting on them, activating them at a high level. Your body even comes to depend on the drugs to feel “normal”, so you require higher and higher doses to relieve pain. Eventually you’re not chasing a high so much as avoiding withdrawal.