Zanamivir and oseltamivir: two new options for the treatment and prevention of influenza.
BACKGROUND
Influenza infection is responsible for thousands of hospitalizations and deaths in the United States each year. Until recently, management options were limited to vaccination or use of the antiviral agents amantadine and rimantadine. Two antiviral drugs, zanamivir and oseltamivir, have recently been approved by the US Food and Drug Administration for the treatment of influenza A and influenza B.


OBJECTIVE
This article reviews the published data on the pharmacology and clinical utility of zanamivir and oseltamivir in the treatment and prevention of influenza A and influenza B illness.


METHODS
To identify relevant literature, a search of MEDLINE, International Pharmaceutical Abstracts, and the Iowa Drug Information Service was conducted for the period from 1969 to 2000. The search terms used were influenza, neuraminidase, zanamivir, oseltamivir; amantadine, and rimantadine. The reference lists of the articles so obtained were used to identify additional publications.


RESULTS
Zanamivir and oseltamivir inactivate viral neuraminidase, an enzyme responsible for cleaving sialic acid residues on newly formed virions as they bud off from the host cell. This inhibition results in aggregation of virions on the surface of the host cell, which limits the extent of infection and speeds recovery from illness. Clinical studies have shown that neuraminidase inhibitors can decrease the median duration of influenza-related symptoms by approximately 1 day if initiated within 48 hours of the onset of symptoms of influenza.


CONCLUSIONS
Evidence supports the use of zanamivir and oseltamivir in the treatment of influenza; however, additional studies are needed to clarify their utility and tolerability in pediatric and high-risk patients, as well as their utility in the prevention of influenza.
Dreitlein
W B
WB
College of Pharmacy and Allied Health Professions, St. John's University, Jamaica, New York 11439, USA. dreitlew@stjohns.edu
Maratos
J
J
Brocavich
J
J
D000081:Acetamides / Q000009:adverse effects / Q000627:therapeutic use*; D000818:Animals; D000998:Antiviral Agents / Q000627:therapeutic use*; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D006146:Guanidines; D006801:Humans; D007251:Influenza, Human / Q000188:drug therapy* / Q000517:prevention & control; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D053139:Oseltamivir; D011714:Pyrans; D012794:Sialic Acids / Q000009:adverse effects / Q000627:therapeutic use*; D053243:Zanamivir
D000081:Acetamides; D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; D053139:Oseltamivir; D009439:Neuraminidase; D053243:Zanamivir