| Indication |
For the prevention and treatment of influenza A and B. |
| Pharmacodynamics |
Zanamivir, an antiviral agent, is a neuraminidase inhibitor
indicated for treatment of uncomplicated acute illness due to influenza A
and B virus in adults and pediatric patients 7 years and older who have
been symptomatic for no more than 2 days. Zanamivir has also been shown
to significantly inhibit the human sialidases NEU3 and NEU2 in the
micromolar range (Ki 3.7 +/-0.48 and 12.9+/-0.07 microM, respectively),
which could account for some of the rare side effects of zanamivir. |
| Mechanism of action |
The proposed mechanism of action of zanamivir is via inhibition of
influenza virus neuraminidase with the possibility of alteration of
virus particle aggregation and release. By binding and inhibiting the
neuraminidase protein, the drug renders the influenza virus unable to
escape its host cell and infect others. |
| Absorption |
Absolute bioavailability is very low following oral administration
(2%). Following oral inhalation, bioavailability is 4% to 17%. |
| Volume of distribution |
Not Available |
| Protein binding |
Zanamivir has limited plasma protein binding (<10%). |
| Metabolism |
Not metabolized |
| Route of elimination |
It is excreted unchanged in the urine with excretion of a single dose completed within 24 hours.
Unabsorbed drug is excreted in the feces.Zanamivir is renally excreted as unchanged drug. |
| Half life |
2.5-5.1 hours |
| Clearance |
- 2.5 – 10.9 L/h [Following oral inhalation 10 mg]
- 5.3 L/h [Normal renal function receiving IV single dose of 4 mg or 2 mg]
- 2.7 L/h [Patients with mild and moderate renal impairement receiving IV single dose of 4 mg or 2 mg]
- 0.8 L/h [Patients with severe renal impairement receiving IV single dose of 4 mg or 2 mg]
|
| Toxicity |
Not Available |
