How Much Methadone is Enough?

Methadone is used for 'pain control' and as a substitute therapy for opiate dependence. I'm only speaking to the latter today.
When a person starts a methadone maintenance program they may be using a wide range of compounds and dosages of pills, snorted heroin or injected heroin.  If one is 'new' to their opiate dependence there are detox programs and Narcotics Anonymous as alternatives which can be done alone or in combination with 1-3 month "treatment centres" followed by group living 'recovery homes' where drugs and alcohol are banned.
"New" usually means the person has been using regularly but not necessarily daily for less than a year or two.  When they are at the point of daily use and experiencing 'withdrawal' symptons without opiates they are 'dependent', and not just abusing drugs.  They're 'hooked'.
People who are early in their addiction where the amounts they use and the frequency of use is low may still benefit from methadone maintenance therapy but may also be good candidates for the alternative "substitution" therapy, Suboxone - a pill form combination of buprenorphine and naloxone.  Buprenorphine is the active opiate replacement medication while naloxone is the antagonist that makes the drug 'ineffective' if it is injected.
When a person comes into the Methadone Maintenance Program the normal dosage of medication that is used to 'start' regardless of the 'amount' of drug the person was using on the street is roughly 25 to 40 mg.  The concern of the methadone doctor is 'overdose'.  No doctor wants to 'kill' a patient to 'help' them. There is no way to know 'what' a person has been using on the street, since there is fluctuating purity of compounds and commonly dilutions.  It is understood that the 'starting' dosage is often not enough to stop the cravings and even other withdrawal symptons such as sweating, wide pupils etc. If a person has been injecting a whole lot of heroin this dosage of methadone may only take the 'edge' off.  People often take heroin in their early stage of starting methadone because they can't tolerate or wait for the right amount of methadone to be reached. The dosage of methadone is then increased every 5 to 10 days by the maximum amount of 10 mg to the dosage which is 'enough' for the individual patient.
The 'right' amount of methadone is that dosage which stops 'withdrawal symptons' and addresses specifically the 'physical' craving symptons.  The physical craving symptons are different from the 'psychological' craving. With psychologically craving all manner of expectations are associated with the 'getting high' or 'escape' the drug gives. A person knows they have reached the state of not having 'physical craving' when indeed the person is using methadone and if they try heroin say, "It doesn't work for me...it doesn't get me high anymore...it's wasting my money'.  The methadone at that point is blocking the opiate receptors.
Psychological craving is associated with the psychological aspects of peoples continued use of drugs past what they bodily "need."  Asked why they kept using some admittedly say "I had nothing else to do.... I was bored...... I thought I'd get higher..... I was lonely....The drugs were there.....  I just wanted to pass out. "  The psychological craving is part of the 'crazy' of drug doing. It's why overdose and death are common among heroin users.  Addiction is a deadly disease.
The World Health Organizations studies showed that people who were on at least 60 to 80 mg of methadone a day did better in the long run, staying in the programs, getting into Recovery, not relapsing to street heroin, than those using only 20 or 30 mg of heroin.  These are looking at large numbers. I have a couple of patients using less than 40 mg but their street use was low and infrequent. Further the lower dosage seems more likely a successful solution for those who snort rather than those who use IV heroin.  Suboxone may indeed be a better alternative overall for this group.  Others on low dose are slowly being tapered off,as they have done well on higher dosages, are off other drugs, have stable lives, may be back at work or school and generally are succeeding in the community.  This is when a patient may be on a slow taper but get to a very low dosage where it takes some time to come off 'the last little bit'.
Therefore anything under 100 mg of methadone can be consider standard or moderate dosage.  I have other patients on 220 mg and know of others on more. 200 mg is more in the 'high dosage' range. Patients who are on methadone for years, with 'clean urines', jobs and families, may over time need to increase or may decrease their methadone dosage. The dosage is a matter between the doctor and patient. It should never be 'judged' out of context.  Many of my patients who became 'hooked' on opiates following trauma who still have chronic pain but lost control of their prescription drug use for whatever reason, get back to normal lives on methadone maintenance but continue on the methadone for 'pain control' and just simply stay in the methadone maintenance programs. I have seen patients whose 'addiction' behaviourally was addressed years ago and they have been drug free and are living wholly normal lives in the community but continue to see the methadone maintenance doctors esssentially as they might see a 'pain specialist prescribing methadone'.
