How do roxycodone and methadone interact if taken together?

Question

Does the methadone effect the strength of the roxycodone when taken together?

Answer 1

Roxycodone is a pure opiate whereas methadone is a partial opiate agonist and partial antagonist, meaning that in some ways it acts as an opiate and in other ways it counteracts the effects of opiates.

The effects and side effects that methadone has in common with typical opiates like roxycodone include the following: analgesic and antitussive properties, respiratory depression, sedation, decrease in bowel motility, increase in biliary tone, hormone regulation and increase of prolactin and growth hormone release, miotic pupils, nausea, and hypotension. Some of these effects, like respiratory depression (breathing problems), are dangerous and can lead to death in the event of overdose. Therefore methadone can worsen some of the dangerous side effects of roxycodone and vice versa. These drugs should not be taken together -- except perhaps under a very close supervision of qualified medical professionals.

Answer 2

The poster who answered said "methadone is a partial opiate agonist and partial antagonist, meaning that in some ways it acts as an opiate and in other ways it counteracts the effects of opiates. "

This is completely incorrect!! Methadone is a 100% opioid, MU receptor agonist. It has ZERO antagonist properties at the opiate receptor.  It doesn't help anyone posting misinformation.  Sorry to get up in arms, but this is the third post I've read on this site that contains some type of totally wrong information. How is that helpful? Maybe people should check their information before they post it!

The type of methadone used in most countries does however, have antagonist properties at the NMDA receptor.
Most countries use the DL type of methadone. This molecule basically has a mirror image of itself. A left side and right side. The dextro side of the molecule has no opioid properties at all. It has NMDA receptor antagonist properties. It is the levo side of the molecule that is an opioid agonist.

In Germany they use methadone that only contains the L side of the molecule.

If taken with Roxicodone,  what would occur depends on a few things. The dosage of methadone, and how long you've been on that dosage. If you're on 40mg or less, of methadone and you add Roxicodone,  both being opioids, they'd just add to each others effect. Similar to drinking a glass of scotch after a glass of vodka.  As the other poster correctly pointed out, this could be dangerous though and should only be done by a doctor very experienced with methadone and only with a patient sufficiently opioid tolerant.
Methadone, at a sufficient dosage, can have what is referred to as a blocking effect. (maybe this is what the other poster was referring to?) So, *at sufficient dosage* it blocks any euphoria from other opiates, but not because it's an antagonist. ( This so called blocking effect usually occurs at dosages of 60 to 80mg and above and those dosages are usually only used on opiate addicts who are very tolerant to opiates. Such dosages would likely be lethal to someone not sufficiently tolerant to opiates )  So this blocking effect has more to do with the size of the molecule itself, rather than any antagonist effect, but I won't get into that.
   Taking both at the same time could also cause overdose and death if you take more than prescribed, or don't have sufficient tolerance to take them both together. Could be a dangerous combination. Methadone can be unpredictable in patients that aren't sufficiently opiate tolerant