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Details

Stereochemistry ABSOLUTE
Molecular Formula C16H28N2O4.H3O4P
Molecular Weight 410.3997
Optical Activity UNSPECIFIED
Defined Stereocenters 3 / 3
E/Z Centers 0
Charge 0

SHOW SMILES / InChI
Structure of OSELTAMIVIR PHOSPHATE

SMILES

OP(O)(O)=O.CCOC(=O)C1=C[C@@H](OC(CC)CC)[C@H](NC(C)=O)[C@@H](N)C1

InChI

InChIKey=PGZUMBJQJWIWGJ-ONAKXNSWSA-N
InChI=1S/C16H28N2O4.H3O4P/c1-5-12(6-2)22-14-9-11(16(20)21-7-3)8-13(17)15(14)18-10(4)19;1-5(2,3)4/h9,12-15H,5-8,17H2,1-4H3,(H,18,19);(H3,1,2,3,4)/t13-,14+,15+;/m0./s1

HIDE SMILES / InChI

Molecular Formula C16H28N2O4
Molecular Weight 312.4045
Charge 0
Count
Stereochemistry ABSOLUTE
Additional Stereochemistry No
Defined Stereocenters 3 / 3
E/Z Centers 0
Optical Activity UNSPECIFIED

Molecular Formula H3O4P
Molecular Weight 97.9952
Charge 0
Count
Stereochemistry ACHIRAL
Additional Stereochemistry No
Defined Stereocenters 0 / 0
E/Z Centers 0
Optical Activity NONE

Description
Curator's Comment: Description was created based on several sources, including http://www.fda.gov/downloads/drugs/drugsafety/informationbydrugclass/ucm147992.pdf

Oseltamivir phosphate is an ethyl ester prodrug requiring ester hydrolysis for conversion to the active form, oseltamivir carboxylate. Oseltamivir carboxylate is an inhibitor of influenza virus neuraminidase affecting release of viral particles. Oseltamivir is a well tolerated orally active neuraminidase inhibitor which significantly reduces the duration of symptomatic illness and hastens the return to normal levels of activity when initiated promptly in patients with naturally acquired influenza.

CNS Activity

Curator's Comment: CNS penetration of oseltamivir and oseltamivir carboxylate is low in Japanese and Caucasian adults. Emerging data support the idea that oseltamivir and oseltamivir carboxylate have limited potential to induce or exacerbate CNS adverse events in individuals with influenza.

Originator

Curator's Comment: Oseltamivir was invented and patented by Californian company Gilead Sciences in 1996. Swiss pharmaceutical company Hoffmann-La Roche (Roche) then purchased the rights to develop and market the drug worldwide under the trade name Tamiflu.

Approval Year

Targets

Targets

Primary TargetPharmacologyConditionPotency
1.34 nM [IC50]
13.0 nM [IC50]
Conditions

Conditions

ConditionModalityTargetsHighest PhaseProduct
Primary
TAMIFLU

Approved Use

TAMIFLU is indicated for the treatment of uncomplicated acute illness due to influenza infection in patients 1 year and older who have been symptomatic for no more than 2 days.

Launch Date

1999
Cmax

Cmax

ValueDoseCo-administeredAnalytePopulation
441 μg/L
150 mg single, oral
dose: 150 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: FED
551 μg/L
150 mg single, oral
dose: 150 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: FASTED
230 μg/L
50 mg 2 times / day steady-state, oral
dose: 50 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
439 μg/L
100 mg 2 times / day steady-state, oral
dose: 100 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
1132 μg/L
200 mg 2 times / day steady-state, oral
dose: 200 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
2458 μg/L
500 mg 2 times / day steady-state, oral
dose: 500 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
348 ng/mL
75 mg 2 times / day multiple, oral
dose: 75 mg
route of administration: Oral
experiment type: MULTIPLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: UNKNOWN
age: UNKNOWN
sex: UNKNOWN
food status: UNKNOWN
AUC

AUC

ValueDoseCo-administeredAnalytePopulation
6069 μg × h/L
150 mg single, oral
dose: 150 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: FED
6218 μg × h/L
150 mg single, oral
dose: 150 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: FASTED
2107 μg × h/L
50 mg 2 times / day steady-state, oral
dose: 50 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
3845 μg × h/L
100 mg 2 times / day steady-state, oral
dose: 100 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
8612 μg × h/L
200 mg 2 times / day steady-state, oral
dose: 200 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
20317 μg × h/L
500 mg 2 times / day steady-state, oral
dose: 500 mg
route of administration: Oral
experiment type: STEADY-STATE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: UNKNOWN
2719 ng × h/mL
75 mg 2 times / day multiple, oral
dose: 75 mg
route of administration: Oral
experiment type: MULTIPLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: UNKNOWN
age: UNKNOWN
sex: UNKNOWN
food status: UNKNOWN
T1/2

