Phenytoin injection and Rimantadine Hydrochloride

• Generic Name: phenytoin
• Dosage Forms: n.a.
• Other Brand Names: Dilantin, Phenytek, Dilantin Infatabs, Phenytoin Sodium, Prompt

Phenytoin injection is an anticonvulsant medication that is used to treat a prolonged seizure (status epilepticus). Phenytoin injection is also used to prevent seizures during a surgery.

Phenytoin injection may also be used for purposes not listed in this medication guide.

• Generic Name: rimantadine
• Dosage Forms: n.a.
• Other Brand Names: Flumadine

Has been used for treatment of influenza caused by susceptible influenza A viruses in adults ≥17 years of age.

Amantadine and rimantadine have little or no activity against influenza B; not used for treatment of influenza B infection.

Beginning in the 2005–2006 influenza season, most influenza A (H3N2) strains circulating in the US were resistant to adamantanes (amantadine, rimantadine), and resistance to the drugs among seasonal influenza A (H3N2) isolates has remained high during subsequent influenza seasons. In addition, the influenza A (H1N1)pdm09 virus circulating during recent influenza seasons is resistant to amantadine and rimantadine.

CDC and other experts recommend that adamantanes (amantadine, rimantadine) not be used for treatment of seasonal influenza in the US until susceptibility to these antiviral agents has been reestablished in circulating influenza A viruses.

Consider viral surveillance data available from local and state health departments and the CDC when selecting an antiviral for treatment of seasonal influenza. Strains of circulating influenza viruses and the antiviral susceptibility of these strains constantly evolve.

CDC issues recommendations concerning use of antivirals for treatment of influenza, and these recommendations are updated as needed during each influenza season. Information regarding influenza surveillance and updated recommendations for treatment of seasonal influenza are available from CDC.

Prevention of Seasonal Influenza A Virus Infections

Has been used for prophylaxis of influenza infection caused by susceptible influenza A viruses in adults, adolescents, and children ≥1 year of age.

Amantadine and rimantadine have little or no activity against influenza B; not used for prevention of influenza B infection.

Annual vaccination with seasonal influenza virus vaccine, as recommended by the US Public Health Service Advisory Committee on Immunization Practices (ACIP), is the primary means of preventing seasonal influenza and its severe complications. Prophylaxis with an appropriate antiviral active against circulating influenza strains is considered an adjunct to vaccination for control and prevention of influenza in certain individuals.

CDC and other experts recommend that adamantanes (amantadine, rimantadine) not be used for prevention of influenza in the US until susceptibility to these antiviral agents has been reestablished in circulating influenza A viruses.

Consider viral surveillance data available from local and state health departments and the CDC when selecting an antiviral for prophylaxis of influenza. Strains of circulating influenza viruses and the antiviral susceptibility of these strains constantly evolve.

CDC issues recommendations concerning use of antivirals for prophylaxis of influenza, and these recommendations are updated as needed during each influenza season. Information regarding influenza surveillance and updated recommendations for prevention of seasonal influenza are available from CDC.

Avian Influenza A Virus Infections

Has been recommended as alternative for treatment or prophylaxis of avian influenza A virus infections in certain situations.

CDC and WHO recommend use of a neuraminidase inhibitor (oseltamivir, zanamivir) for treatment or prophylaxis of avian influenza A infections.

If neuraminidase inhibitors unavailable, use of amantadine or rimantadine might be considered an alternative if local surveillance data indicate the strain is known or likely to be susceptible. Avian influenza A (H5N1) and avian influenza A (H7N9) generally have been resistant to adamantanes.