Almost all other opiate pain relievers (percocet, lortab, lorcet, vicodin, darvocet, etc) are short acting.  They work quite well at first though only for a certain amount of time.  Methadone is the only pain medication that accumulates in the body.  Meaning after taking it for a while your body starts to store it.  Which is a great thing for people with chronic pain and addictions to pain pills, heroin.

No other pain medication has this action of buildup in the body.

Methadone is a very affordable drug.  The cost of methadone is very low compared to almost any other pain mediaction.  There are couple of meds that cost about the same (Generic darvocet, and vicodin (hydrocodone).

Addiction of Pain Pills

There are 2 different addictions:

1.  Physical addiction:  The body needing a dose at the time of the next dose, of no dose is taken then withdrawal begins.

2.  Physchological addiction:  This is when you just want and have a craving to take pills for the high.

Pain pills do make you feel good (euphoric feeling of well being).  Getting high is what you can call it.  The more pain you are in the less of a high you get.  As with any narcotic, there is the potential of addiction.  The reason doctors do now want you to take pain medications too often, such as 1 every 6 hours is that the more you take the closer you get to becoming addicted.  Even though you pain needs more medication.  If pain pills are taken too often every day and night for about 15-20 days or more your body body begins to require the pills just to keep the brain satisfied and to keep withdrawal at bay...

The more pills you take the more you need.  This cycle snowballs.  The more tolerant you become usually means the more addicted you are becoming.