What does ‘analge sia’ mean?

In fact, you guys could just help me understand what the whole paragraph is saying:

Acute Pain

Maintenance patients on a stable dose of methadone who experience physical trauma, postoperative pain or other acute pain cannot be expected to derive analge sia from their ongoing dose of methadone. Such patients should be administered analgesics, including opioids, in doses that would otherwise be indicated for non-methadone-treated patients with similar painful conditions. Due to the opioid tolerance induced by methadone, when opioids are required for management of acute pain in methadone patients, somewhat higher and/or more frequent doses will often be required than would be the case for non-tolerant patients.

Bottom Line: People on methadone with acute pain need pain killers just like people who are not on methadone only at more frequent intervals or at a higher dosage.