The Hospice Clinician Blog

The state of Washington will soon issue an unprecedented public health advisory that highlights the risks of methadone. This warning has been approved and adopted by a committee of state-appointed medical experts following an investigative newspaper story in the Seattle Times (see link below) which captured the attention of the state legislature. The Times claims that a review of death certificates in the state over the past 8 years  turned up 443 cases in which methadone was listed as the sole drug in fatal overdose cases (about 55 cases per year).  In addition the newspaper story states that methadone may have somehow been linked to over 2,100 fatal drug over-doses in that same 8 year period from 2003 to 2011. The Times story indicated that Washington's methadone death rate ranks among the country's highest. The story did not specify how many of these fatal overdose cases were situations where the individual was abusing the drug or if they were all patients with a legitimate prescription for the medication.  

The health advisory will stress that methadone can be more unpredictable than other analgesics, including other opioids. It will be sent to pharmacies as well as licensed health care professionals throughout the state.  

Methadone is unique in a number of areas when compared to other opioids. The unique differences offer very significant benefits as well as challenges to managing toxicity risk. If Washington’s efforts result in an increased awareness among physicians, nurses, and pharmacists of these issues leading to more appropriate methadone prescribing and follow-up, then this public health advisory can be the start of something quite  positive.  On the other hand, if the state’s initiative is designed to label methadone as a medication that is too dangerous to use in patients with severe chronic pain, then everyone in the state loses.  

Methadone has a bi-phasic nature when it comes to duration of analgesic effect. When methadone is initiated ,the duration of analgesic effect is about 4 to 6 hours at the most.   After continuous routine use for about five days, the drug exerts a more long-acting duration of approximately 12 hours in a majority of patients. The reason behind this is the fact that methadone is both highly lipid soluble and has a very large volume of distribution in the body.   These characteristics result in the drug accumulating in the body (upon continued use) and forming a kind of depot that creates the long-duration of analgesia, which is not seen during the initial few days of therapy. This is very different from other opioids. This concept must be understood and incorporated into the prescribing and monitoring practices whenever methadone is used.

There is also a wider degree of inter-patient variation in response to methadone than may be seen with some other opioids. Some patients may reach the “depot” stage with only 3 days of methadone dosing , while others may take 7 or 8 days. Attentive monitoring of the patient during this accumulation phase is essential. There will also be varying levels of cross-tolerance exhibited when converting from other opioids to methadone. This level of cross-tolerance will vary depending upon the dose of the opioid that one will be converting from. Generally, the higher the dose of opioid, the less cross-tolerance to methadone will be encountered. The practitioner should generally use lower equivalent dosages of methadone for patients on higher doses of other opioids to avoid inadvertent over dosage.  Successful methadone dosing may be challenging, however, methadone has been used extensively with very high success rates in numerous palliative care and hospice settings over the past decade.    It may be that practitioners in these settings have more experience and a greater appreciation for the unique pharmacokinetics of the drug than some others practicing in the general community.

The advantages of methadone are widely recognized and include the following:

• Effective where other opioids fail, such as in neuropathic pain
• Available in a variety of dosage-forms  that allow for administration to patients with swallowing difficulties (tablets that may be crushed, oral concentrate solution 10mg/ml)
• Methadone is absorbed well by the sublingual route (for patients that can’t swallow at all)
• The solution form is long-acting just like the tablets
• Very low cost.     Methadone is about  1/20 to 1/40  the cost of other long-acting opioids

The risks for methadone toxicity due to unexpected drug accumulation or incorrect conversion doses can be managed effectively when the practitioners understand the unique pharmacodynamics of methadone and follow appropriate prescribing and monitoring practices. 

The current issue with methadone toxicity addressed in the Times article and subsequently discussed within the Washington state legislature may boil down to a lack of education regarding this unique drug.  Physicians, nurses, and pharmacists all need to have a clear understanding of methadone pharmacokinetics before prescribing, dispensing, or caring for a patient on methadone.  This drug offers significant therapeutic benefits and unparalleled value over other long-acting strong opioids.  It would be very unfortunate if the actions of Washington state result in the denial of methadone availability for the patients suffering from severe chronic pain. On the other hand, this represents a great opportunity to promote and disseminate appropriate information to a wide range of health-care professionals regarding the effective use of methadone for those with chronic severe pain.  

See the Original Article on Methadone in The Seattle Times

Outcome Resources offers all of our hospice clients education and consultations to assist with the effective and safe use of methadone for their hospice patients. If you are interested in learning more about how we help hospices succeed, Contact Us.

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