When do I need to take an antiviral?
The drugs work best when taken within one to two days after symptoms begin, but they can be used after that time frame and still work well, especially if you’re at higher risk of serious flu complications or are hospitalized with severe illness.
“The earlier you take them, the better the results,” says Andrew Pekosz, a flu researcher and professor of microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health.
To receive an antiviral prescription, you must have a positive flu test. Sometimes an at-home rapid test is enough, or you can get a test at your pharmacy or doctor’s office, Pekosz says.
Check with your pharmacy to see which antiviral options are in stock, he suggests. “That will make it easier for you to know which one you can go to if you need to fill your prescription quickly — and the earlier you take the antivirals, the better the outcome.”
Wondering when you can expect relief? According to the CDC, flu antivirals can shorten the time you’re sick by about one day.
Are some antivirals better for older adults than others?
All are effective, but baloxavir is the easiest to take, as it’s only one pill on the first day you feel ill, says Pekosz. That said, it does have some limitations.
For example, it shouldn’t be taken with dairy products, calcium-fortified beverages, laxatives, antacids or certain supplements [containing calcium, iron, magnesium, aluminum, selenium or zinc],” says Dr. Wilbur H. Chen, an infectious disease physician-scientist and professor at the University of Maryland School of Medicine.
Oseltamivir (oral) is most commonly recommended for older adults because of its proven efficacy, ease of use and longer safety track record, Rouphael notes.
Oseltamivir and peramivir are broken down in the kidneys, so people with kidney disease may require a smaller dose, Chen says.
Clinicians don’t recommend inhaled zanamivir for people with respiratory issues such as asthma or COPD. It also shouldn’t be used with a nebulizer or in people on ventilators, Chen adds.
“I don’t think one is necessarily better than another, so long as they can be given appropriately and in a timely manner,” Chen says.