Letters A/H1N1 flu

NSAIDs and flu

BMJ 2009; 338 doi: http://dx.doi.org/10.1136/bmj.b2345 (Published 15 June 2009) Cite this as: BMJ 2009;338:b2345
  1. Rokuro Hama, chairperson1
  1. 1Japan Institute of Pharmacovigilance, 902 Ueshio3-2-17, Tennoji-ku Osaka, Japan 543-0002
  1. gec00724{at}nifty.com

    The potentially harmful effects of non-steroidal anti-inflammatory drugs (NSAIDs) are rarely discussed in the treatment of A/H1N1 flu, which has caused high death rates in Mexico.1 2

    Severe and fatal cases, including sudden death, are characterised by severe sepsis with multi-organ failure with findings such as fever, leucocytosis, leucopenia, acute respiratory distress syndrome (ARDS), liver impairment, renal failure, rhabdomyolysis, and hypotension.2 NSAIDs may aggravate these syndromes, leading to multi-organ failure.3

    Since the flu pandemics of the 20th century salicylates have been linked to Reye’s syndrome and their use restricted in children. But NSAIDs such as diclofenac, mefenamic acid, and ibuprofen are still used as antipyretics in many countries, albeit less often than aspirin. Since the use of diclofenac and mefenamic acid was restricted in children in Japan in 2000, the case fatality of so called flu associated encephalopathy has fallen dramatically.4

    Reanalysing the World Health Organization’s data on A/H1N1 flu,2 I found that the odds ratio of case fatality in adults (3.7%) and children and adolescents under 20 (0.5%) is 7.63 (95% confidence interval 3.78 to 15.85, P<0.001). Whether the people who died were treated with NSAIDs is not known. However, NSAIDs are readily available over the counter in Mexico and people commonly self treat.5

    Case-control studies are urgently required to assess the risks of NSAIDs as antipyretics in flu.


    Cite this as: BMJ 2009;338:b2345


    • Competing interests: None declared.