Tamiflu (oseltamivir phosphate): Uses, Dosage, Side Effects & Warnings

Uses

1 INDICATIONS AND USAGE TAMIFLU is an influenza neuraminidase inhibitor (NAI) indicated for: Treatment of acute, uncomplicated influenza A and B in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. ( 1.1 ) Prophylaxis of influenza A and B in patients 1 year and older. ( 1.2 ) Limitations of Use : Not a substitute for annual influenza vaccination. ( 1.3 ) Consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use. ( 1.3 ) Not recommended for patients with end-stage renal disease not undergoing dialysis. ( 1.3 ) 1.1 Treatment of Influenza TAMIFLU is indicated for the treatment of acute, uncomplicated illness due to influenza A and B infection in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. 1.2 Prophylaxis of Influenza TAMIFLU is indicated for the prophylaxis of influenza A and B in patients 1 year and older. 1.3 Limitations of Use TAMIFLU is not a substitute for early influenza vaccination on an annual basis as recommended by the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices. Influenza viruses change over time. Emergence of resistance substitutions 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 [see Microbiology (12.4) ] . TAMIFLU is not recommended for patients with end-stage renal disease not undergoing dialysis [see Dosage and Administration (2.4) and Use in Specific Populations (8.6) ].

Dosage and administration

Treatment of influenza Adults and adolescents (13 years and older): 75 mg twice daily for 5 days ( 2.2 ) Pediatric patients 1 to 12 years of age: Based on weight twice daily for 5 days ( 2.2 ) Pediatric patients 2 weeks to less than 1 year of age: 3mg/kg twice daily for 5 days ( 2.2 ) Renally impaired adult patients (creatinine clearance >30-60 mL/min): Reduce to 30 mg twice daily for 5 days ( 2.4 ) Renally impaired adult patients (creatinine clearance >10-30 mL/min): Reduce to 30 mg once daily for 5 days ( 2.4 ) ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after every hemodialysis cycle. Treatment duration not to exceed 5 days ( 2.4 ) ESRD patients on CAPD: Reduce to a single 30 mg dose immediately ( 2.4 ) Prophylaxis of influenza Adults and adolescents (13 years and older): 75 mg once daily for at least 10 days ( 2.3 ) - Community outbreak: 75 mg once daily for up to 6 weeks ( 2.3 ) Pediatric patients 1 to 12 years of age: Based on weight once daily for 10 days ( 2.3 ) - Community outbreak: Based on weight once daily for up to 6 weeks ( 2.3 ) Renally impaired adult patients (creatinine clearance >30-60 mL/min): Reduce to 30 mg once daily ( 2.4 ) Renally impaired adult patients (creatinine clearance >10-30 mL/min): Reduce to 30 mg once every other day ( 2.4 ) ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after alternate hemodialysis cycles for the recommended duration of prophylaxis ( 2.4 ) ESRD patients on CAPD: Reduce to 30 mg immediately and then 30 mg once weekly for the recommended duration of prophylaxis ( 2.4 ) 2.1 Dosage and Administration Overview Administer TAMIFLU for the treatment of influenza in patients 2 weeks of age or older [see Dosage and Administration (2.2) ] or for prophylaxis of influenza in patients 1 year and older [see Dosage and Administration (2.3) ] using: TAMIFLU capsules or TAMIFLU for oral suspension (supplied as a powder). This is the preferred formulation (6 mg per mL) for patients who cannot swallow capsules. Prior to use, the supplied TAMIFLU powder must be constituted with water by the pharmacist to produce the oral suspension [see Dosage and Administration (2.5) ]. The capsules and oral suspension may be taken with or without food; however, tolerability may be enhanced if TAMIFLU is taken with food. Adjust the TAMIFLU dosage in patients with moderate or severe renal impairment [see Dosage and Administration (2.4) ]. For patients who cannot swallow capsules, TAMIFLU for oral suspension is the preferred formulation. When TAMIFLU for oral suspension is not available from wholesaler or the manufacturer, TAMIFLU capsules may be opened and mixed with sweetened liquids such as regular or sugar-free chocolate syrup, corn syrup, caramel topping, or light brown sugar (dissolved in water). During emergency situations and when neither the oral suspension or the age-appropriate strengths of TAMIFLU capsules to mix with sweetened liquids are available, then a pharmacist may prepare an emergency supply of oral suspension from TAMIFLU 75 mg capsules [see Dosage and Administration (2.6) ]. 2.2 Recommended Dosage for Treatment of Influenza Initiate treatment with TAMIFLU within 48 hours of influenza symptom onset. Adults and Adolescents (13 years of age and older) The recommended oral dosage of TAMIFLU for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily (one 75 mg capsule or 12.5 mL of oral suspension twice daily) for 5 days. Pediatric Patients (2 weeks of age through 12 years of age) Table 1 displays the recommended oral dosage of TAMIFLU for treatment of influenza in pediatric patients 2 weeks of age through 12 years of age and provides information about prescribing the capsule or the formulation for oral suspension. 2.3 Recommended Dosage for Prophylaxis of Influenza Initiate post-exposure prophylaxis with TAMIFLU within 48 hours following close contact with an infected individual. Initiate seasonal prophylaxis with TAMIFLU during a community outbreak. Adults and Adolescents (13 years of age and older) The recommended dosage of TAMIFLU for prophylaxis of influenza in adults and adolescents 13 years and older is 75 mg orally once daily (one 75 mg capsule or 12.5 mL of oral suspension once daily) for at least 10 days following close contact with an infected individual and up to 6 weeks during a community outbreak. In immunocompromised patients, TAMIFLU may be continued for up to 12 weeks [see Use in Specific Populations (8.9) ] . The duration of protection lasts for as long as TAMIFLU dosing is continued. Pediatric Patients (1 year to 12 years of age) Table 1 displays the recommended oral dosage of TAMIFLU for prophylaxis of influenza in pediatric patients 1 year to 12 years of age based on body weight and provides information about prescribing the capsule or the formulation for oral suspension. Prophylaxis in pediatric patients is recommended for 10 days following close contact with an infected individual and up to 6 weeks during a community outbreak [see Use in Specific Populations (8.4) and Clinical Studies (14.2) ] . Table 1 TAMIFLU Dosage Recommendations in Pediatric Patients for Treatment and Prophylaxis of Influenza Weight Treatment Dosage for 5 days Prophylaxis Dosage for 10 days The recommended duration for post-exposure prophylaxis is 10 days and the recommended duration for community outbreak (seasonal/pre-exposure) prophylaxis is up to 6 weeks (or up to 12 weeks in immunocompromised patients). The amount supplied (e.g., number of bottles or capsules) for seasonal prophylaxis may be greater than for post-exposure prophylaxis. Volume of Oral Suspension (6 mg/mL) for each Dose Use an oral dosing dispensing device that measures the appropriate volume in mL with the oral suspension.

