text: Tramadol is used primarily to treat mild to severe pain, both acute and chronic. There is moderate evidence for use as a second-line treatment for fibromyalgia but it is not FDA approved for this use. Its use is approved for treatment of fibromyalgia as a secondary painkiller by the NHS.
  Its analgesic effects take approximately an hour to be realized, and it takes from two to four hours to reach peak effect after oral administration with an immediate-release formulation. On a dose-by-dose basis, tramadol has about one-tenth the potency of morphine (thus 100 mg is commensurate with 10 mg morphine but may vary) and is practically equally potent when compared with pethidine and codeine. For moderate pain, its effectiveness is roughly equivalent to that of codeine in low doses and hydrocodone at very high doses. For severe pain it is less effective than morphine.
  Pain reducing effects last approximately six hours. The potency of analgesia varies considerably as it depends on an individual's genetics. People with specific variants of CYP2D6 enzymes may not produce adequate amounts of the active metabolite (desmetramadol) for effective pain control.
  Sleep medicine physicians sometimes prescribe tramadol (or other opiate medications) for refractory restless legs syndrome (RLS); that is, RLS that does not respond adequately to treatment with first-line medications such as dopamine agonists (like pramipexole) or alpha-2-delta (αδ) ligands (gabapentinoids), often due to augmentation.