How toxic are opiates and opioids for the organs and how harmful are these substances for the psyche?

They have a strong potential for addiction, and you can overdose on them. I'm aware of other side effects like constipation.

In this Wikipedia article on pharmacology, for example, it says that heroin is not toxic to the organs. I once watched a video about consumption rooms. And it also said that heroin is not toxic to the organs. And that these heroin addicts can live to a very old age even though they inject heroin every day.

https://de.m.wikipedia.org/wiki/Heroin

That's why I wanted to ask how toxic these substances are in their pure form, without any cutting agents.