Q & A About Methadone
                  By Lynn R. Webster, MD, FACPM, FASAM 
                  Medical Director, Lifetree 
                  
                  Pain Clinic
                  Medical Director and CEO, Lifetree Clinical Research, 
                  
                  Salt Lake City, Utah 
Q. What are methadone's benefits and potential dangers?
                    Research demonstrates that methadone can be effective in 
                  
                  treating some forms of neuropathic pain but also requires 
                  
                  specific knowledge to use safely. Several states have recorded 
                  
                  increases in accidental overdose deaths, many of them involving 
                  
                  methadone. More research is needed into the exact reasons 
                  
                  for the deaths, but at last some contribution appears to be 
                  
                  tied to methadone prescribed for pain. There is difficulty 
                  
                  in analyzing methadone's distinct contribution because lethal 
                  
                  blood levels may vary depending on the decedent's degree of 
                  
                  opioid tolerance, the severity of chronic pain and the action 
                  
                  of polydrug combinations. Levels of methadone typically reported 
                  
                  as a cause of death may actually be therapeutic in some chronic 
                  
                  pain patients on long-term methadone therapy. Regardless, 
                  
                  methadone does present some unique pharmacologic properties 
                  
                  that need to be understood to utilize it safely. 
Q. What should a clinician know about methadone before 
                    
                    prescribing it for pain? (YES, pain, not "just" addiction, as if that is to be taken any more lightly!!!)
 
                    Pain experts typically administer opioids in the belief that 
                    
                    patients quickly develop near complete tolerance to respiratory 
                    
                    depression. Research is beginning to indicate that clinicians 
                    
                    may underestimate the risk of respiratory depression, particularly 
                    
                    in the initial conversion to methadone. Methadone is eliminated 
                    
                    from the body at a slower rate than many other opioids. Its 
                    
                    long, variable half-life averages around 48 hours but can 
                    
                    be up to 100 hours. Methadone's properties increase its potential 
                    
                    for polydrug interactions. 
Also, if patients defy medical 
                    
                    direction and escalate methadone doses in an attempt to control 
                    
                    their pain, the results can be lethal.
Q. What is methadone's relationship to sleep?
 
                    Methadone-related deaths may be influenced by a patient's 
                    
                    dosing schedule, including time of the last dose of the day 
                    
                    in relation to the onset of sleep. In particular, the presence 
                    
                    of sleep apnea appears to pose a risk: New research suggests 
                    
                    a relationship between doses of methadone and increased incidence 
                    
                    of sleep apnea, particularly in combination with benzodiazepines. 
                    
                    If patients are at risk for sleep apnea, clinicians are advised 
                    
                    to obtain a sleep study to determine whether patients require 
                    
                    supplemental oxygen, continuous positive airway pressure (CPAP) 
                    
                    or some other support to safely consume methadone for pain.
                      Q. What is the safe approach to an initial dose of methadone?
                      Clinicians are advised to start methadone therapy with a 
                    
                    low dose and titrate slowly to an analgesic effect. Published 
                    
                    conversion tables are inadequate in giving equianalgesic doses 
                    
                    of methadone compared to other opioids. Cross tolerance from 
                    
                    other opioids to methadone is incomplete, and the tables are 
                    
                    designed for a single dose, not for chronic administration. 
                    
                    The result may be a recommended starting dose that is too 
                    
                    high.
For now, safe practice supports starting methadone with a 
                    
                    ceiling dose of no more than 20 mg/day (10 mg/day for elderly 
                    
                    or infirm patients). Dose changes should not occur more often 
                    
                    than weekly to allow a steady state of methadone to develop 
                    
                    and for the peak side effects to become clear. For patients 
                    
                    who are being converted from another opioid to methadone, 
                    
                    clinicians should slowly titrate downward the other opioid 
                    
                    as they slowly titrate methadone upward. This practice will 
                    
                    minimize the risk of withdrawal and the risk of overdose involving 
                    
                    either methadone or a combination of the two opioids.
These guidelines represent a more conservative recommendation 
                    
                    than seen elsewhere. Certainly, some patients are able to 
                    
                    tolerate a much more rapid conversion or titration. Nevertheless, 
                    
                    given the reports of deaths associated with methadone, these 
                    
                    starting guidelines should help clinicians ensure patient 
                    
                    safety and give methadone pain therapy a greater chance of 
                    
                    success.
Q. How should patients be counseled?
 
                    Patient counseling must include an emphasis on following 
                    
                    all medical instructions to the letter: no escalation of doses 
                    
                    and no mixing of methadone with other prescriptions, alcohol 
                    
                    or illicit substances. Patients should be warned that any 
                    
                    deviation in this regard can be dangerous, even fatal.
Patients should be apprised of the danger of taking anyone 
                    
                    else's prescriptions and of the need to lock up all prescription 
                    
                    opioids to prevent them being stolen or consumed by others.
                  
                  
                  
References
Center for Substance Abuse Treatment, Methadone-Associated 
                    
                    Mortality: Report of a National Assessment, May 8-9, 2003. 
                    
                    CSAT Publication No. 28-03. Rockville, MD: Center for Substance 
                    
                    Abuse Treatment, Substance Abuse and Mental Health Services 
                    
                    Administration, 2004. Available 
here.
Webster LR. Methadone-related deaths. J Opioid 
                    
                    Manage. 2005;1(4):211-217.
Webster, LR, Fakata, K. Sleep Apnea Associated with Methadone 
                    
                    and Benzodiazepine Therapy Presented at the American Academy 
                    
                    of Pain Medicine 22nd Annual Meeting, February 22-25, 2006, 
                    
                    San Diego, CA. Poster 165.
RSDSA Review.
Updated October 9, 2006