Clinical Overview of Influenza
In all patients, the flu can take its toll.
- On average, influenza affects an estimated 5 to 20 percent (16-63 million) of the United States population annually.1,2
The severity of influenza is unpredictable and often underestimated.
- The annual range of deaths associated with seasonal influenza spans 3,000 to 49,000 (1976-2007).3
- Approximately 90% of influenza-associated deaths occur among adults aged ≥65 years.3
Flu is a major cause of hospitalization.
Symptoms of influenza
Influenza is spread from person to person through respiratory droplets that are dispersed when an infected person coughs or sneezes in close proximity to someone who is not infected.1
Adults can be infectious from 1 day before onset of symptoms to 5-7 days after illness onset.6
- Sore throat
- Chest discomfort, cough
- Some people may have vomiting and diarrhea, though this is more common in children than adults
- Most people who get influenza will recover in a few days to less than 2 weeks8
Tamiflu is indicated for the treatment of acute, uncomplicated illness due to influenza infection in patients 2 weeks of age and older who have been symptomatic for no more than 2 days. Tamiflu is also indicated for the prophylaxis of influenza in patients 1 year and older
- Efficacy of Tamiflu in patients who begin treatment after 48 hours of symptoms has not been established
- Tamiflu is not a substitute for early and annual influenza vaccination
- There is no evidence for efficacy of Tamiflu in any illness caused by agents other than influenza viruses types A and B
- Influenza viruses change over time. Emergence of resistance mutations could decrease drug effectiveness. Prescribers should consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use Tamiflu
Serious Skin/Hypersensitivity Reactions
- Tamiflu is contraindicated in patients who have had severe allergic reactions such as anaphylaxis or serious skin reactions such as toxic epidermal necrolysis, Stevens-Johnson syndrome, and erythema multiforme to any component of Tamiflu
- In postmarketing experience, cases of anaphylaxis and serious skin reactions, including toxic epidermal necrolysis, Stevens-Johnson syndrome and erythema multiforme, have been reported with Tamiflu. Tamiflu should be stopped and appropriate treatment instituted if an allergic-like reaction occurs or is suspected
- Influenza can be associated with a variety of neurologic and behavioral symptoms, which can include events such as hallucinations, delirium and abnormal behavior, in some cases resulting in fatal outcomes. These events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease
- Closely monitor patients with influenza for signs of abnormal behavior. If neuropsychiatric symptoms occur, evaluate the risks and benefits of continuing treatment for each patient
- Serious bacterial infections may begin with influenza-like symptoms or may coexist with or occur as complications during the course of influenza. Tamiflu has not been shown to prevent such complications
Limitations of Populations Studied
- Efficacy of Tamiflu in the treatment of influenza in patients with chronic cardiac disease and/or respiratory disease has not been established. No information is available regarding treatment of influenza in patients with any medical condition sufficiently severe or unstable to be considered at imminent risk of requiring hospitalization
- Efficacy of Tamiflu for treatment or prophylaxis of influenza has not been established in immunocompromised patients
Concurrent Use with Live Attenuated Influenza Vaccine
- The concurrent use of Tamiflu with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. However, because of the potential for interference between these products, LAIV should not be administered within 2 weeks before or 48 hours after administration of Tamiflu, unless medically indicated
Most Common Adverse Reactions
- Adverse events that occurred more frequently in patients treated with Tamiflu than in patients taking placebo (frequency ≥ 2%) across clinical trials were nausea, vomiting, abdominal pain, ear disorder, and diarrhea
- The safety profile observed in pediatric patients 2 weeks to less than 1 year of age was consistent with the established safety profile of subjects aged 1 year and above, with vomiting, diarrhea and diaper rash being the most frequently reported adverse reactions
For additional important safety information, please see Tamiflu full prescribing information at www.tamiflu.com.
You are encouraged to report side effects to Genentech by calling 1-888-835-2555 or to the FDA by visiting www.fda.gov/medwatch or calling 1-800-FDA-1088.
- Centers for Disease Control and Prevention. Seasonal Influenza Q&A. http://www.cdc.gov/flu/about/qa/disease.htm. Updated August 14, 2014. Accessed October 2, 2014.
- US Census Bureau. U.S. and World Population Clock. http://www.census.gov/popclock/. Accessed October 2, 2014.
- Centers for Disease Control and Prevention. Estimates of deaths associated with seasonal influenza — United States, 1976-2007. MMWR. 2010:59(33);1057-1062. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5933a1.htm. Updated August 27, 2010. Accessed October 2, 2014.
- Centers for Disease Control and Prevention. Seasonal Influenza-Associated Hospitalizations in the United States: Questions & Answers. http://www.cdc.gov/flu/about/qa/hospital.htm. Updated June 24, 2011. Accessed October 2, 2014.
- Atkinson W, Wolfe C, Hamborsky J, McIntyre L, Wolfe S, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases. 12th ed., second printing. Washington, DC: Public Health Foundation; 2009:135-154. http://www.cdc.gov/vaccines/pubs/pinkbook/index.html. Updated July 25, 2014. Accessed October 2, 2014.
- Centers for Disease Control and Prevention. Key Facts about Influenza (Flu) & Flu Vaccine. http://www.cdc.gov/flu/keyfacts.htm. Updated September 9, 2014. Accessed October 9, 2014.
- National Institute of Allergy and Infectious Diseases. Is It a Cold or the Flu? http://www.niaid.nih.gov/topics/Flu/Documents/sick.pdf. Updated August 2014. Accessed October 2, 2014.
- Centers for Disease Control and Prevention. Flu Symptoms & Severity. http://www.cdc.gov/flu/about/disease/symptoms.htm. Updated August 13, 2014. Accessed October 8, 2014.
- Hayden FG, Belshe R, Villanueva C, et al. Management of influenza in households: a prospective, randomized comparison of oseltamivir treatment with or without postexposure prophylaxis. J Infect Dis. 2004;189:440-449.
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