eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease
Influenza: Treatment & Medication
Updated: Aug 11, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
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 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.6
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 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.
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.
Amantadine (Symmetrel)
Prevents penetration of virus into host by inhibiting uncoating of influenza A. 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.
Adult
Prophylaxis or treatment:
200 mg/d PO in 1-2 divided doses
Pediatric
Prophylaxis or treatment:
<1 year: Not established
1-9 years: 5-9 mg/kg/d qd or divided bid; not to exceed 150 mg/d
10-12 years: 100-200 mg/d qd or divided bid
>12 years: Administer as in adults
Drugs with anticholinergic or CNS stimulant activity increase amantadine toxicity; concurrent administration of hydrochlorothiazide plus triamterene with amantadine may increase plasma concentrations of amantadine
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in liver disease, uncontrolled psychosis, eczematoid dermatitis, and seizures and in patients receiving CNS stimulant drugs; reduce dose in renal disease when treating Parkinson disease; do not discontinue abruptly
Rimantadine (Flumadine)
Inhibits viral replication of influenza A virus subtypes H1N1, H2N2, and H3N2. Prevents penetration of the virus into the host by inhibiting uncoating of influenza A. 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.
Adult
100 mg PO bid; decrease dose to 100 mg/d PO with severe renal or hepatic disease or in elderly persons
Pediatric
Prophylaxis or treatment:
<40 kg: 5 mg/kg/d PO; not to exceed 150 mg/d
>40 kg: Administer as in adults
Acetaminophen and aspirin reduce rimantadine levels when taken concurrently; cimetidine increases rimantadine plasma levels when taken concomitantly
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in hepatic impairment
Oseltamivir (Tamiflu)
Inhibitor of neuraminidase, which is a glycoprotein on the surface of the influenza virus that destroys the infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, release of viruses from infected cells and viral spread are decreased. Effective against influenza virus types A and B. Available as cap and an PO susp.
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 the prevalence of influenza A (H1N1) virus strains resistant to oseltamivir (Tamiflu) is high. 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.
Adult
Acute illness: 75 mg PO bid for 5 d
Prophylaxis: 75 mg/d PO for 10 d
Pediatric
Acute illness:
>1 year:
<15 kg: 2 mg/kg PO bid for 5 d; not to exceed 30 mg PO bid
15-23 kg: 45 mg PO bid for 5 d
24-40 kg: 60 mg PO bid for 5 d
>40 kg: Administer as in adults
Prophylaxis:
>1 year:
<15 kg: 30 mg PO qd for 10 d
15-23 kg: 45 mg PO qd for 10 d
24-40 kg: 60 mg PO qd for 10 d
>40 kg: Administer as in adults
Probenecid may decrease clearance
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in renal impairment (decrease dose if CrCl <30 mL/min), chronic cardiac or respiratory disease, and breastfeeding; may cause nausea or vomiting
Zanamivir (Relenza)
Inhibitor of neuraminidase, which is a glycoprotein on the surface of the influenza virus that destroys the infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, release of viruses from infected cells and viral spread are decreased. Effective against both influenza types A and B. To be inhaled through a Diskhaler PO inhalation device. Circular foil disks containing 5-mg blisters of drug are inserted into a supplied inhalation device.
Adult
Treatment: 2 inhalations (10 mg) PO bid for 5 d; initiate within 2 d of symptom onset
Prophylaxis: 2 inhalations (10 mg) PO qd for 10 d; initiate within 36 h of exposure
Note: One 5-mg blister per inhalation; 10-mg dose equals two 5-mg blisters
Pediatric
Treatment:
<7 years: Not established
>7 years: Administer as in adults
Prophylaxis:
<5 years: Not established
>5 years: Administer as in adults
None reported
Documented hypersensitivity; obstructive airway disease
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Monitor respiratory status; may cause bronchospasm; contraindicated with asthma or COPD; caution in breastfeeding
More on Influenza |
| Overview: Influenza |
| Differential Diagnoses & Workup: Influenza |
 Treatment & Medication: Influenza |
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References
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Further Reading
Keywords
influenza, flu, swine flu, swine influenza, H1N1, grip, grippe, acute catarrhal fever, respiratory infection, upper respiratory tract infection, viral infection, severe acute respiratory syndrome, SARS, pharyngitis, rhinitis, cervical lymphadenopathy, conjunctivitis, coup, pneumonia, chronic respiratory disease, chronic cardiac disease, chronic renal failure, diabetes mellitus, immunosuppression, treatment, diagnosis
