Tramadol is a synthetic analogue of codeine that binds to μ-opioid receptors and inhibits norepinephrine and serotonin reuptake. It is rapidly and extensively absorbed after oral doses and is metabolized in the liver. Analgesia begins within one hour and starts to peak in two hours. In patients with moderate postoperative pain, parenteral tramadol is roughly equal in efficacy to morphine, but for severe acute pain, tramadol is less effective than morphine. In studies comparing oral tramadol (up to 300 mg/d) with oral morphine for moderate cancer pain, analgesic efficacy was equivalent, but constipation, nausea, neuropsychological symptoms, and pruritus were reported more frequently with morphine.[1,2] Slow release formulations have also been shown to provide effective relief of moderate cancer pain.[3] It is not classed as a 'controlled drug' which has some practical advantages for its prescribing.