 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  virus (influenza A). If you have been infected with the flu, this medication may help make your symptoms less severe and shorten the time it will take you to get better. Taking rimantadine if you have been or will be exposed to the flu may help to prevent you from getting the flu. This medication is an antiviral that is believed to work by stopping the growth of the flu virus. This medication is not a vaccine. To increase the chance that you will not get the flu, it is important to get a flu shot once a year at the beginning of every flu season, if possible.The Centers for Disease Control (CDC) recommends that rimantadine should not be used for the treatment or prevention of influenza A because the current influenza A virus in the United States is resistant to this medication. For more details, talk to your doctor or pharmacist. How to use Rimantadine HCL Take this medication by mouth with or without food as directed by your doctor. When this medication is taken to prevent flu, children younger than 10 should usually take it once a day, and children older than 10 and adults should take it twice a day. When used to treat flu in adults, the medication is taken twice a day. Do not increase </s>