Tramadol hydrochloride (trademarked as Conzip, Ryzolt, Ultracet, Ultram in the USA, Ralivia, Zytram XL Durella{CR-100/200mg} in Canada or Adolonta in Spain) is a centrally acting synthetic analgesic used to treat moderate to moderately severe pain. The drug has a wide range of applications, including treatment of rheumatoid arthritis, restless legs syndrome, motor neurone disease and fibromyalgia.