EDCD Interim guideline on use of Oseltamivir (Tamiflu)

Oseltamivir (Tamiflu) is an antiviral drug, used to treat viral influenza and is also part of WHO essential drug. It is effective against H1N1 Influenza Type A as well as Type B virus.
Indication:
Acute and uncomplicated influenza in patients one year of age and older whose flu symptoms have not lasted more than 2 days. (And within 2 days of exposure in case of prophylaxis). It can be used for prophylaxis as well, but should be limited to high-risk groups (see below) or in case of an epidemic. It does not replace the use of influenza vaccine, but can cause less efficacy if used together. Healthy patients with uncomplicated illness need not be treated with Tamiflu.
On an individual patient basis, initial treatment decisions should be based on clinical assessment and knowledge about the presence of the virus in the community. Treatment decisions should not wait for laboratory confirmation of H1N1 infection.
Dosage and form:
ADULT:

• Influenza A and B Prophylaxis : 75 mg PO qDay for at least 10 days (For community outbreak, may administer for up to 6 weeks)
• Influenza A and B Treatment (Including Swine Flu) : 75 mg PO q12hr x5 days
• H1N1 Influenza A (Swine Flu) Prophylaxis: 75 mg PO qDay (Post-exposure prophylaxis: Initiate within 7 days of exposure and continue for at least 10 days, Pre-exposure prophylaxis (community outbreak): Initiate during potential exposure period and continue for 10 days after last known exposure)

Dosing Modifications
Renal impairment (CrCl 10-30 mL/min)

• Prophylaxis: 75 mg PO qOD, OR 30 mg PO qDay
• Treatment: 75 mg PO qDay x5 days

Renal impairment (CrCl <10 mL/min)

• Administer with caution

H1N1 Influenza A (Swine Flu) Treatment
Acute illness and age <1 year: Use only if critical, or benefit outweighs risk

• <3 months: 12 mg PO q12hr x5 days
• 3-5 months: 20 mg PO q12hr x5 days
• 6-11 months: 25 mg PO q12hr x5
  days

PEDIATRIC:
Influenza A and B Prophylaxis
<1 year: Safety and efficacy not established for prophylaxis
≥1 year:

• <15 kg: 30 mg PO qDay x10 days
• 15-23 kg: 45 mg PO qDay x10 days
• 23-40 kg: 60 mg PO qDay x10 days
• >40 kg: 75 mg PO qDay x10 days

Influenza A and B Treatment
<1 year: Safety and efficacy not established for treatment
≥1 year:

• <15 kg: 30 mg PO q12hr x5 days
• 15-23 kg: 45 mg PO q12hr x5 days
• 23-40 kg: 60 mg PO q12hr x5 days
• >40 kg: 75 mg PO q12hr x5 days

H1N1 Influenza A (Swine Flu) Prophylaxis
<1 year: Data limited; not recommended unless situation judged critical
≥1 year:

• <15 kg: 30 mg PO qDay x10 days
• 15-23 kg: 45 mg PO qDay x10 days
• 23-40 kg: 60 mg PO qDay x10 days
• >40 kg: Administer as in adults

H1N1 Influenza A (Swine Flu) Treatment
Acute illness and age <1 year: Use only if critical, or benefit outweighs risk

• <3 months: 12 mg PO q12hr x5 days
• 3-5 months: 20 mg PO q12hr x5 days
• 6-11 months: 25 mg PO q12hr x5 days

Acute illness and age ≥1 year:

• <15 kg: 30 mg PO q12hr x5 days
• 15-23 kg: 45 mg PO q12hr x5 days
• 23-40 kg: 60 mg PO q12hr x5 days
• >40 kg: Administer as in adults

Emergency preparation of oral suspension from 75 mg capsules

• Instructions below are for 100 mL of 6 mg/mL suspension
  1. Place 7 mL of distilled water into a polyethyleneterephthalate (PET) or glass bottle
  2. Empty content of eight 75-mg capsules (i.e., 600 mg) into bottle
  3. Gently swirl the suspension to ensure adequate wetting of the powder for at least 2 minutes
  4. Slowly add 91 mL of simple syrup
  5. Close bottle and shake well for about 30 minutes
• Instruct patient to shake well before use
• Stable for 5 days at room temperature or 5 weeks refrigerated at 2-8°C (36-46°F)

High-risk groups:

• Obese patients
• Elderly patients (>65 years age)
• Chronic kidney, heart, lungs, liver disease patients (use with caution)
• Malnourished children
• Pregnant women
• Immuno-compromised patients

Mechanism of action: Inhibits viral neuraminidases; stops release of virus from cells and prevents virus from crossing mucous lining of respiratory tract.
Interactions:  Tamiflu interacts with Clopidogrel (anti-platelet drug) and Probenecid (anti-gout drug), requiring close monitoring.
Adverse effects:  1-10% have reported nausea, vomiting, (most common) abdominal pain, conjunctivitis, ear disorder, epistaxis, insomnia, vertigo. Headache, renal and psychiatric syndromes have also been reported if used for prophylaxis.
Pregnancy category: C (Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.)
For queries, please contact:
Epidemiology and Disease Control Division (EDCD)

EDCD Interim guideline on use of Oseltamivir (Tamiflu)

Oseltamivir (Tamiflu) is an antiviral drug, used to treat viral influenza and is also part of WHO essential drug. It is effective against H1N1 Influenza Type A as well as Type B virus.