Antivirals used for treatment of Respiratory viruses

There are a number of viruses that cause respiratory tract infections. The majority of infections do not require treatments. Some of the infection can result in severe illnesses in some group of patients, for instance in preterm babies or immunocompromised patients. In the elderly population, infections with influenza is known to cause high fatalities. Antivirals is believed to reduce the severity of illness, and shorten the duration of illness. It can also prevent loss of life.

 

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Influenza A

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Oseltamivir

For treatment-75mg twice daily for 5 days

For prevention- 75mg once daily for at least 7 days

 

Zanamivir

For treatment- 10 mg twice daily for 5 days

Not licensed for prophylaxis. 

 

Amantadine

For treatment- 100 mg daily for 5 days

For prevention- 100 mg daily for up to 6 weeks

 

The use of antiviral drugs is recommended for

Ø      Elderly patients presented within 48 hours of infections.

Ø      Immunocompromised patients

Ø      Patients with severe illness

 

Prophylaxis is only given to patients that have risk factor to develop severe infections if they have not been vaccinated for influenza strains that circulate at that particular season.

Vaccination should be offered with antivirals as prophylaxis.

 

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Influenza B

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Oseltamivir

For treatment-75mg twice daily for 5 days

For prevention- 75mg once daily for at least 7 days

 

Zanamivir

 For treatment- 10 mg twice daily for 5 days

It is not licensed for prophylaxis.

 

Treatment with antivirals is recommended for

      Ø      Elderly patients who present within 48 hours of infections.

Ø      Immunocompromised patients

Ø      Patients with severe illness

 

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 Non- Flu ( RSV, Parainfluenza, Adenovirus)

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Ribavirin

Inhalation or nebulisation.

20mg/ml solution for 12 to 18 hours for 3 to 5days

 

The indications to treat patients include

Ø       moderate to severe bronchiolitis

Ø      If the patient is immunocompromised.

Ø      Severe infection with RSV, Parainfluenza or Adenoviruses

 

 

For Adenovirus Cidofovir or Ribavirin can be used.

Indications

• Severe infection (disseminated infection involving more than one organ)
• Immunocompromised patients

 

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 SARS

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There is no effective antiviral; however, there is only one anecdotal report that showed retrospectively that some patients on  a protease inhibitor for HIV infections were benefited. As there is no any antiviral considered to be effective, it is not unreasonable to advise Lopinavir to treat patients infected with SARS.

Lopinavir

Dose

 

v     400mg with 100mg of ritonavir twice daily

 

 

Ribavirin

Given by inhalation or nebulisation

20mg/ml solution for 12 to 18 hours for 3 to 5days

 

NB: There is no proper clinical trial however the above two drugs may have potential benefit.