Dosage forms and strengths

Capsules: 30-mg (30 mg free base equivalent of the phosphate salt): light yellow, hard gelatin, with "ROCHE" printed in blue ink on the light yellow body and "30 mg" printed in blue ink on the light yellow cap. 45-mg (45 mg free base equivalent of the phosphate salt): grey, hard gelatin, with "ROCHE" printed in blue ink on the grey body and "45 mg" printed in blue ink on the grey cap. 75-mg (75 mg free base equivalent of the phosphate salt): grey/light yellow, hard gelatin, with "ROCHE" is printed in blue ink on the grey body and "75 mg" printed in blue ink on the light yellow cap. TAMIFLU for Oral Suspension: 6 mg per mL (final concentration when constituted) White powder blend for constitution. Capsules: 30 mg, 45 mg, 75 mg ( 3 ) For oral suspension: 360 mg oseltamivir base supplied as powder (constituted to a final concentration of 6 mg/mL) ( 3 )

Contraindications

4 CONTRAINDICATIONS TAMIFLU is contraindicated in patients with known serious hypersensitivity to oseltamivir or any component of the product. Severe allergic reactions have included anaphylaxis and serious skin reactions including toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme [see Warnings and Precautions (5.1) ] . Patients with known serious hypersensitivity to oseltamivir or any of the components of TAMIFLU ( 4 )

