Tramadol hydrochloride {(1RS, 2RS)-2-[dimethylamino] methyl]-1-(-3-methoxyphenyl) - cyclohexanol hydrocholoride)} is a commonly prescribed analgesic that is licensed in the UK for moderate to severe pain. Its analgesic action is mainly as a result of its serotonin and noradrenalin reuptake inhibitor (SNRI) like activity 2. However, the more commonly promoted mode of action is as a μ-receptor opioid agonist, for which it has only a weak affinity.
Despite its mode of action, specific features of SNRI toxicity have not previously been reported with tramadol overdose. Furthermore, within the tramadol Summary of Product Characteristics and several toxicology databases the treatment of tramadol overdose focuses on reversing opioid toxicity alone. We present a case of tramadol overdose complicated by combined features of opioid toxicity and SNRI toxicity.