You should talk with your healthcare provider prior to taking this drug if you have:
- Seizures or epilepsy
- Liver disease, such as liver failure, cirrhosis, or hepatitis
- Kidney disease, including kidney failure (renal failure)
- Any allergies, including allergies to food, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant (see Flumadine and Pregnancy)
- Breastfeeding (see Flumadine and Breastfeeding).
Make sure to tell your healthcare provider about all other medicines you are taking, including prescription and nonprescription medications, vitamins, and herbal supplements.
(Click Precautions and Warnings With Rimantadine to learn more, including information on who should not take the drug.)
It is thought that rimantadine works by inhibiting the uncoating of the flu virus, an important step in the replication (the "reproduction") of the virus. Specifically, rimantadine inhibits the activity of the influenza virus M2 protein, which forms a channel in the virus membrane. As a result, the virus cannot replicate (make copies of itself) after it enters a human cell.
Rimantadine is effective only for some influenza A viruses and is not effective against influenza B viruses. Since the "bird flu" or "avian flu" virus (H5N1) is a type of influenza A, it is possible that rimantadine may work for some strains of this virus. However, many strains of H5N1 influenza are resistant to rimantadine.
For any given year, the predominant flu strain may or may not be susceptible to rimantadine. If the predominant flu strain is not susceptible to rimantadine, this medication should not be used to prevent or treat the flu.