The study
A large study of around 330,000 patients between 1998 and 2012 that used case-control analysis aimed to assess the risk of hospitalisation due to hypoglycaemia in patients taking tramadol compared with patients taking codeine for non-cancer pain.
Data from the hospital episodes statistics database was used, which documents details of all hospital admissions.
The findings
1 The risk of hospitalisation due to hypoglycaemia in patients given tramadol was more than twice that of patients given codeine.
2 The highest risk was when the drug was started.
3 This was the case in patients who were receiving anti-diabetic drugs and those who were not (more than 40% of cases).
4 Several confounding factors were considered. One of the most important of these was that drug adherence levels were not known.
5 It is thought that the physiological reasons for this are related to the effects of tramadol on opioid receptions and serotonin-noradrenaline reuptake.
What does it mean for GPs?
When deciding between tramadol and codeine for pain relief, GPs should consider the risk of severe hypoglycaemia with tramadol.
In patients who may have suffered from hypoglycaemia of an unknown, GPs should consider tramadol as a potential cause.
The paper
Dr Hamed Khan is a GP in the emergency department of St George’s, London, and a clinical lecturer. He tweets as @drhamedkhan.