There are individuals who are 'rapid methadone metabolizers' and they need a higher dosage and may even need to have their methadone split to being administered twice a day.  To know if a person is a rapid metabolizer, the symptomatic picture is that the patient feels well immediately after but by evening or early morning is experiencing withdrawal. The doctor and the lab then do a series of blood level measurements after the methadone is taken to establish the peak and trough of the drug level and see when this is occuring. In rapid metabolizers the peak is the same as others but the trough occurs much more rapidly and remains low causing the patient the discomfort.  This may occasion a higher dosage than normal or splitting the methadone into two doses morning and evening.
Also crystal methamphetamine and cocaine will influence the subjective need for methadone as both are stimulants result in the patient physiologically or psychologically (or both) 'needing and wanting' more methadone to do the job. Commonly when patients stop their cocaine or crystal meth abuse their 'need' for methadone reduces drastically.
That said, some patients have other medications on board and if any are metabolized by the same system that metabolizes methadone or are associated with respiratory depression these have to be seriously considered. Benzodiazepines , (diazepam, clonazepam, lorazepam, etc) are all contraindicated in combination with methadone as the combination was the cause of death in sleep and overdose with methadone methadone maintenance programs. Indeed the prevailing wisdom to date as a result of  scientific evidence is that opiates and benzodiazpines are contraindicated together in general.
With all these considerations I asked Dr. G. Horvath, a leading authority on the clinical use of methadone, on how he would assess if a patient was on enough or too much methadone. Dr. Horvath is an addiction medicine specialist with a very extensive clinical experience in the Downtown Eastside Vancouver  where he has the Doc-Side Medical clinic in which a half dozen methadone doctors practice as well. As one doctor said, "he's seen it all'.  No one has but he's closer than most.
He wasn't terribly concerned about the 'dosage' even into the 200 range.
"If you are ever concerned about the dosage being too high, arrange with the pharmacist to know the actual time the medication was witnessed, then see the patient between 4 and 6 hours later. If they are not drowsy at that time then the dosage isn't too high. If you want to be even more scientific get a peak and trough level for the drug from the lab to ensure you're assessing their level of consciousness at the peak level of the drug. You can check the pupil size too."
This was extremely beneficial information to learn not just for the measurement of the 'dosage' in clinical practice,  but for me to answer questions from treatment centers,   therapists and others who have patients in mixed meetings where some of the people attending are on methadone and others are not.  Complaints sometimes arise that persons on methadone negatively affect meetings by being 'on the nod' and not able to 'participate'.  In the majority of cases I was asked about the individuals depressed state of consciousness was the consequence of benzodiazepines or other medications which the treating methadone doctor did not know about.
There are countless patients with legitimate pain legitimately on opiate medication attending advanced education and training without being obtunded and passing out in the classes.  When this is happening it should be seen as a red flag. Dosage of medication needs to be assessed with the prescribing doctor and  pharmacist and urine testing needs to be done to confirm that only methadone is being used.  The stat random urine test is best if a person appears too drowsy to participate and a person thinks their methadone level may be the cause. As I have said the most common cause is other drug abuse or use of other medications that the methadone doctor may not be aware of.  Most commonly the drowsiness in the cases I investigated was the excessive marijuana usage or benzodiazepine abuse or abuse of other opiates in addition to the methadone.
Here in Vancouver we have the benefit of an enlightened Minister of Health and pharmanet program which allows us to review easily what has been prescribed to an individual patient. Urine drug testing is a standard part of methadone maintenance programs and if there is a concern a "STAT" urine drug test can be ordered any time.
  However, in many other cases the methadone patient in the classroom who was nodding off was doing so because of poor sleep, sleep apnea, homelessness or even because the lecturer was utterly boring.  Many other explanations need to be considered.  Too often it is assumed that methadone or the 'dosage' of methadone is the issue.  Of course , sometimes it may be, but more often than not, that's not the case.
Commonly, the problem with a patient dropping out of methadone maintenance and returning to street heroin use is that the methadone dose isn't enough. There is a 'right' dosage which is specific to the individual.  That's when the Methadone Dosage is "enough".