Amantadine and rimantadine against influenza A

: Amantadine and the analogue rimantadine have an antiviral effect on influenza A virus and are approximately 60% effective in preventing illness. The drugs are administered orally, and peak plasma concentration is achieved at two hours after a single dose. Side effects occur in 5-20% of the cases, but generally mild and transient and seen mainly with doses of more than 200 mg a day. This paper describes the mechanism of action and the pharmacokinetics of the drugs, and refers to some important clinical trials. Amantadine has been used in Norway to treat Parkinson's disease since 1972. The licensing of the amantadine and rimantadine for use against influenza A in this country is also discussed.