Efficacy of codeine vs. methadone

Factual Questions
1

I recently made friends with a heroin addict who is on methadone treatment; she’s been coming once a week or so to do some volunteer work here. She showed me her bottle of methadone, and I was surprised to see that the daily dose was only 25 mg. A few years ago when I burst my eardrum, the doctors prescribed me 30 mg codeine tablets for the pain. I take it, then, that methadone is much more potent than codeine. My question is, how much more potent is it? That is, how many times more codeine than methadone is required to immediately relieve a given level of pain?

(BTW, I am aware that methadone is much longer-acting than codeine, and that this is why it is used in the treatment of opiate addiction. I’m just interested in the potency, not the duration.)

2

Here is a table of the relative strengths of opioids. Seems like 10 to 13 times stronger according to route.

3

They are completely different compounds.
The number of milligrams of any drug is simply the dose for * that* drug. They are not interchangable.
A dozen oranges and a dozen pineapples don’t weigh the same.

4

Sorry, but you’re wrong. Drugs to treat the same condition are frequently substituted—for example, if someone is allergic to a particular medication, a different one with similar effects may be substituted, but the dosage may need to be adjusted accordingly. In the case of codeine and methadone, both are opiates and are used as narcotic analgesics (that is, used to relieve pain), albeit in different doses.

5

25 mg is a very low dose of methadone.

Most patients begin on 20-40mg a day, increasing in 10mg increments until no signs of withdrawal occur. The usual dosage range is 60-120mg a day.

Most of the patients I’ve seen on it have been on about 80ml a day because we use a liquid prep, this is equivalent to 80mg.

Patients on enzyme inducing medications (such as certain TB and HIV therapies) have to take higher doses to get the same effect. I know one guy in that situation who was on over 300mg of methadone a day.
If anyone is interested, about 10% of the dose of codeine ingested is converted within the liver to morphine.

6

Am I correct in assuming, though, that the dose is then gradually lowered so that the patient can be completely weaned off of their opioid addiction? If so, that might explain my friend’s 25 mg/day dosage—she says it’s been a long time since she’s taken any heroin, so perhaps she’s nearing the end of her methadone treatment and will soon be able to function without it. It might also explain why she’s allowed to take a double dose home with her instead of being made to come in once a day and drink her methadone at the clinic.

7

It depends on the particular goals of the patient.

Some people on methadone take a dose which enables them to function normally and removes their need for heroin. They may well decide to continue on that dose for the forseeable future, possibly for the rest of their life, as it gives them the safety net they need. A lot of these people may have been through the detox-recovery-relapse etc cycle several times, and might not feel they have the strength to go through it again.

Methadone, at a properly titrated dose, doesn’t make someone “high”, and as it removes the high-risk behaviour associated with heroin use (theft, prostitution, dirty needles etc) there is a logical argument that allowing someone to stay on a maintenance dose of methadone is probably in their best interest if they are very likely to relapse onto heroin if detoxed.

Some methadone patients are very active in wanting to gradually cut down their dose with the eventual goal of being completely clean. The clinic will usually work to help them with that, but they need to be highly motivated.

I spent a day in one of the state-run Dublin methadone clinics (there are about 15,000 heroin users in Dublin). Their policy is to test everyone’s urine every day when they first come to the clinic. If the person is shown to have stopped taking heroin (the test can differentiate between methadone and other opiates and opioids) the urine testing is reduced in frequency. After a certain period of time with “clean” urine (i.e. no heroin) they are allowed to take some of their doses away with them.

Eventually the most trusted patients are allowed to take 6 bottles away and drink one on the premises- allowing them to come to the clinic only once a week, although they can be called in randomly for a urine test. Any “dirty” urine and they have to go back to attending the clinic every day and drinking all their methadone on site.

You may be shocked to hear this, but although the clinic also tests for cannabis, cocaine, benzodiazepines, amphetamines, ecstasy, and LSD, the presence of any of these substances is not considered to be a “dirty” sample. Many heroin addicts are also addicted to benzodiazepines, which it is very dangerous to detox from without medical supervision, the clinic will often also supply these tablets with the methadone. People are offered drug counselling, AA and NA, but attendance at any of these is voluntary. The only time someone is actually refused methadone is when they arrive at the clinic obviously high or drunk.

Basically the whole ethos is about harm-reduction. getting people completely clean and sober is less of a priority than making sure that the more dangerous aspects of drug use are reduced. With about 90% of Dublin heroin addicts positive for Hepatitis C and 10% positive for HIV, and most turing to crime to support their habit, you can see why the focus is on the heroin use.

8

I certainly am shocked to hear that they test for LSD. Given that an effective dose can be as little as a few dozen micrograms, most of which is metabolized, how on earth do they detect any evidence of use in the urine? I mean, I’m not saying it’s absolutely impossible to do, but given the minute quantities involved, plus the fact that LSD isn’t addictive and is thus unlikely to lead to criminal behaviour, wouldn’t it be prohibitively expensive to test for it?

