The FDA has approved peginterferon alfa-2b (Sylatron – Merck) for adjuvant treatment of node-positive melanoma after surgical resection. Pegylated interferon has a longer duration of action than interferon alfa-2b (Intron A), which is also FDA-approved for adjuvant treatment of malignant melanoma after surgery, and can be given once a week, compared to 3-5 times a week for standard interferon.

Recombinant interferon alfa-2b conjugated to polyethylene glycol (PEG-Intron), the first "pegylated"alpha interferon, has been approved by the FDA for once-a-week monotherapy of chronic hepatitis C virus (HCV) infection in patients not previously treated with alpha interferon.

Rebetron, a combination of injected recombinant interferon alfa-2b with oral ribavirin has been approved by the FDA for treatment of chronic hepatitis C virus infection.

The FDA has approved recombinant interferon alfa-2a conjugated to polyethylene glycol (Pegasys - Roche) alone or with oral ribavirin (Copegus - Roche) for treatment of adults with chronic hepatitis C virus (HCV) infections not previously treated with interferon alpha. The standard of care for treatment of most patients with hepatitis C has been once-weekly injections of peginterferon alfa-2b (PEG-Intron -Schering) plus oral ribavirin (Rebetol - Schering) (Medical Letter 2001; 43:54).

Recombinant alpha interferon has been marketed in the USA for treatment of hairy-cell leukemia, genital warts, and AIDS-related Kaposi's sarcoma (Medical Letter, 28:78, 1986; 30:70, 1988). Recent reports indicate it may also be useful for treatment of chronic viral hepatitis. Recombinant alpha interferon is available as alfa-2a (Roferon-A - Roche) or alfa-2b (Intron A - Schering), which are identical except for one amino acid.

Recombinant interferon alfa-2b (Intron A - Schering) was recently approved by the US Food and Drug Administration (FDA) for intralesional treatment of genital warts (condylomata acuminata). Interferon was previously available only for treatment of hairy-cell leukemia (Medical Letter, 28:78, 1986).

Nadofaragene firadenovec-vncg (Adstiladrin – Ferring), an adenoviral vector-based gene therapy, has been approved by the FDA for treatment of adults with high-risk Bacillus Calmette-Guérin (BCG)-unresponsive non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ with or without papillary tumors. It is the first adenoviral vector-based gene therapy to be approved in the US for this indication. The immune checkpoint inhibitor pembrolizumab (Keytruda) was approved for the same indication in 2021.

Adefovir dipivoxil (Hepsera - Gilead), a nucleotide analog, has been approved by the FDA for oral treatment of chronic active infection with hepatitis B virus (HBV). In 1999, because of concerns about renal toxicity, the FDA rejected a higher-dosage formulation of adefovir for treatment of HIV infection.

The drugs of choice for treatment of viral infections (other than HIV) and their dosages are listed in Tables 1-6 on the pages that follow. Some of the indications and dosages recommended here have not been approved by the FDA. Vaccines used for the prevention of viral infections are discussed elsewhere.