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Rimantadine

Rimantadine is a synthetic anti-viral drug that can prevent viruses in cells from multiplying. To prevent a viral infection, the drug should be started before exposure to the virus. Clearly, this is not practical for most viral infections. Rimantadine initially was used to prevent influenza A during flu season, and, if given within 24 to 48 hours after the onset of flu symptoms, to decrease the severity of the flu. Rimantadine is chemically related to amantadine (Symmetrel), but rimantadine has fewer side effects on the nervous system than amantadine. Rimantadine was approved for use in 1993.

Rimantadine is used for the prevention or treatment of infections with influenza A virus, especially for individuals at high-risk such as immunosuppressed patients and nursing home residents. It should not be used as a substitute for vaccination.

Rimantadine is taken once or twice daily with or without food. If it causes an upset stomach, it can be taken with food. If used for treatment of an established infection, rimantadine should be started as soon as possible, preferably within 48 hours after the onset of the symptoms of infection with influenza A. It should be continued for 5 to 7 days or for 24 to 48 hours after the disappearance of symptoms.

The risk of side effects with rimantadine is less than 3% or 1 in 30 patients who are treated. The most common side effects are nausea, vomiting, sleep disturbances, dizziness, loss of appetite, and dry mouth.