Methadone has numerous advantages as an analgesic, which have supported its recent increase in use. However, methadone also has a pharmacological profile as an opioid that differentiates it from other, better known or more widely used opioids. It also has unusual pharmacodynamics, pharmacokinetics, and metabolism that must be considered for safe use of methadone as an analgesic. This review looks at the history of methadone use as an analgesic and its properties that distinguish it as an unusual, and potentially, unstable opioid.

In recent years, opioid therapy for the management of chronic noncancer pain has become more widely accepted following the publication of data demonstrating the efficacy of this class of drugs in a variety of pain conditions, including osteoarthritis, neuropathic pain, and low back pain. An array of short-acting and long-acting opioids has been formulated to help prescribers more effectively tailor the management of chronic pain based on the quality and temporal profile of the pain as well as the functional goals of the individual patient. Evidence suggests that both of these groups of medications offer unique benefits to individual patients and that neither is more efficacious than the other. Rather, both short-acting and long-acting opioids should be considered in the overall pharmacotherapeutic treatment of patients with chronic noncancer pain.

A high prevalence of clinical and biochemical VDD was noted in apparently healthy children belonging to the USES.

Pulsed RFL of the GON is an alternative to continuous RFL with the proposed advantage of mitigating pain, as in continuous RFL, but without the potential risk of causing deafferentation pain. While placebo and other nonspecific analgesic effects cannot be ruled out, the apparent safety profile and potential efficacy of pulsed RFL suggests it may be a compelling option to consider before irreversible neuroablative therapies are applied.

While the evidence for urine drug testing for patients on chronic opioid therapy is weak, the guidelines created by numerous medical societies and state and federal regulatory agencies recommend that it be included as one of the tools used to monitor patients for compliance with chronic opioid therapy. To get the most comprehensive results, clinicians should order both an immunoassay screen and confirmatory urine drug test. The immunoassay screen, which can be performed as an in-office point-of-care test or as a laboratory-based test, is a cheap and convenient study to order. Limitations of an immunoassay screen, however, include having a high threshold of detectability and only providing qualitative information about a select number of drug classes. Because of these restrictions, clinicians should understand that immunoassay screens have high false-positive and false-negative rates. Despite these limitations, though, the results can assist the clinician with making preliminary treatment decisions. In comparison, a confirmatory urine drug test, which can only be performed as a laboratory-based test, has a lower threshold of detectability and provides both qualitative and quantitative information. A urine drug test's greater degree of specificity allows for a relatively low false-negative and false-positive rate in contrast to an immunoassay screen. Like any other diagnostic test, an immunoassay screen and a confirmatory urine drug test both possess limitations. Clinicians must keep this in mind when interpreting an unexpected test result and consult with their laboratory when in doubt about the meaning of the test result to avoid making erroneous decisions that negatively impact both the patient and clinician.