Infectious Diseases I
Agent
Influenza
Activity
Bioavailability
Half-life
(hr)
Treatment
Dosage
Adverse
Effects
Comments
Zanamivir
Neuraminidase
inhibitor;
A and B
Inhaled: Up to
17%
2.5–5
10 mg twice a
day for 5 daysa
Allergic
reactions,
diarrhea,
nausea,
headache,
dizziness
Not
recommended
in patients
with chronic
lung disease
or severe
influenza;
not available
for delivery
through
mechanical
ventilator
circuit
because of
bronchospasm
Baloxavir
marboxil
Polymerase
acidic
endonuclease
inhibitor; A
and B
Tablet, oral:
Prodrug con-
verted almost
completely
to active
baloxavir;
bioavailability
not formally
established
79%
(53%–96%);
primary
hepatic
metabolism
(80% of
dose)
Weight 40–79.9
kg: 40 mg orally
once; weight ≥
80 kg: 80 mg
orally once
Generally
minimal (< 5%
of patients):
Diarrhea,
bronchitis,
nausea,
sinusitis,
headache
93% protein
binding;
limited data for
hospitalized
patients with
severe influenza
Amantadine
Adamantane;
A only
70%–100%
15–17
100 mg twice
a day
Nausea,
dizziness,
insomnia,
lower seizure
threshold,
anticholinergic
effects
High resistance
to current
influenza A
strains
Rimantadine
Adamantane;
A only
> 90%
24–35
100 mg twice
a day
Dizziness,
nausea,
vomiting;
anticholinergic
effects
High resistance
to current
influenza
A strains;
limited market
availability
aLonger durations of up to 14 days may be needed for severely ill patients.
IV = intravenous(ly); NG = nasogastric; OG = orogastric.
symptoms of infection. Development of oseltamivir resistance during therapy has been reported, but
this is rare. If suggested through local surveillance, therapy should be switched to zanamivir by the
appropriate administration route. Improvement in infectious and noninfectious complications may be
delayed, despite resolution of primary influenza infection. ARDS, in particular, may persist for days
beyond primary influenza.