ALL ABOUT SWINEFLU..ANTIVIRAL AGENTS

Drugs indicated for treatment of H1N1 influenza A virus include neuraminidase inhibitors (ie, oseltamivir and zanamivir).
Oseltamivir (Tamiflu)
Oseltamivir inhibits neuraminidase, which is a glycoprotein on the surface of influenza virus that destroys an infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, this agent decreases the release of viruses from infected cells and, thus, viral spread. Oseltamivir is effective in the treatment of influenza A or B and must be administered within 48 hours of symptom onset to provide optimal treatment. The sooner the drug is administered after symptom onset, the better the likelihood of a good outcome. However, some studies of treatment of seasonal influenza have indicated benefit, including reductions in mortality or duration of hospitalization even for patients whose treatment was started more than 48 hours after illness onset.22 Oseltamivir reduces the length of illness by an average of 1.5 days. (In a subgroup of high-risk patients, illness was reduced by 2.5 d.) In addition, the severity of symptoms is also reduced.
Duration of administration for treatment is 5 days. Postexposure prophylaxis should be initiated within 7 d of exposure and continued for at least 10 days. Pre-exposure prophylaxis should be initiated during potential exposure period and continue for 10 days after last known exposure.22
Oseltamivir is available as 30-mg, 45-mg, and 75-mg oral capsules and as a powder for suspension that contains 12 mg/mL after reconstitution.
• Adult dose
o Treatment for acute illness: 75 mg PO bid for 5 d
o Prophylaxis: 75 mg PO qd (Please refer to duration of prophylaxis specific for postexposure.)
• Pediatric dose
o Treatment for acute illness and age <1 year
 <3 months: 12 mg PO bid for 5 d
 3-5 months: 20 mg PO bid for 5 d
 6-11 months: 25 mg PO bid for 5 d
o Treatment for acute illness and age >1 year
 <15 kg: 30 mg PO bid for 5 d
 15-23 kg: 45 mg PO bid for 5 d
 23-40 kg: 60 mg PO bid for 5 d
 >40 kg: Administer as in adults
o Prophylaxis and age <1 year
 <3 months: Data limited; not recommended unless situation judged critical
 3-5 months: 20 mg PO qd
 6-11 months: 25 mg PO qd
o Prophylaxis and age >1 year
 <15 kg: 30 mg PO qd
 15-23 kg: 45 mg PO qd
 23-40 kg: 60 mg PO qd
 >40 kg: Administer as in adults
Zanamivir (Relenza)
Zanamivir inhibits 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. Zanamivir is effective against both influenza A and B. The preparation of zanamivir is in powder form for inhalation via the Diskhaler oral inhalation device. Circular foil discs that contain 5-mg blisters of drug are inserted into the supplied inhalation device. Individuals with asthma or other respiratory conditions that may decrease ability to inhale drug should be given oseltamivir.
• Adult dose
o Treatment for acute illness: 10 mg inhaled orally bid for 5 d
o Prophylaxis of household contact: 10 mg inhaled orally qd for 10 d (initiate within 36 h)
o Prophylaxis for community outbreak: 10 mg inhaled orally qd for 28 d (initiate within 5 d of outbreak)
• Pediatric dose
o Treatment for acute illness
 <7 years: Not established
 >7 years: Administer as in adults
o Prophylaxis in household contact
 <5 years: Not established
 >5 years: Administer as in adults
o Prophylaxis in community outbreak
 Adolescents 12-16 years: Administer as in adults