Thursday, July 9, 2009

Methadone on Methadone

Journal of Opioid Management has a tidy paper about using methadone as an analgesic for patients on methadone maintenance therapy (for heroin addiction).

The data come from a retrospective chart analysis of 53 HIV+ adults on methadone maintenance therapy who were treated in an HIV pain clinic over at least a year. (Note they only included patients who were seen in the clinic for a year, which likely pre-selects 'success' patients.) All patients were in a methadone maintenance program, and had additional analgesic doses of methadone added by the pain clinic (maintenance doses were kept the same). Patient's analgesia methadone was adjusted per routine practice at the clinic. About 44% of patients were being treated for painful peripheral neuropathies.

The mean maintenance dose was 100 mg a day. The mean starting analgesia dose of methadone that the clinic providers prescribed was 60 mg a day (divided per clinic practice tid or qid). At the end of 12 months the mean analgesia dose was ~200 mg a day. Mean pain score at the time of analgesia methadone initiation was 9/10 and was ~5/10 at 1 month and ~4/10 at 12 months (patients were also receiving other analgesics and adjuvants per routine clinic practice). The clinic did routine urine toxicology screens and about a quarter were positive for heroin (13% for heroin alone & 13% for heroin and cocaine) at 12 months (interesting; difficult to interpret without knowing what is expected/routine in MMPs). Side effects were generally acceptable.

This is by far the largest study that I know of about this topic, and while it is uncontrolled data it is still helpful in a few ways.

  1. Studies like this are sort of 'proof of principle' studies which underlie the idea that this practice can be done safely and effectively. Of course the patients were receiving other non-opioid analgesics, no controls, etc. etc. However, it suggests that in at least ideal circumstances (a presumably well put together pain clinic with competent providers) adding additional methadone as an analgesic to a patient's maintenance dose can be done safely and is ( the very least part of a treatment plan that is...) effective.
  2. So assuming that's helpful information this sort of data also gives those of us who sometimes do this some useful information about doses etc. This group used starting doses generally ~2/3 of the maintenance dose, and frequently titrated up slowly to doses over double the maintenance dose, seemingly with good outcomes.
  3. The authors note that in their experience patients without addiction problems routinely need methadone doses lower than these patients maintenance doses (ie less than 100 mg a day). Many of these MMP patients ended up on 300 mg a day of methadone in this program, giving further support to the widespread clinical observation that patients with addiction problems/histories generally require higher doses than those without.

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