In accordance with the present invention there is provided a pharmaceutical composition useful for the treatment or prophylaxis of viral infections comprising tipranavir and at least one antiviral active compound of formula (I) ##STR00001## wherein Base is selected from the group consisting of thymine, cytosine, adenine, guanine, inosine, uracil, 5-ethyluracil and 2,6-diaminopurine, or a pharmaceutically acceptable salt or prodrug thereof.