[Severe hypoglycemia following tramadol intake in a 79 year old non-diabetic patient]

History and clinical findings | We report about a 79 year old non-diabetic patient who was admitted to the emergency room with severe hypoglycemia (blood glucose level: 36 mg / dl and Glasgow Coma Scale Score: 3). After the infusion of G40 % her blood glucose level stabilised. The patient reported to have taken 50 mg of Tramadol during the night to treat her headache. Investigations and diagnosis | No other differential diagnosis for hypoglycemia (i.e. diabetes, insulinoma, severe liver or kidney disease) could be established. Therefore, we suspected a tramadol induced hypoglycemia. The mechanisms and the risk factors for this potential side effect remain unclear. The patient showed no abnormality in metabolism (CYP2D6) or membrane transport (OCT1) of tramadol. Treatment and course | No further treatment for hypoglycemic episodes was needed. The patient was discharged after the differential diagnosis and pharmacogenetic testing was completed. Conclusions | Hypoglycemia is a little known adverse effect after tramadol intake, which has only been published in few cases. Tramadol, a weak opioid analgesic classified as step 2 of the WHO cancer pain ladder, is used in moderate pain. Given the continuous rise in tramadol prescription due to better management of chronic pain, further investigation of this issue seems needed as well as an increased awareness amongst physicians.