Side Effects and Safety
- Approximately 27.8 million Tamiflu prescriptions have been dispensed in the U.S. over the past 11 years.1
- Demonstrated safety profile in children (≥1 year of age), adults, and the elderly (>65 years of age).2
- In vitro studies showed no interference with the cytochrome P450 pathway.2
- Co-administration with amoxicillin does not alter plasma levels of either drug.2
Adverse Events Reported in Treatment and Prophylaxis Studies in Children Aged 1 to 12 Years
Most Frequent Adverse Events Occurring in Children Aged 1 to 12 Years in Studies in Naturally Acquired Influenza2
twice daily n=515
once daily n=99
|Asthma (including aggravated)||3%||4%||1%||1%|
- Adverse events included are all events reported in the treatment studies with frequency ≥1% in the Tamiflu 75-mg twice-daily group.
- The majority of subjects received placebo; 254 subjects from a randomized, open-label postexposure prophylaxis study in households did not receive placebo or prophylaxis therapy.
Prophylaxis Study in Immunocompromised Subjects
In a 12-week seasonal prophylaxis study in 475 immunocompromised subjects, including 18 pediatric subjects 1 to 12 years of age, the safety profile in the 238 subjects receiving Tamiflu was consistent with that previously observed in other Tamiflu prophylaxis clinical trials.2
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.
- Data on file, Genentech USA, Inc.
- Tamiflu® (oseltamivir phosphate) Prescribing Information. South San Francisco, CA: Genentech USA, Inc.; January, 2013.
- Centers for Disease Control and Prevention. Influenza Antiviral Medications: Summary for Clinicians. http://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm. Updated September 4, 2014. Accessed October 2, 2014.