9

I apologize, I mis-read the OP completely. I’d just gotten up. Sorry.

10

Methadone dosing is really, really, really variable. It is very difficult to say anything hard and fast about it. It’s often considered equivalent to morphine mg for mg, but this applies in limited acute pain treatment settings, because methadone lasts soooooo long in the system. A dose that relieves their pain on day 1 may make them unconscious by day 5 if taken continually because it has built up in their system.

I use it rarely (almost never, actually) for acute pain, but prescribe it more often for chronic malignant pain, with shorter-acting opioids to be used for breakthru. I use it in a few chronic non-malignant pain patients when there are no other good options. I like it a lot better as a chronic pain med than MS Contin or Oxycontin, because it gives good pain relief with less euphoria than than those other two drugs.

11

Please note also that using methadone maintenance to treat and/or maintain chronic opiate addiction (heroin usually) is very very very very different from using methadone to treat pain.

In the US, a special certificate is needed from the DEA to prescribe methadone to maintain an addiction, or to detox a patient. No such certificiate is needed (only the usual DEA number) to prescribe it for pain.

12

These are regimens for treating addiction, not pain, no? Dosing for pain treatment tends to be done differently.

13

Sorry, I went to graduate school in neuroscience/psychopharamcology. picnurse is right. Your take on that is extremely confused.

The strengths of different drugs cannot be compared by looking at the physical dose size. There are lots of variables that go into this and they are complicated and extremely important on the effects of the drug.

You seem to realize that drugs like LSD have doses in the microgram range while other drugs that affect the nervous system have physical drugs sizes many times greater. That difference does not stop when you move to drugs that are in the same class. Opiates vary tremendously in the dose size needed for a particular effect. Receptors have an “affinity” for a particular drug and even similar drugs may have different affinities requiring them to have different doses for the same effect.

Dose tells you very little by itself and you ceratinly can’t ever use them to do blind comparisions between drugs.

14

I think you two are the ones that are confused. I apologize if this is the result of my not using standard medical terminology.

I’m sure they can when the only factor you’re varying is the drug. It’s an application of the scientific method.

Not as far as my question is concerned. The only variables I’m interested in are the drug and the dose. I am assuming all other variables (method of administration, condition to be treated, patient’s body weight, etc.) are equal.

I am aware of this; it was the very basis of my question. I wanted to know exactly what variation in dose size between methadone and codeine is typically required for the same particular effect (that is, pain relief). As far as I know, don’t ask provided a reference to the correct answer. Is it your contention that his reference is incorrect?

15

That is as good a reference as one can expect. However, the opiates are not equal even if you control for dose. Oxycontin does not equal heroin does not equal morphine does not equal methadone. You can’t just pull out a dosage equivalence chart and conclude that their effects will be equal as long as you adjust for dose and route of administration.

They are fundamentally different drugs even if they are grouped together because they work on opiate receptors in the brain.

16

I never said that they were; in fact, I specifically mentioned that I was aware there were differences such as the duration of effect. But I also stated that I wasn’t concerned with any effect other than pain relief. I know that if I have a headache, I can take, say, 250 mg of aspirin or 8 mg of codeine, and they’ll be just as effective at killing my headache for at least an hour, even though only the former also has anti-inflammatory properties and only the later will make me drowsy. But for the purposes of my query, I don’t care. I’m interested in measuring the effect of exactly two independent variables (drug and dosage) on exactly one dependent variable (pain relief). The fact that different values of the two independent variables may affect other dependent variables is irrelevant.

17

It is impossible to be exact in dosing as Shagnasty says . However doctors know that for similar drugs (e.g. morphine, oxycodeine, methadone) there is an approximate dosing equivalent e.g. 30 mg methadone = 15 mg morphine or whatever. They do this all the time if they try a new drug if the old old one isnt working. Howver, Shagnastys point isnt very useful as of course drug efficacy varies from patient to patient, each disease is different from stage to stage, or even during the course of one disease. No one knows *for sure * what the best dose for any particular patient is or nor much to substitute one drug for another is. All one can do is rely on limited data from drug trials, look up the recommended dose in your black book and hope for the best.

18

The linked reference says that heroin (diacetylmorphine) “metabolizes to morphine very quickly–with a half-life of roughly 3 minutes. The half-life of morphine is reported.”

Does your statement still hold?

19

My aunt was put on methadone when she got really sick with cancer. It was the only thing that really relieved her pain.

20

Absolutely. Pharmacology is complicated and small differences between drugs can mean big differences and science and medicine still can’t predict them all that well.

In this example, heroin acts as heroin and then it also gets to act as morphine further down the metabolic pathway. Morphine doesn’t get metabolized to heroin. Those first few minutes are important to heroin’s appeal as a recreational drug.

Just because two drugs are both opiates don’t mean they act exactly the same way. There are different types of opiate receptors and different drugs have different profiles depending on their affinity for those receptors. The human brain is the most complex thing known to man and slightly different actions by different drugs can mean big differences. Combine that with different metabolic profiles and other things I am sure you can see why one doesn’t equal the other.