Tramadol hydrochloride (Figure 1) is an analgesic agent, used to treat a range of pain syndromes , and is a synthetic opioid structurally related to morphine and codeine . The marketed tramadol hydrochloride (HCl), ULTRAM®, is available in the USA, along with over 90 countries . In the past tramadol has been classified as a low abuse potential drug, enabling it to be classified as a non-controlled drug . Tramadol is available in capsule form, drops, sustained-release formulations and as solutions for intravenous and subcutaneous injection . The WHO, in their 36th ECDD Tramadol review report described tramadol as a 2-step analgesic in the WHO guidelines for the relief of cancer ; with tramadol also applied in cases of acute and chronic pain . Since 2007, China’s FDA has marked tramadol as a ‘second category psychoactive substance’ .