Warnings and precautions

Serious skin/hypersensitivity reactions such as Stevens-Johnson Syndrome, toxic epidermal necrolysis and erythema multiforme: Discontinue TAMIFLU and initiate appropriate treatment if allergic-like reactions occur or are suspected. ( 5.1 ) Neuropsychiatric events: Patients with influenza, including those receiving TAMIFLU, particularly pediatric patients, may be at an increased risk of confusion or abnormal behavior early in their illness. Monitor for signs of abnormal behavior. ( 5.2 ) 5.1 Serious Skin/Hypersensitivity Reactions Cases of anaphylaxis and serious skin reactions including toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme have been reported in postmarketing experience with TAMIFLU. Stop TAMIFLU and institute appropriate treatment if an allergic-like reaction occurs or is suspected. The use of TAMIFLU is contraindicated in patients with known serious hypersensitivity to TAMIFLU [see Contraindications (4) and Adverse Reactions (6.2) ] . 5.2 Neuropsychiatric Events There have been postmarketing reports of delirium and abnormal behavior leading to injury, and in some cases resulting in fatal outcomes, in patients with influenza who were receiving TAMIFLU [see Adverse Reactions (6.2) ] . 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. Influenza can be associated with a variety of neurologic and behavioral symptoms that 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 TAMIFLU-treated patients with influenza for signs of abnormal behavior. If neuropsychiatric symptoms occur, evaluate the risks and benefits of continuing TAMIFLU for each patient. 5.3 Risk of Bacterial Infections There is no evidence for efficacy of TAMIFLU in any illness caused by pathogens other than influenza viruses. 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. Prescribers should be alert to the potential for secondary bacterial infections and treat them as appropriate. 5.4 Fructose Intolerance in Patients with Hereditary Fructose Intolerance Fructose can be harmful to patients with hereditary fructose intolerance. One dose of 75 mg TAMIFLU for oral suspension delivers 2 grams of sorbitol. This is above the daily maximum limit of sorbitol for patients with hereditary fructose intolerance and may cause dyspepsia and diarrhea.

Side effects

The following serious adverse reactions are discussed below and elsewhere in the labeling: Serious skin and hypersensitivity reactions [see Warnings and Precautions (5.1) ] Neuropsychiatric events [see Warnings and Precautions (5.2) ] Most common adverse reactions (>1% and more common than with placebo): Treatment studies – Nausea, vomiting, headache. ( 6.1 ) Prophylaxis studies – Nausea, vomiting, headache, pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Genentech at 1-888-835-2555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adverse Reactions from Treatment and Prophylaxis Trials in Adult and Adolescent Subjects (13 years of age and older) The overall safety profile of TAMIFLU is based on data from 2,646 adult and adolescent subjects that received the recommended dosage of 75 mg orally twice daily for 5 days for treatment of influenza and 1,943 adult and adolescent subjects that received the recommended dosage of 75 mg orally once daily for up to 6 weeks for prophylaxis of influenza in clinical trials. The most common adverse reactions in the pooled treatment and pooled prophylaxis trials in adults and adolescents are displayed in Table 5 . The majority of these adverse reactions were reported on a single occasion, occurred on either the first or second treatment day and resolved spontaneously within 1-2 days. This summary includes otherwise healthy adults/adolescents and subjects "at risk" (subjects at higher risk of developing complications associated with influenza, e.g., elderly patients and patients with chronic cardiac or respiratory disease). In general, the safety profile in the subjects "at risk" was qualitatively similar to that in otherwise healthy adults/adolescents. Table 5 Adverse Reactions Occurring in ≥1% of Adults and Adolescents (13 years of age and older) in Treatment and Prophylaxis Trials Adverse reactions that occurred in ≥1% of TAMIFLU-treated adults and adolescents and ≥1% greater in TAMIFLU-treated subjects compared to placebo-treated subjects in either the treatment or prophylaxis trials. System Organ Class Treatment Trials Prophylaxis Trials Adverse Reaction TAMIFLU 75 mg twice daily (n = 2646) Placebo (n = 1977) TAMIFLU 75 mg once daily (n = 1943) Placebo (n = 1586) Gastrointestinal Disorders Nausea 10% 6% 8% 4% Vomiting 8% 3% 2% 1% Nervous System Disorders Headache 2% 1% 17% 16% General Disorders Pain <1% <1% 4% 3% Adverse Reactions from Treatment and Prophylaxis Trials in Pediatric Subjects (1 year to 12 years of age) A total of 1,481 pediatric subjects (including otherwise healthy pediatric subjects aged 1 year to 12 years and asthmatic pediatric subjects aged 6 to 12 years) participated in clinical trials of TAMIFLU for the treatment of influenza. A total of 859 pediatric subjects received treatment with TAMIFLU for oral suspension either at a 2 mg per kg twice daily for 5 days or weight-band dosing. Vomiting was the only adverse reaction reported at a frequency of > 1% in subjects receiving TAMIFLU (16%) compared to placebo (8%). Amongst the 148 pediatric subjects aged 1 year to 12 years who received TAMIFLU at doses of 30 to 60 mg once daily for 10 days in a post-exposure prophylaxis study in household contacts (n = 99), and in a separate 6–week seasonal influenza prophylaxis safety study (n = 49), vomiting was the most frequent adverse reaction (8% on TAMIFLU versus 2% in the no prophylaxis group). Adverse Reactions from Treatment Trials in Pediatric Subjects (2 weeks to less than 1 year of age) Assessment of adverse reactions in pediatric subjects 2 weeks to less than 1 year of age was based on two open-label studies that included safety data on 135 influenza-infected subjects 2 weeks to less than 1 year of age (including premature infants at least 36 weeks post conceptional age) exposed to TAMIFLU at doses ranging from 2 to 3.5 mg per kg of the formulation for oral suspension twice daily orally for 5 days. The safety profile of TAMIFLU was similar across the age range studied, with vomiting (9%), diarrhea (7%) and diaper rash (7%) being the most frequently reported adverse reactions, and was generally comparable to that observed in older pediatric and adult subjects. Adverse Reactions from the Prophylaxis Trial in Immunocompromised Subjects In a 12-week seasonal prophylaxis study in 475 immunocompromised subjects, including 18 pediatric subjects 1 year to 12 years of age, the safety profile in the 238 subjects receiving TAMIFLU 75 mg once daily was consistent with that previously observed in other TAMIFLU prophylaxis clinical trials [see Clinical Studies (14.2) ] . 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of TAMIFLU. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to TAMIFLU exposure.

