Amantadine and its analogue rimantadine are primary amines with a large carbon ring. Their exact mechanism of action as antiviral drug is unknown. Amantadine inhibits an early step in viral replication: penetration of the virus into the host cell. It also prevents the uncoating of the virus, thereby inhibiting the release of viral genetic material. Secondly, amantadine might also interfere with the last step in the replication cycle, thereby inhibiting viral assembly.
Amantadine is well absorbed orally and has a large volume of distribution. The drug is excreted largely unchanged in urine. Common side effects include gastrointestinal problems and CNS complaints. High doses can be neurotoxic and result in seizures or coma.
Amantidine is effective as therapy and prophylaxis against influenza A and B strains.
Extra info: Amantadine is only effective against influenza A.
Amantidine has relevant pharmacotherapeutic effects in Parkinson's disease.
Extra info: Due to the effects of amantadine on the CNS, it is sometimes used as adjunctive therapy in Parkinson’s disease and can cause significant CNS side effects.