within the last 5 years or so.

It is not an innocuous drug. And many doctors are unaware of its potential.

Also when used for pain management, it is hard to titrate to individuals.
The length of time it remains on pain receptors is shorter than its half life in the body. This means higher doses may be needed for pain relief than for addiction control. Higher doses, combined with other drugs or dehydration with loss of electrolytes make it dangerous for some.

So it has to be handled carefully, and patients screened and informed.

On the plus side, methadone is inexpensive and less likely to cause euphoria and hence drug abuse in long term situations.

While methadone has been dispensed for many years in rehab situations, its full impact was not understood until recently.
here is a CDC report that shows how alarming the increase in poisoning deaths has become:
http://www.cdc.gov/nchs/products/pub...one1999-04.htm

The only way to prevent this alarming trend is to educate patients, so that they insist on their doctor being experienced with methadone treatment.