Drug interactions

Live attenuated influenza vaccine (LAIV), intranasal: Avoid administration of LAIV within 2 weeks before or 48 hours after TAMIFLU use, unless medically indicated. ( 7 ) 7.1 Influenza Vaccines 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 TAMIFLU to inhibit replication of live vaccine virus and possibly reduce the efficacy of LAIV, avoid administration of LAIV within 2 weeks before or 48 hours after TAMIFLU administration, unless medically indicated. Inactivated Influenza Vaccine Inactivated influenza vaccine can be administered at any time relative to use of TAMIFLU. 7.2 Drugs Without Clinically Significant Drug Interaction with TAMIFLU No dose adjustments are needed for either oseltamivir or the concomitant drug when coadministering oseltamivir with amoxicillin, acetaminophen, aspirin, cimetidine, antacids (magnesium and aluminum hydroxides and calcium carbonates), rimantadine, amantadine, or warfarin [see Clinical Pharmacology (12.3) ] .

Use in specific populations

8.1 Pregnancy Risk Summary There are no adequate and well-controlled studies with TAMIFLU in pregnant women to inform a drug-associated risk of adverse developmental outcomes. Available published epidemiological data suggest that TAMIFLU, taken in any trimester, is not associated with an increased risk of birth defects. However, these studies individually are limited by small sample sizes, use of different comparison groups, and some lacked information on dose, which preclude a definitive assessment of the risk [see Data and Clinical Pharmacology (12.3) ] . In animal reproduction studies with oseltamivir, no adverse developmental effects were observed at clinically relevant exposures (see Data ) . The background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage is 2-4% and 15-20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Pregnant women are at higher risk of severe complications from influenza, which may lead to adverse pregnancy and/or fetal outcomes including maternal death, still births, birth defects, preterm delivery, low birth weight and small for gestational age. Data Human Data Published prospective and retrospective observational studies of more than 5,000 women exposed to TAMIFLU during pregnancy, including more than 1,000 women exposed in the first trimester, suggest that the observed rate of congenital malformations was not increased above the rate in the general comparison population, regardless of when therapy was administered during the gestational period. However, individually, none of these studies had adequate sample sizes and some lacked information on dose, which preclude a definitive assessment of the risk. Animal Data Oseltamivir was administered orally during organogenesis to pregnant rats (at 50, 250, or 1500 mg/kg/day on gestation days 6 to 17) and rabbits (at 50, 150, or 500 mg/kg/day on gestation days 6 to 18). In rats, embryo-fetal effects consisting of an increased incidence of minor skeletal malformations were observed at a maternally toxic dose (1500 mg/kg/day), resulting in systemic drug exposures (based on AUC for oseltamivir carboxylate) 190 times human exposures at the maximum recommended human dose (MRHD) of TAMIFLU (75 mg twice a day). In the rabbit study, embryo-fetal effects consisting of an increased incidence of minor skeletal abnormalities and variants were observed at maternally toxic doses (≥150 mg/kg/day) resulting in systemic exposures (based on AUC for oseltamivir carboxylate) ≥8 times human exposures at the MRHD of TAMIFLU. In prenatal and postnatal development studies in rats, oseltamivir was administered orally (at 50, 250, 500, or 1500 mg/kg/day) from organogenesis through late gestation, delivery, and lactation (gestation day 6 to postpartum/lactation day 20). Prolonged parturition duration and reduced offspring viability were observed at a maternally toxic dose (1500 mg/kg/day). No adverse maternal or offspring effects were observed at doses ≤500 mg/kg/day, resulting in systemic drug exposures (based on AUC for oseltamivir carboxylate) 44 times human exposures at the MRHD of TAMIFLU. 8.2 Lactation Risk Summary Based on limited published data, oseltamivir and oseltamivir carboxylate have been shown to be present in human milk at low levels considered unlikely to lead to toxicity in the breastfed infant. Postmarketing experience has not reported any information to suggest serious adverse effects of oseltamivir exposure via breast milk in infants. It is not known if oseltamivir affects human milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for TAMIFLU and any potential adverse effects on the breastfed child from the drug or from the underlying maternal condition. 