when it contains marijuana, its never "safe"
Marijuana is usually safe to mix with other drugs, if you are experienced with both.
Methadone is synthetic and quite harmful and highly addictive. Codeine and morphine are both natural - made from poppy extract. Of course, cyanide is also natural. 'Natural' does not mean 'safe'. Morphine is 10 times stronger than codeine. Morphine and methadone are highly addictive, while codeine only moderately.
It takes away the potency of the codeine! In other words the codeine is weakened by the mixture of THC
You're free to mix anything you want to mix, any time you want to mix it. But that doesn't necessarily mean that it would never be a foolish thing to do, or that it would never hurt you, make you sick, or kill you.
SURE!
yes
You can mix marijuana with most every drug. In fact, I do not know of any medications/drugs that are dangerous to take with marijuana.
yes yes
Mixing them is as safe as taking the ecstasy in itself. Cannabis never potentiates anything (mental potentiation aside). It's really a great combo. Have fun!
no it is not safe
I don't see a problem with this. The pot might actually combat the nausea usually aquired by the codeine. Pot is safe in combination with a lot of psycoactive drugs.
Yes