Early treatment with the previously mentioned antivirals can shorten the duration of influenza symptoms by 1/2 day to 3 days and may reduce the risk of complications. The greatest clinical benefit is seen when antiviral treatment is initiated within 48 hours of illness onset. It is also important to correctly identify patients who meet parameters for either chemoprophylaxis or treatment so that they receive the correct dosage and duration of therapy.
Chemoprophylaxis should be considered in adults and children aged 1 year and older who are at high risk for developing influenza complications and for whom influenza vaccination is contraindicated, unavailable, or expected to have low effectiveness (e.g., significantly immunocompromised persons).[18,19] Chemoprophylaxis should also be considered in this population when the vaccination has not yet been administered and influenza has been detected within the community. Unvaccinated adults—including healthcare workers—and children aged ≥1 year who are in close contact with persons at high risk for developing influenza complications during periods of influenza activity should be considered for chemoprophylaxis, as should all vaccinated and unvaccinated persons in institutions experiencing influenza outbreaks.
Antiviral treatment should be initiated in all persons with laboratory-confirmed or highly suspected influenza virus infection, including those at high risk for developing complications (Table 2). Patients who require hospitalization for influenza regardless of vaccination status or underlying illness should also receive treatment. Outpatients at high risk for complications whose illness is not improving and who have a positive influenza test result may be candidates for influenza treatment. The same is true for outpatients who are not at increased risk, but wish to shorten the duration of illness or are in close contact with someone at high risk for complications secondary to influenza infection.
When the appropriate drug for chemoprophylaxis or treatment is being selected, local patterns of influenza circulation in the community throughout the influenza season should be considered. Oseltamivir (Tamiflu), zanamivir (Relenza), and peramivir (Rapivab) were the antivirals recommended for the 2016–2017 influenza season. A generic oseltamivir was approved by the FDA in August 2016, giving patients a less expensive option.
In patients who are mechanically ventilated or critically ill, oseltamivir may be administered via nasogastric or orogastric (NG/OG) tube. The powder from capsules should be dissolved in 20 mL of Sterile Water and injected down the NG/OG tube, followed by a 10-mL Sterile Water flush.
US Pharmacist. 2017;42(4):32-36. © 2017 Jobson Publishing