Tramadol is a centrally acting opioid analgesic with a multimode of action. It acts on serotonergic and noradrenergic nociception, while its metabolite O-desmethyl tramadol acts on the µ-opioid receptor. Its analgesic potency is claimed to be about one-tenth that of morphine. Tramadol is used to treat both acute and chronic pain of moderate to (moderately) […]