Almost exactly one year ago the Cochrane Library published an intervention review on the prevention and treatment of influenza with neuraminidase inhibitors in adults and children. The reason for this review was the fact that many countries stockpile these drugs and the WHO classified them as an essential medicine.
Jefferson et al. used the data of 46 trials with oseltamivir or zanamivir for this review. They basically conclude that:
- Both drugs shorten the duration of symptoms of influenza-like symptoms by less than a day
- Oseltamivir did not affect the number of hospitalizations
- Prophylaxis trials showed a reduced risk of symptomatic influenza in individuals and households, but no definite conclusion can be made
- Oseltamivir use was associated though with nausea, vomiting, headaches, renal and psychiatric events
...and finally write: 'The influenza virus-specific mechanism of action proposed by the producers does not fit the clinical evidence'. This review certainly undermined the importance of oseltamivir for many of us.
The Cochrane review though did not look at outcomes like mortality, but the Lancet Respiratory Medicine did! Stella G at al. have now published a large systematic review which included 29'234 patients from 78 studies during the period from 2009 to 2014. Their findings come rather surprisingly:
- Compared with no treatment, neuraminidase inhibitor treatment (irrespective of timing) was associated with a reduction in mortality risk
- Compared with later treatment, early treatment (within 2 days of symptom onset) was associated with a reduction in mortality risk
- The reduction in mortality risk was observed when treatment was started up to 5 days of symptoms onset
There still seem to be some good reasons to use oseltamivir in critically ill patients with suspected or proven influenza... up to 5 days of symptoms onset!
Jefferson T et al. The Cochrane Collaboration, Published Online: 10 APR 2014
The Cochrane Collaboration News Release 10 April 2014
Muthuri, Stella G et al. The Lancet Respiratory Medicine , Volume 2 , Issue 5 , 395 - 404