T1/2

ValueDoseCo-administeredAnalytePopulation
8.2 h
150 mg single, oral
dose: 150 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: FED
6.87 h
150 mg single, oral
dose: 150 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: UNKNOWN
food status: FASTED
8 h
75 mg 2 times / day multiple, oral
dose: 75 mg
route of administration: Oral
experiment type: MULTIPLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: UNKNOWN
age: UNKNOWN
sex: UNKNOWN
food status: UNKNOWN
Funbound

Funbound

ValueDoseCo-administeredAnalytePopulation
97%
75 mg 2 times / day multiple, oral
dose: 75 mg
route of administration: Oral
experiment type: MULTIPLE
co-administered:
OSELTAMIVIR ACID plasma
Homo sapiens
population: UNKNOWN
age: UNKNOWN
sex: UNKNOWN
food status: UNKNOWN
Doses

Doses

DosePopulationAdverse events​
1000 mg single, oral
Highest studied dose
Dose: 1000 mg
Route: oral
Route: single
Dose: 1000 mg
Sources:
healthy, 18-55
Health Status: healthy
Age Group: 18-55
Sex: M
Sources:
500 mg 2 times / day multiple, oral
Highest studied dose
Dose: 500 mg, 2 times / day
Route: oral
Route: multiple
Dose: 500 mg, 2 times / day
Sources:
healthy, 18-55
Health Status: healthy
Age Group: 18-55
Sex: M
Sources:
450 mg 2 times / day multiple, oral
Higher than recommended
Dose: 450 mg, 2 times / day
Route: oral
Route: multiple
Dose: 450 mg, 2 times / day
Sources:
healthy, 33.9±11.52
Health Status: healthy
Age Group: 33.9±11.52
Sex: M+F
Sources:
75 mg 2 times / day multiple, oral
Recommended
Dose: 75 mg, 2 times / day
Route: oral
Route: multiple
Dose: 75 mg, 2 times / day
Sources:
unhealthy
Disc. AE: Nausea, Vomiting...
AEs leading to
discontinuation/dose reduction:
Nausea (rare)
Vomiting (rare)
Sources:
AEs

AEs

AESignificanceDosePopulation
Nausea rare
Disc. AE
75 mg 2 times / day multiple, oral
Recommended
Dose: 75 mg, 2 times / day
Route: oral
Route: multiple
Dose: 75 mg, 2 times / day
Sources:
unhealthy
Vomiting rare
Disc. AE
75 mg 2 times / day multiple, oral
Recommended
Dose: 75 mg, 2 times / day
Route: oral
Route: multiple
Dose: 75 mg, 2 times / day
Sources:
unhealthy
PubMed

