Prescribing Tamiflu

Administration and Storage of Tamiflu

Tamiflu is available in 75 mg, 45 mg, and 30 mg capsules and a liquid form for patients who may have difficulty swallowing capsules.1

Taking Tamiflu With Other Medications1

Information derived from pharmacology and pharmacokinetic studies of oseltamivir suggests that clinically significant drug interactions are unlikely.

Oseltamivir is extensively converted to oseltamivir carboxylate by esterases, located predominantly in the liver.

Drug interactions involving competition for esterases have not been extensively reported in literature. Low protein binding of oseltamivir and oseltamivir carboxylate suggests that the probability of drug displacement interactions is low.

The concurrent use of Tamiflu and live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. However, because of the possibility for interference between these products, LAIV should not be given within 2 weeks before or 48 hours after administration of Tamiflu, unless medically indicated. The concern about possible interference arises from the potential for antiviral drugs to inhibit replication of live virus. Trivalent inactivated influenza vaccine can be administered at any time relative to use of Tamiflu.1

Storing Tamiflu

Alternatively, store constituted liquid Tamiflu for up to 10 days at 77°F (25°C). As with all medications, keep out of the reach of children.1

Administering Tamiflu Liquid1

An oral dosing dispenser with 30 mg, 45 mg, and 60 mg graduations is provided with the oral suspension; the 75 mg dose can be measured using a combination of 30 mg and 45 mg.

Tamiflu can be mixed by a pharmacist extemporaneously when needed. Learn more about extemporaneous preparation.

Next Step: Learn about treating influenza in children with Tamiflu ›

Did you know?

The CDC recommends antivirals in addition to yearly vaccination and preventive measures as part of an effective influenza management plan.30,31

Indications

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 as recommended by the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices.
  • 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. Other factors (for example, changes in viral virulence) might also diminish clinical benefit of antiviral drugs. Prescribers should consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use Tamiflu.
Important Safety Information

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.

Neuropsychiatric Events

  • 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.
  • There have been postmarketing reports (mostly from Japan) of delirium and abnormal behavior leading to injury, and in some cases resulting in fatal outcomes, in patients with influenza who were receiving Tamiflu. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made but they appear to be uncommon based on Tamiflu usage data. These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution. The contribution of Tamiflu to these events has not been established. 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.

Bacterial Infections

  • 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 difference in the incidence of complications was observed between the treatment and placebo groups in this population. 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.
  • Safety and efficacy of Tamiflu for treatment of influenza in pediatric patients less than 2 weeks of age have not been established.
  • Safety and efficacy of Tamiflu for prophylaxis of influenza have not been established for pediatric patients less than 1 year of age.

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 and occurred in ≥2% of patients were (Tamiflu %, placebo %):
    • Treatment in adults (13 years of age and older)—nausea (10%, 6%), vomiting (9%, 3%)
    • Treatment in pediatrics (1-12 years of age)—vomiting (15%, 9%), abdominal pain (5%, 4%), ear disorder (2%, 1%)
    • Prophylaxis of adults (13 years of age and older)—nausea (7%, 3%), diarrhea (3%, 2%), vomiting (2%, 1%), abdominal pain (2%, 1%)
    • Prophylaxis of pediatrics (1-12 years of age)—vomiting (10%, 2%), abdominal pain (3%, 0%), nausea (4%, 1%)
  • 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

Please see the Tamiflu full Prescribing Information for complete safety information.

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.