RESUMEN
INTRODUCTION: Tramadol is a weak opioid analgesic used as a step two analgesic, approved in France for the treatment of moderate to severe pain in adult patients. The most common side effects are gastrointestinal and neurologic. Hypoglycaemia is an almost unknown side effect. CASE REPORTS: We report two patients who presented with severe hypoglycaemia related to oral administration of tramadol in non diabetic patients. The underlying mechanisms of hypoglycaemia induced by tramadol are unclear. The only weak opioid analgesic drug reported to cause hypoglycaemia is propoxyphene, which has been widely used in France. The recent withdrawal of dextropropoxyphene in France might increase the prescriptions of tramadol and healthcare professionals should be aware of the risk of hypoglycaemia. CONCLUSION: The risk of hypoglycaemia should be added to the summary of product characteristics of tramadol.