| Item |
Information |
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Drug Groups
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approved; investigational |
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Description
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A guanido-neuraminic acid that is used to inhibit neuraminidase. [PubChem] |
| Indication |
For the prevention and treatment of influenza A and B. |
| Pharmacology |
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. |
| Affected Organisms |
| • |
Influenza A virus |
| • |
Influenza B virus |
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| Biotransformation |
Not metabolized |
| Absorption |
Absolute bioavailability is very low following oral administration (2%). Following oral inhalation, bioavailability is 4% to 17%. |
| Half Life |
2.5-5.1 hours |
| Protein Binding |
Zanamivir has limited plasma protein binding (<10%). |
| 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. |
| 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] |
| References |
| • |
Meindl P, Bodo G, Palese P, Schulman J, Tuppy H: Inhibition of neuraminidase activity by derivatives of 2-deoxy-2,3-dehydro-N-acetylneuraminic acid. Virology. 1974 Apr;58(2):457-63.
[Pubmed]
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| • |
von Itzstein M, Wu WY, Kok GB, Pegg MS, Dyason JC, Jin B, Van Phan T, Smythe ML, White HF, Oliver SW, et al.: Rational design of potent sialidase-based inhibitors of influenza virus replication. Nature. 1993 Jun 3;363(6428):418-23.
[Pubmed]
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| • |
Hata K, Koseki K, Yamaguchi K, Moriya S, Suzuki Y, Yingsakmongkon S, Hirai G, Sodeoka M, von Itzstein M, Miyagi T: Limited Inhibitory Effects of Oseltamivir and Zanamivir on Human Sialidases. Antimicrob Agents Chemother. 2008 Aug 11.
[Pubmed]
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Sugaya N, Tamura D, Yamazaki M, Ichikawa M, Kawakami C, Kawaoka Y, Mitamura K: Comparison of the clinical effectiveness of oseltamivir and zanamivir against influenza virus infection in children. Clin Infect Dis. 2008 Aug 1;47(3):339-45.
[Pubmed]
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