8.4 Pediatric Use Treatment of Influenza The safety and efficacy of TAMIFLU for the treatment of influenza in pediatric patients 2 weeks old to 17 years of age has been established [see Dosage and Administration (2.2) , Clinical Pharmacology (12.3) , and Clinical Studies (14.1) ] and is based on: 13 to 17 years of age: Safety and efficacy in adolescent patients 13 to 17 years of age was supported by adequate and well-controlled trials in adults and adolescents and younger pediatric patients and safety data in adolescents treated with TAMIFLU in a study of treatment and prophylaxis. 1 year to 12 years of age: Safety and efficacy in pediatric patients 1 year to 12 years of age was supported by results of one double-blind, placebo-controlled trial in 452 pediatric patients with influenza in whom TAMIFLU 2 mg per kg twice daily or placebo was administered within 48 hours of symptom onset [see Clinical Studies (14.1) ]. Additional safety information was provided in a double-blind, placebo-controlled trial in pediatric patients 6 to 12 years of age with known asthma. Efficacy could not be established in pediatric patients with asthma. 2 weeks to less than 1 year of age: Safety and efficacy in pediatric patients 2 weeks to less than 1 year of age is supported by adequate and well-controlled trials in adults and older pediatric patients and two open-label trials of TAMIFLU (2 to 3.5 mg per kg twice daily for 5 days) in 136 pediatric subjects 2 weeks to less than 1 year of age. In these two trials, the oseltamivir plasma concentrations in these subjects were similar to or higher than the oseltamivir plasma concentrations observed in older pediatric subjects and adults [see Clinical Pharmacology (12.3) and Clinical Studies (14.1) ] . The safety and efficacy of TAMIFLU for treatment of influenza in pediatric patients less than 2 weeks of age have not been established.

Pregnancy

8.1 Pregnancy Risk Summary There are no adequate and well-controlled studies with TAMIFLU in pregnant women to inform a drug-associated risk of adverse developmental outcomes. Available published epidemiological data suggest that TAMIFLU, taken in any trimester, is not associated with an increased risk of birth defects. However, these studies individually are limited by small sample sizes, use of different comparison groups, and some lacked information on dose, which preclude a definitive assessment of the risk [see Data and Clinical Pharmacology (12.3) ] . In animal reproduction studies with oseltamivir, no adverse developmental effects were observed at clinically relevant exposures (see Data ) . The background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage is 2-4% and 15-20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Pregnant women are at higher risk of severe complications from influenza, which may lead to adverse pregnancy and/or fetal outcomes including maternal death, still births, birth defects, preterm delivery, low birth weight and small for gestational age. Data Human Data Published prospective and retrospective observational studies of more than 5,000 women exposed to TAMIFLU during pregnancy, including more than 1,000 women exposed in the first trimester, suggest that the observed rate of congenital malformations was not increased above the rate in the general comparison population, regardless of when therapy was administered during the gestational period. However, individually, none of these studies had adequate sample sizes and some lacked information on dose, which preclude a definitive assessment of the risk. Animal Data Oseltamivir was administered orally during organogenesis to pregnant rats (at 50, 250, or 1500 mg/kg/day on gestation days 6 to 17) and rabbits (at 50, 150, or 500 mg/kg/day on gestation days 6 to 18). In rats, embryo-fetal effects consisting of an increased incidence of minor skeletal malformations were observed at a maternally toxic dose (1500 mg/kg/day), resulting in systemic drug exposures (based on AUC for oseltamivir carboxylate) 190 times human exposures at the maximum recommended human dose (MRHD) of TAMIFLU (75 mg twice a day). In the rabbit study, embryo-fetal effects consisting of an increased incidence of minor skeletal abnormalities and variants were observed at maternally toxic doses (≥150 mg/kg/day) resulting in systemic exposures (based on AUC for oseltamivir carboxylate) ≥8 times human exposures at the MRHD of TAMIFLU. In prenatal and postnatal development studies in rats, oseltamivir was administered orally (at 50, 250, 500, or 1500 mg/kg/day) from organogenesis through late gestation, delivery, and lactation (gestation day 6 to postpartum/lactation day 20). Prolonged parturition duration and reduced offspring viability were observed at a maternally toxic dose (1500 mg/kg/day). No adverse maternal or offspring effects were observed at doses ≤500 mg/kg/day, resulting in systemic drug exposures (based on AUC for oseltamivir carboxylate) 44 times human exposures at the MRHD of TAMIFLU.

