Foods and methadone

[GutterPhenomenon69]

Swim wonders something. Are their any foods or drinks that can interact with methadone. swim obviously knows that there are some medications that will but swim wants to know if there are any foods or drinks that might interfere at all.

[Gradient]

GutterPhenomenon69,

I am going to assume that your question regards potentiation/inhibition of opiate effects derived from dietary interactions. Swim hasn't read anything specific on the subject, but if memory serves, methadone is characterized by an alkaloid pH. This means that it must undergo metabolism in the stomach before the bulk of it is absorbed in the large intestine. To avoid ionization in stomach acid, swim would consume basic foods. However, swim also remembers that methadone is tremendously more bioavailable than most other opiate alkaloids. Perhaps ionization isn't much of a factor, and simply consuming the methadone on an empty stomach would expedite/intensify elicited effects. Swim found the following abstract on the subject:

U. Meresaar2, M. -I. Nilsson1, 3, J. Holmstrand1 and E. Änggård1, 4
The disposition of methadone was studied in eight opiate dependent subjects during detoxification. Plasma concentrations were determined by mass fragmentography for 48 hours after administration of methadone 20 mg as tablets and simultaneous intravenous injection of deuterium-labelled methadone 20 mg. Pharmacokinetic parameters were calculated for the intravenous dose assuming a two compartment open model. Bioavailability was determined by comparing the areas under the plasma concentration versus time curves of unlabelled and labelled methadone. The beta-phase plasma half-lives varied five-fold, with a range from 8.5 to 47 h. The apparent volumes of distribution varied from 2.1 to 5.61/kg. Five patients had a bioavailability exceeding 90%, and three had lower bioavailabilities of between 41 and 76%. The unlabelled and labelled drug appeared to be pharmacokinetically equivalent. The data show that for a majority of these subjects the bioavailability was higher than 45%, the previously reported value. The marked individual variation in methadone pharmacodynamics and kinetics, and the possibilities both of cellular and methabolic tolerance, require an individually optimized dosage regimen.

With such variability in the bioavailability in individuals with tolerances, swim wouldn't be surprised if enzymatic induction is responsible. The cytochrome enzymes in the liver likely account for such differences, and therefore likely present the best avenue for potentiation. Grapefruit juice should intensify effects nicely, though it sounds like swiy is familiar with other, better, agents (cimetidine comes to mind).