Logistic issues and potential prescribing costs associated with use of neuraminidase inhibitors for the treatment of influenza in primary care.

In the UK, the National Institute for Clinical Excellence has recommended the use of neuraminidase inhibitors for elderly and at-risk patients who present with influenza-like illness within 36 hours of symptom onset. However, few data exist to enable primary care trusts to evaluate the logistics and costs of prescribing. We sought to determine, during a confirmed influenza outbreak, the proportion of eligible patients who currently present in time to benefit from treatment with a neuraminidase inhibitor, and to develop the findings into a model for evaluating potential prescribing costs. Within a single primary care group, demographic and co-morbidity data were collected on all patients consulting their general practitioner or attending an out-of-hours centre with influenza-like illness during the outbreak period. A typical primary care trust serving 100 000 patients might expect to prescribe a neuraminidase inhibitor to 140 eligible at-risk patients in a season of low influenza activity, rising to 300 in a large epidemic. At-risk patients were more likely than non-at-risk patients to consult within 36 hours of the onset of symptoms. However, only 20% of such patients, rising to 47% in out-of-hours centres, consulted in time to benefit from treatment. The low proportion of elderly and at-risk patients who consult their general practitioner in time to benefit from treatment with a neuraminidase inhibitor emphasizes the overriding importance of annual vaccination in these groups. If the full benefits of neuraminidase inhibitors are to be realized, access to treatment for eligible patients must be improved.