Taken from
Morphine Mega Thread & FAQ'S
Routes of Administration Bio-Availability
Oral - BA = ~30%
Insufflation - BA - ~30%
Plugging - BA = ~30%+
IM - BA = ~85-100%
IV - BA = 100%
Oral imho from experience & from reading various articles is preferable to nasal in most cases.
In the case of Extended Release Morphine preparations specifically oral is almost always a better choice than nasal.
Plugging from anecdotal evidence appears to beat oral & also beats nasal as such.
IV obviously is tops. (My ROA of choice; Obligatory warning- If you don't already use it, don't start, not worth it)
If for some reason someone does choose to use the nasal ROA mixing with chitosan can increase B/A.
Information regarding the ratio's can be found via a search.
So that answers your question & for future readers of the thread I'll sum up the B/A of Morphine.
The B/A of various ROA's for Morphine is as follows for clarity.
IV > IM > Plugged > Oral > Nasal
Note that if you choose to IV morphine & it is in pill form please use a
micron filter!