Combined administration of oseltamivir and hochu-ekki-to (TJ-41) dramatically decreases the viral load in lungs of senescence-accelerated mice during influenza virus infection.

To enhance the effect of anti-influenza-virus agent treatment, the effect of combined administration of oseltamivir phosphate and hochu-ekki-to (Japanese traditional herbal medicine, HET) on early viral clearance was examined. Senescence-accelerated mice were given HET in drinking water for 2 weeks, followed by intranasal infection with influenza A virus strain PR8. After 4 hours of infection, oseltamivir was administered orally for 5 days. The viral loads in the lungs of the group receiving combined treatment were dramatically lower when compared with the viral loads in the lungs of the group receiving oseltamivir alone. HET significantly increased the induction of IL-1β and TNF-α in the lungs of PR8-infected mice and stimulated alveolar macrophage phagocytosis. From these results, we conclude that these functions may be responsible the increased effect on viral load reduction. Here, we show that the combined administration of oseltamivir and HET is very useful for influenza treatment in senescence-accelerated mice.