A lot of those stories don't involve alcohol. Opioids and benzodiazepines kill so many people, and regular mixing of CNS depressants leads to a possibly fatal drug induced false sense of security.
The Opioid Equivalency chart can be found in my signature, please factor in that you have Mallinckrodt Morphine Sulphate Extended Release Tablets, so it will release 60mg over 12 hours.
Bioavailability is the percentage of drug that is actually absorbed into the bloodstream via any given ROA, or Route of Admninistration, which includes routes like oral, rectal, nasal, intravenous, intramuscular, sub cutaneous, inhalation (vaporization), etc.
Some drugs are better absorbed orally than others. Oxycodone has a bioavailability of about 87% taken orally, while morphine taps out around 30% ish. What this all means is, say you take 10mg oxycodone orally, just for simple math purposes, at the very most 8.7mg of oxycodone will get into your bloodstream out of the 10mg you dosed. This is NOT factoring in first-pass metabolism, which is a natural defense mechanism of your body. Taken orally, the drug goes through your liver before hitting the bloodstream. With morphine, the first pass metabolism is very high, I forget the exact percentage but it's significant, so only a fraction of the morphine you consume orally actually hits the bloodstream.
However, when administered via IV or rectally for example, you bypass your bodys natural defense mechanism, evading first pass metabolism, but you still have to factor in the BA of these different ROAs. IV's BA is of course 100%, and rectal BA varies considerably, usually from 30-60%, meaning you can potentially double the amount of morphine that hits your bloodstream by taking morphine rectally (up to 60% BA, drug bypasses liver and first pass metabolism) than you do taking it orally (usually ~30% AND first pass metabolism). Therefore it makes sense that some people want to get more out of the same amount of drugs, and if you're like me and do not IV anymore, rectal morphine is the next best thing. For a drug like morphine, you can double the amount of drug that hits your bloodstream, which is why people choose not to take it orally.
However, a drug like oxycodone already has such a high oral bioavailability that there's no need to take it via other ROAs, although some people do as a matter of preference, because other ROAs have faster onsets. Some people like snorting oxycodone even though it's much less effective than oral dosing, only 67% is absorbed nasally, but the onset is faster which can create the illusion that snorting it is stronger, when in reality you're getting less drug, but in a shorter time span it feels like more.
I hope this helps explain the concept of bioavailability and routes of administration. Please take advantage of our search engine, this exact material has been covered hundreds if not thousands of times before and there's a lot to learn by typing in a few keywords to the search box at the top right hand corner of our forum.
