[refurb]

The therapeutic index of opiates narrows continuously as addiction proceeds.

Whoa there. That's not correct. As you develop tolerance to the "high" you also develop tolerance to the side-effects, namely respiratory depression (what usually kills you during an overdose).[1]

"Tolerance to the analgesic effect of opioids can begin after a few weeks of around-the-clock dosing, as does tolerance to the respiratory depression effect of opioids (and other side effects except constipation)."

The paper I reference has a great example of just how much morphine you can give to someone in pain:

"The final dose escalation was to 1,100 mg/hour of morphine IV plus 100 mg IV every 10 minutes as needed. MK lived 3 days on this morphine dose. He was somnolent his last day, but he could be aroused to take fluids with gentle verbal stimulation."[1]

Just to provide some context, if you were to break your leg and go to the hospital, they'd probably give you 10 mg of morphine IV every 4-6 hours. This guy was on 1,100 mg every hour around the clock.

[1]http://www.promotingexcellence.org/downloads/jacs_0203.pdf

[hapless]

The therapeutic index is the ratio between the necessary dose to achieve desired effects, and the dose that incurs dangerous side effects. Both doses rise with tolerance, but the ratio between them narrows.

That opiate-tolerant fellow on 1,100mg/hr of morphine required around-the-clock monitoring by experts.