Pediatric use

8.4 Pediatric Use Treatment of Influenza The safety and efficacy of TAMIFLU for the treatment of influenza in pediatric patients 2 weeks old to 17 years of age has been established [see Dosage and Administration (2.2) , Clinical Pharmacology (12.3) , and Clinical Studies (14.1) ] and is based on: 13 to 17 years of age: Safety and efficacy in adolescent patients 13 to 17 years of age was supported by adequate and well-controlled trials in adults and adolescents and younger pediatric patients and safety data in adolescents treated with TAMIFLU in a study of treatment and prophylaxis. 1 year to 12 years of age: Safety and efficacy in pediatric patients 1 year to 12 years of age was supported by results of one double-blind, placebo-controlled trial in 452 pediatric patients with influenza in whom TAMIFLU 2 mg per kg twice daily or placebo was administered within 48 hours of symptom onset [see Clinical Studies (14.1) ]. Additional safety information was provided in a double-blind, placebo-controlled trial in pediatric patients 6 to 12 years of age with known asthma. Efficacy could not be established in pediatric patients with asthma. 2 weeks to less than 1 year of age: Safety and efficacy in pediatric patients 2 weeks to less than 1 year of age is supported by adequate and well-controlled trials in adults and older pediatric patients and two open-label trials of TAMIFLU (2 to 3.5 mg per kg twice daily for 5 days) in 136 pediatric subjects 2 weeks to less than 1 year of age. In these two trials, the oseltamivir plasma concentrations in these subjects were similar to or higher than the oseltamivir plasma concentrations observed in older pediatric subjects and adults [see Clinical Pharmacology (12.3) and Clinical Studies (14.1) ] . The safety and efficacy of TAMIFLU for treatment of influenza in pediatric patients less than 2 weeks of age have not been established. Prophylaxis of Influenza The safety and efficacy of TAMIFLU for the prophylaxis of influenza in pediatric patients 1 year to 17 years old has been established [see Dosage and Administration (2.3) , Clinical Pharmacology (12.3) , and Clinical Studies (14.2) ] and is based on: 13 to 17 years of age: Prophylaxis in adolescent patients 13 to 17 years of age is supported by one randomized, placebo-controlled post-exposure household prophylaxis trial of TAMIFLU 75 mg taken orally once daily for 7 days in household contacts including 207 adolescents [see Clinical Studies (14.2) ]. 1 year to 12 years of age: TAMIFLU for prophylaxis in pediatric patients 1 year to 12 years of age is supported by one randomized, open-label, post-exposure household prophylaxis trial including pediatric subjects 1 year to 12 years of age who received 30 to 60 mg of TAMIFLU for oral suspension (supplied as powder) taken orally once daily for 10 days [see Clinical Studies (14.2) ]. Additional safety information was provided in a 6-week seasonal prophylaxis (community outbreak) safety study in 49 patients 1 year to 12 years of age. The safety and efficacy of TAMIFLU for prophylaxis of influenza have not been established for pediatric patients less than 1 year of age.

