Nieuwe influenza A (H1N1): geadviseerde indicatie en voorschrijfgedrag van antivirale middelen

AIM: To evaluate to what extent antiviral drugs have been prescribed to patients other than confirmed cases and their contacts since the emergence of New Influenza A (H1N1).

DESIGN: Descriptive.

METHODS: We inspected monthly and annual counts of oseltamivir (Tamiflu) and zanamivir (Relenza) prescriptions dispensed by public pharmacies in the Netherlands from 2005 until 30 June 2009. We compared these figures with counts of antiviral cures supplied by the Netherlands Vaccine Institute (NVI) to Municipal Health Services (GGDs) for the treatment of confirmed cases and contacts up until 1 July 2009.

RESULTS: Counts of oseltamivir prescriptions dispensed by public pharmacies started to increase in April 2009. Although this increase might seem limited compared to increases in 2005/2006 triggered by avian influenza in Turkey, up to 1 July 2009 oseltamivir was dispensed 9069 times, which is 9 times more often than in 2007 and 15 times more often than in 2008. This total was also approximately 10 times more than that dispensed by Municipal Health Services to confirmed cases of H1N1 infection and their contacts. General practitioners prescribed 78% of the prescriptions dispensed. Counts of zanamivir prescriptions dispensed hardly increased.

CONCLUSION: The counts of oseltamivir prescriptions dispensed by Dutch public pharmacies has increased, even though patients with a confirmed H1N1 infection and their contacts had already been treated by the Municipal Health Services. Therefore it cannot be excluded that this increase is due to prescription on a precautionary basis. To avoid unnecessary risks for the spread of resistant strains and a shortage of antivirals later in the epidemic, physicians should refrain from prescribing antiviral drugs if patients do not match the nationally advised medical grounds for treatment.