Influenza
NB: It is essential to check resistance patterns of the current season’s influenza strains.
Amantadine is active against susceptible Influenza A (not active against Influenza B).
Oseltamivir and zanamivir are active against susceptible Influenza A and B.
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Antiviral prophylaxis indicated:
for control of Influenza outbreaks among high risk residents of institutions
as an adjunct to late vaccination of people at high risk
as sole agent for prophylaxis during an influenza outbreak in high risk individuals where vaccination cannot be given
as a supplement to vaccination in high risk individuals with impaired immune response to the vaccine
for unvaccinated persons who provide hands on patient care for high risk individuals during an outbreak.
Duration of antiviral prophylaxis is 10 days, or duration of outbreak, whichever is longer.
NB: Antiviral prophylaxis should NOT replace annual influenza vaccination.
Oseltamivir
| Age | Weight/Creatinine Clearance | Dosage |
|---|---|---|
| 1-12 years | ≤ 15kg | 30mg PO daily |
| > 15-23kg | 45 mg PO daily | |
| > 23-40kg | 60mg PO daily | |
| > 40kg | 75mg PO daily | |
| ≥ 13 years | > 60 mL/min | 75mg PO daily |
| > 30-60mL/min | 30mg PO daily | |
| 10-30 mL/min | 30mg PO q2days |
Zanamivir
| Age | Dosage |
|---|---|
| ≥ 7 years | 10mg inhaled by mouth daily |
Amantadine
No Renal Impairment
| Age | Dosage |
|---|---|
| 1-9 years | 5mg/kg divided once or twice daily (max daily dose 150mg) |
| 10-64 years | 200mg divided once or twice daily |
| ≥ 65 years | 100mg once daily |
Renal Impairment
| Creatinine clearance (mL/min/1.73m²) | Dosage with capsules | Daily dosage with solution (10mg/mL) | |
|---|---|---|---|
| 10-64 years old | > 65 years old | > 65 years old | |
≥ 80 |
100mg twice daily |
100mg once daily |
100mg (10mL) |
60-79 |
Alternating daily doses of 200mg and 100mg |
Alternating daily doses of 100mg and 50mg |
75mg (7.5mL) |
40-59 |
100mg once daily |
100mg every 2 days |
50mg (5mL) |
30-39 |
200mg twice weekly |
100mg twice weekly |
25mg (2.5mL) |
20-29 |
100mg three times/week |
50mg three times/week |
25mg (2.5mL) |
10-19 |
Alternating weekly doses of 200mg and 100mg |
Alternating weekly doses of 100mg and 50mg |
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