Geriatric use

8.5 Geriatric Use Treatment of Influenza Of the 4,765 adults in clinical trials of TAMIFLU for the treatment of influenza, 948 (20%) were 65 years and older, while 329 (7%) were 75 years and older. In three double-blind, placebo-controlled trials in the treatment of influenza in patients at least 65 years old, that enrolled 741 subjects (374 received placebo and 362 received TAMIFLU), no overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger subjects [see Clinical Studies (14.1) ] . Prophylaxis of Influenza Of the 4,603 adults in clinical trials of TAMIFLU for the prophylaxis of influenza, 1,046 (23%) were 65 years and older, while 719 (16%) were 75 years and older. In a randomized, placebo-controlled trial in elderly residents of nursing homes who took TAMIFLU for up to 42 days for the prophylaxis of influenza (TAMIFLU n=276, placebo n=272), no overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger subjects [see Clinical Studies (14.2) ] .

Overdosage

Reports of overdoses with TAMIFLU have been received from clinical trials and during postmarketing experience. In the majority of cases reporting overdose, no adverse reactions were reported. Adverse reactions reported following overdose were similar in nature to those observed with therapeutic doses of TAMIFLU [see Adverse Reactions (6) ] .

Description

(oseltamivir phosphate), an influenza neuraminidase inhibitor (NAI), is available as: Capsules containing 30 mg, 45 mg, or 75 mg of oseltamivir for oral use, in the form of oseltamivir phosphate, and A powder for oral suspension, which when constituted with water as directed contains 6 mg per mL oseltamivir base. In addition to the active ingredient, each capsule contains croscarmellose sodium, povidone K30, pregelatinized starch, sodium stearyl fumarate and talc. The 30 mg capsule shell contains gelatin, red iron oxide, titanium dioxide, and yellow iron oxide. The 45 mg capsule shell contains black iron oxide, gelatin, and titanium dioxide. The 75 mg capsule shell contains black iron oxide, gelatin, red iron oxide, titanium dioxide, and yellow iron oxide. Each capsule is printed with blue ink, which includes FD&C Blue No. 2 as the colorant. In addition to the active ingredient, the powder for oral suspension contains monosodium citrate, saccharin sodium, sodium benzoate, sorbitol, titanium dioxide, tutti-frutti flavoring, and xanthan gum. Oseltamivir phosphate is a white crystalline solid with the chemical name (3R,4R,5S)-4-acetylamino-5-amino-3(1-ethylpropoxy)-1-cyclohexene-1-carboxylic acid, ethyl ester, phosphate (1:1). The chemical formula is C 16 H 28 N 2 O 4 (free base). The molecular weight is 312.4 for oseltamivir free base and 410.4 for oseltamivir phosphate salt. The structural formula is as follows: Chemical Structure

Mechanism of action

12.1 Mechanism of Action Oseltamivir is an antiviral drug with activity against influenza virus [see Microbiology (12.4) ].

How supplied

Capsules 30-mg capsules (30 mg free base equivalent of the phosphate salt): light yellow hard gelatin capsules. "ROCHE" is printed in blue ink on the light yellow body and "30 mg" is printed in blue ink on the light yellow cap. Available in blister packages of 10 (NDC 0004-0802-85). 45-mg capsules (45 mg free base equivalent of the phosphate salt): grey hard gelatin capsules. "ROCHE" is printed in blue ink on the grey body and "45 mg" is printed in blue ink on the grey cap. Available in blister packages of 10 (NDC 0004-0801-85). 75-mg capsules (75 mg free base equivalent of the phosphate salt): grey/light yellow hard gelatin capsules. "ROCHE" is printed in blue ink on the grey body and "75 mg" is printed in blue ink on the light yellow cap. Available in blister packages of 10 (NDC 0004-0800-85). Storage Store the capsules at 25ºC (77ºF); excursions permitted to 15º to 30ºC (59º to 86ºF) [See USP Controlled Room Temperature]. TAMIFLU for Oral Suspension (Supplied as Powder) Supplied as a white powder blend in a glass bottle. After constitution, the powder blend produces a white tutti-frutti–flavored oral suspension. After constitution with 55 mL of water, each bottle delivers a usable volume of 60 mL of oral suspension equivalent to 360 mg oseltamivir base (6 mg/mL) [see Dosage and Administration (2.5) ] (NDC 0004-0822-05). Storage Store dry powder at 25ºC (77ºF); excursions permitted to 15º to 30ºC (59º to 86ºF) [See USP Controlled Room Temperature]. Store constituted oral suspension under refrigeration for up to 17 days at 2º to 8ºC (36º to 46ºF). Do not freeze. Alternatively, store constituted oral suspension for up to 10 days at 25ºC (77ºF); excursions permitted to 15º to 30ºC (59º to 86ºF) [See USP Controlled Room Temperature].

