Distribution methadone

The penalties for illegally using and distributing methadone are severe. Methadone is classified as a Schedule II substance. For illegal possession of methadone, the penalty (for first offenders) for possession of greater than 100 g is a fine of not more than four million dollars. The penalty for a second offense is a fine of no more than eight million dollars. 

Begg, E.J., T. J. Malpas, L.P. Hackett, and K.F. Ilett, Distribution of R- and S-methadone into human milk during multiple, medium to high oral dosing, Br. J. Clin. Pharmacol., 52(6), 681-685, 2001. 

Ultrafiltration has been used to determine the protein bound fraction of many drags, such as methadone (Wilkins et al. 1997), phenylacetate and phenylbu-tyrate (Boudoulas et al. 1996), etoposide (Robieux et al. 1997), doxorubicin and vincristine (Mayer and St-Onge 1995), disopyramide (Echize et al. 1995), and ketamine and its active metabolites (Hijazi and Boulieu 2002). Schumacher et al. (2000) have shown the applicability for the determination of erythro-cyte/plasma distribution. The method of UF has been applied in the measurement of free unaltered thyroxin or after displacement by salicylate as well after displacement by heparin in healthy people and in patients with non-thyroidal somatic illness (Faber et al. 1993). The protein binding of tritium labeled, antidiabetic repaglinide and its displacement by warfarin, furosemide, tolbutamide, diazepam, glibenclamide and nicardipine were determined by ultrafiltration (Plumetal. 2000). 

In overdose, methadone causes CNS and respiratory depression, miosis, bradycardia, hypotension, circulatory collapse, hypothermia, coma, seizures, and pulmonary edema (although less frequently than morphine). Treatment for methadone overdose includes supportive measures to maintain adequate respiration and blood pressure, and the administration of the opioid antagonist naloxone to reverse the effects of methadone. If repeated administration of naloxone is required, patients should be monitored for 48 to 72 hours following overdose. Dialysis is not an effective treatment modality, because methadone has a large volume of distribution (Vj = 4 to 5 L/kg) and is highly protein bound (87%). ... 

Typically, opioid dependency is treated initially with detoxification, usually as an inpatient. Except in a few individuals who remain drug free, detoxification is followed by long-term maintenance therapy. In the pasL opioid-dependent patients relied on methadone or levomethadyl acetate, but federal restrictions limited distribution of these drugs to a small number of methadone clinics, which are not only inconvenient, but also expose patients to other drug users, and can stigmatize patients if friends, family, or coworkers are aware of their trips to the clinic. There were limited provisions for take-at-home dosing of methadone or levomethadyl because of concern about the diversion of these drugs to illicit use. 

B. Pharmacokinetics. Usually, peak effects occur within 2-3 hours, but absorption may be slowed by their pharmacologic effects on gastrointestinal motility. Most drugs have large volumes of distribution (3-5 Ukg). The rate of elimination is highly variable, from 1-2 hours for fentanyl derivatives versus 15-30 hours tor methadone. See also Tables 11-43 and 11-59. 

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