Alovudine (fluorothymidine) is an antiviral agent which was being developed by Medivir. It was discontinued after a Phase II trial in 2005 due to toxicity. It is a DNA polymerase inhibitor. Alovudine (fluorothymidine) is an antiviral agent which was being developed by Medivir. It was discontinued after a Phase II trial in 2005 due to toxicity. It is a DNA polymerase inhibitor.