Storage

Storage Store the capsules at 25ºC (77ºF); excursions permitted to 15º to 30ºC (59º to 86ºF) [See USP Controlled Room Temperature]. Storage Store dry powder at 25ºC (77ºF); excursions permitted to 15º to 30ºC (59º to 86ºF) [See USP Controlled Room Temperature]. Store constituted oral suspension under refrigeration for up to 17 days at 2º to 8ºC (36º to 46ºF). Do not freeze. Alternatively, store constituted oral suspension for up to 10 days at 25ºC (77ºF); excursions permitted to 15º to 30ºC (59º to 86ºF) [See USP Controlled Room Temperature].

Patient information

Advise the patient to read the FDA-approved patient labeling (Patient Information and Instructions for Use). Serious Skin/Hypersensitivity Reactions Advise patients and/or caregivers of the risk of severe allergic reactions (including anaphylaxis) or serious skin reactions. Instruct patients and/or caregiver to stop TAMIFLU and seek immediate medical attention if an allergic-like reaction occurs or is suspected [ see Warnings and Precautions (5.1) ] . Neuropsychiatric Events Advise patients and/or caregivers of the risk of neuropsychiatric events in TAMIFLU-treated patients with influenza and instruct patients to contact their physician if they experience signs of abnormal behavior while receiving TAMIFLU [see Warnings and Precautions (5.2) ] . Important Dosing Information Instruct patients to begin treatment with TAMIFLU as soon as possible from the first appearance of flu symptoms, within 48 hours of onset of symptoms. Similarly, instruct patients to start taking TAMIFLU for prevention as soon as possible after exposure [ see Dosage and Administration (2) ] . Instruct patients to take any missed doses as soon as they remember, except if it is near the next scheduled dose (within 2 hours), and then continue to take TAMIFLU at the usual times. Influenza Vaccines Instruct patients that TAMIFLU is not a substitute for receiving an annual flu vaccination. Patients should continue receiving an annual flu vaccination according to guidelines on immunization practices. Because of the potential for TAMIFLU to inhibit replication of live attenuated influenza vaccine (LAIV) and possibly reduce efficacy of LAIV, avoid administration of LAIV within 2 weeks or 48 hours after TAMIFLU administration, unless medically necessary [see Drug Interactions (7.1) ]. Fructose Intolerance Inform patients with hereditary fructose intolerance that one dose of 75 mg TAMIFLU oral suspension (supplied as powder) delivers 2 grams of sorbitol. Inform patients with hereditary fructose intolerance that this is above the daily maximum limit of sorbitol and may cause dyspepsia and diarrhea [see Warnings and Precautions (5.4) ] .

Active ingredients

Oseltamivir Phosphate in 3 products

Tamiflu NDC products (3)

NDC	Strength & form	Labeler	Type
0004-0800	Oseltamivir Phosphate 75 mg/1 Capsule	Genentech, Inc.	NDA
0004-0802	Oseltamivir Phosphate 30 mg/1 Capsule	Genentech, Inc.	NDA
0004-0822	Oseltamivir Phosphate 6 mg/mL Powder, For Suspension	Genentech, Inc.	NDA

Frequently asked questions

What is Tamiflu used for?

1 INDICATIONS AND USAGE TAMIFLU is an influenza neuraminidase inhibitor (NAI) indicated for: Treatment of acute, uncomplicated influenza A and B in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. ( 1.1 ) Prophylaxis of influenza A and B in patients 1 year and older. ( 1.2 ) Limitations of Use : Not a substitute for annual influenza vaccination. ( 1.3 )…

What are the side effects of Tamiflu?

The following serious adverse reactions are discussed below and elsewhere in the labeling: Serious skin and hypersensitivity reactions [see Warnings and Precautions (5.1) ] Neuropsychiatric events [see Warnings and Precautions (5.2) ] Most common adverse reactions (>1% and more common than with placebo): Treatment studies – Nausea, vomiting, headache. ( 6.1 ) Prophylaxis studies – Nausea,… See the full label for the complete list.

Who makes Tamiflu?

Tamiflu is listed by 1 labeler in the FDA NDC directory, including Genentech, Inc..