Influenza: Treatment & Medication

Author: Hakan Leblebicioglu, MD, Chairman, Professor, Department of Infectious Diseases and Clinical Microbiology, Ondokuz Mayis University Medical School, Turkey
Coauthor(s): Itzhak Brook, MD, MSc, Professor, Department of Pediatrics, Georgetown University School of Medicine
Contributor Information and Disclosures

Updated: Apr 27, 2009

Medical Care
Influenza symptoms may last longer than 1 week. Caregivers can relieve and soothe children's aches and pains with basic supportive care.

Acetaminophen (paracetamol/panadol) may be administered for fever and relief of other symptomatology.
Caution: In children <16 y who have symptoms of influenza infection or colds, aspirin is not recommended because of an association with Reye syndrome.
Use cough suppressants and expectorants to treat the cough. Steam inhalations may also be useful. If dehydration occurs, administration of oral or intravenous fluids is indicated.

Diet
No special diet is indicated for influenza.

Activity
Adequate rest is recommended.

Medication
The following 4 antiviral agents are approved for preventing or treating influenza: amantadine, rimantadine, zanamivir, and oseltamivir.

Amantadine and rimantadine are effective against type A influenza virus only. They are approved by the US Food and Drug Administration (FDA) for influenza type A prophylaxis in patients older than 1 year. Amantadine is also FDA-approved for treatment in children.
Since the 2005-2006 influenza season, amantadine and rimantadine are no longer recommended by the CDC because of resistance. Laboratory testing by the CDC on the predominant strain of influenza (H3N2) currently circulating in the United States shows that it is resistant to these drugs.

Zanamivir and oseltamivir (Tamiflu) are members of a new class of drugs termed neuraminidase inhibitors and are active against both influenza virus type A and type B.
Zanamivir is provided as a dry powder that is administered by inhalation. It is approved for the treatment of uncomplicated acute influenza A or B in persons aged 7 years and older who have been symptomatic for no more than 2 days.
Oseltamivir is approved for oral administration in persons older than 1 year with influenza A or B who have been symptomatic for no more than 2 days.

Neither zanamivir nor oseltamivir is approved for prophylaxis of influenza infection.

Oseltamivir (Tamiflu) resistance has emerged in the United States during the 2008-2009 influenza season. The CDC has issued revised interim recommendations for antiviral treatment and prophylaxis of influenza.
Preliminary data from a limited number of states indicate a high prevalence of influenza A (H1N1) virus strains resistant to oseltamivir (Tamiflu). Because of this, zanamivir (Relenza) is recommended as the initial choice for antiviral prophylaxis or treatment when influenza A infection or exposure is suspected. A second-line alternative is a combination of oseltamivir plus rimantadine, rather than oseltamivir alone. Local influenza surveillance data and laboratory testing can assist the physician regarding antiviral agent choice.

Influenza A viruses, including two subtypes (H1N1) and (H3N2), and influenza B viruses currently circulate worldwide, but the prevalence of each can vary among communities and within a single community over the course of an influenza season.

In the United States, 4 prescription antiviral medications (oseltamivir, zanamivir, amantadine, rimantadine) are approved for treatment and chemoprophylaxis of influenza.
Since January 2006, the neuraminidase inhibitors (oseltamivir, zanamivir) have been the only recommended influenza antiviral drugs because of widespread resistance to the adamantanes (amantadine, rimantadine) among influenza A (H3N2) virus strains. The neuraminidase inhibitors have activity against influenza A and B viruses, whereas the adamantanes have activity against only influenza A viruses.

In 2007-2008, a significant increase in the prevalence of oseltamivir resistance was reported among influenza A (H1N1) viruses worldwide. During the 2007-2008 influenza season, 10.9% of H1N1 viruses tested in the United States were resistant to oseltamivir. Complete recommendations are available from the CDC.

Treatment of influenza A virus illness should be started as soon as possible, preferably within 24-48 hours after onset of signs and symptoms, and should be continued for 24-48 hours after the disappearance of signs and symptoms.

Antiviral agents
Use of influenza-specific antiviral drugs for chemoprophylaxis or treatment of influenza is an important adjunct to vaccine, particularly for controlling outbreaks in closed populations.