From: susremischsp@mtiamec.gnoaheetad (Samson) Subject: Oral heroin absorption Date: 1997/09/26 Newsgroups: alt.drugs.hard This study compared sublingual absorbtion of various opiates. It found heroin slightly (but not significantly) better absorbed than morphine. Sublingual absorption is a different mechanism from GI, though, since the mouth is much more basic than the stomach (duh). So this doesn't decide the matter. (Another article, Med Clin North Am, 1987;71:207-232, gives IM/PO analgesia ratios of 6:1 for morphine and 6-10:1 for heroin. With the given 1:2 ratio of equianalgesic IM dose of morphine:heroin, this would make heroin 1.2 to 2 times as potent as morphine when taken orally. Not much detail in that article.) Title Sublingual absorption of selected opioid analgesics. Author Weinberg DS; Inturrisi CE; Reidenberg B; Moulin DE; Nip TJ; Wallenstein S; Houde RW; Foley KM Address Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY. Source Clin Pharmacol Ther, 1988 Sep, 44:3, 335-42 Abstract Ongoing interest in the improvement of pain management with opioid analgesics had led to the investigation of sublingual opioid absorption. The present report determined the percent absorption of selected opioid analgesics from the oral cavity of normal subjects under conditions of controlled pH and swallowing when a 1.0 ml aliquot of the test drug was placed under the tongue for a 10-minute period. Compared with morphine sulfate at pH 6.5 (18% absorption), buprenorphine (55%), fentanyl (51%), and methadone (34%) were absorbed to a significantly greater extent (p less than 0.05), whereas levorphanol, hydromorphone, oxycodone, heroin, and the opioid antagonist naloxone were not. Overall, lipophilic drugs were better absorbed than were hydrophilic drugs. Plasma morphine concentration-time profiles indicate that the apparent sublingual bioavailability of morphine is only 9.0% +/- 11.9% (SD) of that after intramuscular administration. In the same subjects the estimated sublingual absorption was 22.4% +/- 9.2% (SD), indicating that the sublingual absorption method may overestimate apparent bioavailability. When the oral cavity was buffered to pH 8.5, methadone absorption was increased to 75%. Thus, an alkaline pH microenvironment that favors the unionized fraction of opioids increased sublingual drug absorption. Although absorption was found to be independent of drug concentration, it was contact time dependent for methadone and fentanyl but not for buprenorphine. These results indicate that although the sublingual absorption and apparent sublingual bioavailability of morphine are poor, the sublingual absorption of methadone, fentanyl, and buprenorphine under controlled conditions is relatively high. Language of Publication English Unique Identifier 88328266 __ remove 'sure, sp@m me, go ahead', to reveal a valid email address. it won't be easy. get to work.