Methadone Drug Interactions
According to Methadone Today, "The official newsletter of Detroit Organizational Needs in Treatment (DONT)", certain drugs will change the levels of methadone the blood-stream. This is one of the reasons that people on methadone maintenance sometimes complain that their dose on a particular day does not "hold them". This is also an issue that affects those using methadone to detox them, because it can cause their dosage to fluctuate--making the withdrawal more turbulent.
Avoid Opioid Antagonists
Not surprisingly, any of the opioid antagonists or mixed agonist-antagonists lower the body's methadone levels. This is done by ripping them from the opioid receptors where the liver can biotransform them into inactive metabolites.
|Drugs with Antagonist Activity|
Tramadol (Ultram®) is not considered an opioid, but in fact, it is. It is simply that it does not depend solely on its opioid quality for its pain relieving ability. As a result of its action, it effects methadone levels as a mixed agonist-antagonist. It should be avoided by those using methadone.
Decreasing Methadone Levels
Many drugs may lower methadone blood levels. The most important, without doubt, is alcohol. Other sedative/hypnotics such as the barbiturates act the same. No mention is made of the benzodiazepines (for example, Valium®) having this effect, but if in doubt, it would be prudent to avoid them.
Drugs for the treatment of convulsions and pulmonary tuberculosis can also decrease methadone levels. Even Vitamin C should be avoided because it causes methadone to be excreted more quickly (this is a common tool used by drug users who are subject to urine testing).
Information is Power
The main point of this article is that people who are using methadone should be aware that the effectiveness of the drug can be greatly affected outside factors. It would be a mistake to assume that simply because one is a patient at a methadone clinic that those responsible for their care know about these issues. It is always a good idea to become as knowledgeable as possible.
A more detailed discussion of these effects can be found in the article Drugs Which May Lower Methadone Serum Blood Levels in Methadone Today Volume 2, Number 8.