Can tramadol really induce hyponatraemia? A pharmacovigilance study

Area of Science:

• Pharmacovigilance
• Clinical Pharmacology
• Drug Safety

Background:

• Hyponatraemia has been reported with tramadol use in several studies.
• Confounding factors often complicate the direct association between tramadol and hyponatraemia.

Purpose of the Study:

• To investigate the potential association between tramadol monotherapy and hyponatraemia.
• To analyze data from the WHO pharmacovigilance database (VigiBase®) for safety signals.

Main Methods:

• Utilized individual case safety reports (ICSRs) from VigiBase® (1992-2019).
• Performed disproportionality analyses, including analyses excluding concomitant hyponatraemic drugs.
• Calculated reporting odds ratios (ROR) and information component (IC) to assess the association.

Main Results:

• A significant association between tramadol and hyponatraemia was initially observed (ROR = 1.49).
• This association disappeared after excluding reports of concomitant hyponatraemic drug use.
• No pharmacovigilance signal for tramadol monotherapy and hyponatraemia was detected.

Conclusions:

• The study suggests that tramadol alone is unlikely to be a direct cause of hyponatraemia.
• Reported cases of hyponatraemia with tramadol are likely attributable to other underlying conditions or concomitant medications.
• Further investigation into confounding factors is crucial when evaluating drug-associated adverse events.