BACKGROUND: Influenza is a highly contagious viral infection of the respiratory 
system. To attack two processes involved in flu pathogenesis-viral replication 
in the infected body and oxidative damages, we studied the combination effect of 
neuraminidase inhibitor oseltamivir and antioxidant α-tocopherol in experimental 
model of influenza.
METHODS: After inoculation of albino mice with 10 MLD50 (50% mouse lethal dose) 
of influenza virus A/Aichi/2/68 (H3N2), oseltamivir was applied orally at three 
doses, 2.5 mg/kg, 1.25 mg/kg, and 0.625 mg/kg, for five days post infection. 
α-Tocopherol (120 mg/kg, in sunflower oil) was administered intraperitoneally. 
Three schemes of α-tocopherol five-day course were tested: onset five or two 
days before infection, or on the virus inoculation day.
RESULTS: Strongly dose-dependent augmented antiviral effect of the combination 
α-tocopherol and 0.625 mg/kg oseltamivir was demonstrated when α-tocopherol was 
administered simultaneously with oseltamivir: a pronounced decrease in mortality 
rate (a 78% protection), and a lengthening of mean survival time by 3.2-4 days. 
Lung parameters showed a substantial decrease in infectious virus content 
(Δ logs = 3.8/4.1) and a marked diminishment of lung index and pathology. 
Combination α-tocopherol with 1.25 mg/kg oseltamivir manifested a marked 
protective effect, but the effect on lung parameters was less. The combination 
effect of α-tocopherol with 2.5 mg/kg oseltamivir did not surpass the 
monotherapeutic effect of oseltamivir. When α-tocopherol was applied in courses 
starting five or two days before infection, its combination with oseltamivir was 
ineffective.
CONCLUSIONS: Evidently, α-tocopherol could be considered as prospective 
component of influenza therapy in combination with oseltamivir.