Opiate Bioavailabilities

[Forthesevenlakes]

The bioavailability of a drug is the percentage of the drug that makes it from the route of administration into the bloodstream. Intravenous administration of a drug means that all of the drug is put directly into the blood, so the bioavailibility of IV is always 100%. With other routes (oral, insufflated/snorting, rectal, etc.), less of the drug reaches the blood due to incomplete absorption, metabolism in the liver before reaching the blood, etc. By knowing the route of administration swiy plans to use for a drug, and its dosage, swiy can estimate about how much of it will make it into the blood, and thus be available for the brain.

This thread will be a place to post bioavailabilities of opiates through different routes. Please cite sources when you contribute to this thread, and as I re-find the sources I used to make this I'll add them as links to the percentages!

Buprenorphine
Oral: 15%
Sublingual: 30%-50%
Intramuscular: 68%

Codeine
Oral: 60-90%
Rectal: about 90%

Dihydrocodeine
Oral: 20%

Fentanyl
Oral: 30%
Buccal: 50% (absorbed through the mouth lining, not swallowed)
Transdermal: 92%

Heroin
Oral: 35%
Smoked: 52%
Intramuscular: 85%

Hydrocodone
Oral: 50-60%

Hydromorphone
Oral: around 51.35%, some reports say 10-65% but this range is awfully wide.
Intranasal: 54.4%
Rectal: 36.33, up to 60% in the source I used.

Meperidine
Oral: 50-55%
Rectal: 55%
Intramuscular: 80-85%

Methadone
Oral: 70%-80%

Morphine
Oral: 40%
Insufflated: 10% alone, 60% with a chitosan solution. But SWIM thinks this number should be higher. Can anyone find any articles that give alternative measures?
Intramuscular: 70-70% estimated
Rectal: 70-90% One study says 27% in a parental solution, however!
Subcutaneous: 60%

Oxycodone
Oral: 60-87% (due to low first-pass metabolism).
Insufflated: One study says 45%. However anecdotal evidence says that it may be higher than this number.
Rectal: 61.6% in one study.

Oxymorphone
Oral: 10-20%
Insufflated: ~40%

Pentazocine
Oral: 20%

Propoxyphene
Oral: 30-70% (This is quite a wide range. SWIM suspects its closer to 30% but has no other sources at the moment to confirm this.)

Tramadol
Oral:70%

more to come later, please contribute if you have any info! Also keep in mind that everyone's body is different, and may metabolize and absorb drugs in different ways. These numbers are averages, so your milage may vary.

Reputation Comments on this post:

	very important points, well-researched
	Thanks for putting this together, albeit several years ago ;)
	Good topic to start a thread on
	very useful, stimulated good discussion