PubMed

TitleDatePubMed
Influence of treatment schedule and viral challenge dose on the in vivo influenza virus-inhibitory effects of the orally administered neuraminidase inhibitor GS 4104.
1999 Jul
Identifying research priorities on infections in older adults: proceedings of an interdisciplinary workshop.
2001
Pharmacokinetics and dosage recommendations for an oseltamivir oral suspension for the treatment of influenza in children.
2001
Are we ready for the next flu pandemic?
2001 Dec
Cost-effectiveness of vaccination versus treatment of influenza in healthy adolescents and adults.
2001 Dec 1
Treatment of influenza with neuraminidase inhibitors: virological implications.
2001 Dec 29
[What is current opinion of antiviral therapy for the flu in 2001?].
2001 Jan
Symptom pathogenesis during acute influenza: interleukin-6 and other cytokine responses.
2001 Jul
Advances in pharmacology. New treatments for influenza: neuraminidase inhibitors.
2001 Jun
Position statement: global neuraminidase inhibitor susceptibility network.
2001 Mar
Zanamivir and oseltamivir: two new options for the treatment and prevention of influenza.
2001 Mar
Cyclopentane neuraminidase inhibitors with potent in vitro anti-influenza virus activities.
2001 Mar
New, azide-free transformation of epoxides into 1,2-diamino compounds: synthesis of the anti-influenza neuraminidase inhibitor oseltamivir phosphate (Tamiflu).
2001 Mar 23
Utilization of alpha-1-acid glycoprotein levels in the serum as a parameter for in vivo assay of influenza virus inhibitors.
2001 Nov
Vaccines for pneumonia and new antiviral therapies.
2001 Nov
Oseltamivir: a clinical and pharmacological perspective.
2001 Oct
Antivirals for influenza: what is their role in the older patient?
2002
Highlights in the development of new antiviral agents.
2002 Apr
Antiviral therapy of influenza.
2002 Apr
Use of oseltamivir during influenza outbreaks in Ontario nursing homes, 1999-2000.
2002 Apr
Challenges and options in the management of viral infections after stem cell transplantation.
2002 Apr
Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP).
2002 Apr 12
The H274Y mutation in the influenza A/H1N1 neuraminidase active site following oseltamivir phosphate treatment leave virus severely compromised both in vitro and in vivo.
2002 Aug
Oseltamivir for influenza.
2002 Dec
Neuraminidase inhibitors for the treatment and prevention of influenza.
2002 Feb
Antiviral therapy for influenza virus infections.
2002 Jan
Is oral oseltamivir safe and effective for the prevention of influenza and its complications in frail elderly long-term care residents who have received influenza vaccine?
2002 Jan
The anti-influenza drug oseltamivir exhibits low potential to induce pharmacokinetic drug interactions via renal secretion-correlation of in vivo and in vitro studies.
2002 Jan
Oseltamivir was safe and effective for prophylaxis of influenza in the frail elderly.
2002 Jan-Feb
Susceptibility of recent Canadian influenza A and B virus isolates to different neuraminidase inhibitors.
2002 Jun
Influenza virus carrying neuraminidase with reduced sensitivity to oseltamivir carboxylate has altered properties in vitro and is compromised for infectivity and replicative ability in vivo.
2002 May
Experience with oseltamivir in the control of nursing home influenza A outbreak.
2002 May
Influenza surveillance with rapid diagnostic tests.
2002 May 15
[New diagnostic possibilities and medications. Fit for influenza?].
2002 Nov 28
Characterization of 2 influenza A(H3N2) clinical isolates with reduced susceptibility to neuraminidase inhibitors due to mutations in the hemagglutinin gene.
2002 Oct 15
Cost-effectiveness of newer treatment strategies for influenza.
2002 Sep
Influenza vaccination and antiviral therapy: is there a role for concurrent administration in the institutionalised elderly?
2003
Neuraminidase inhibitors in pediatric patients: potential place in influenza therapy.
2003
Influenza diagnosis and treatment in children: a review of studies on clinically useful tests and antiviral treatment for influenza.
2003 Feb
Logistic issues and potential prescribing costs associated with use of neuraminidase inhibitors for the treatment of influenza in primary care.
2003 Feb
Antiviral drugs in the immunocompetent host: part II. Treatment of influenza and respiratory syncytial virus infections.
2003 Feb 15
Patents

Sample Use Guides

The recommended oral dose of TAMIFLU (oseltamivir phosphate) for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily for 5 days. Treatment should begin within 2 days of onset of symptoms of influenza.
Route of Administration: Oral
Oseltamivir also showed moderate antiviral activity in Madine-Darby canine kidney cells of about 83% against influenza A/HK (H3N2) virus at the concentration of 100 μg/ml.
Substance Class Chemical
Created
by admin
on Mon Mar 31 18:27:32 GMT 2025
Edited
by admin
on Mon Mar 31 18:27:32 GMT 2025
Record UNII
4A3O49NGEZ
Record Status Validated (UNII)
Record Version
  • Download
Name Type Language
AGUCORT
Preferred Name English
OSELTAMIVIR PHOSPHATE
EP   JAN   MART.   MI   ORANGE BOOK   USAN   USP   USP-RS   VANDF   WHO-DD   WHO-IP  
USAN  
Official Name English
OSELTAMIVIR (AS PHOSPHATE)
Common Name English
TAMIFLU
Brand Name English
OSELTAMIVIR PHOSPHATE [USP-RS]
Common Name English
OSELTAMIVIR PHOSPHATE [JAN]
Common Name English
OSELTAMIVIR PHOSPHATE [WHO-IP]
Common Name English
OSELTAMIVIR PHOSPHATE [MART.]
Common Name English
OSELTAMIVIR PHOSPHATE [VANDF]
Common Name English
OSELTAMIVIR PHOSPHATE [EP MONOGRAPH]
Common Name English
ETHYL-(3R,4R,5S)-4-ACETAMIDO-5-AMINO-3-(1-ETHYLPROPOXY)-1-CYCLOHEXENE-1-CARBOXYLATE PHOSPHATE
Systematic Name English
RO 64-0796/002
Code English
RO-64-0796/002
Code English
OSELTAMIVIR PHOSPHATE [MI]
Common Name English
OSELTAMIVIR PHOSPHATE [USAN]
Common Name English
OSELTAMIVIRI PHOSPHAS [WHO-IP LATIN]
Common Name English
OSELTAMIVIR PHOSPHATE [USP MONOGRAPH]
Common Name English
OSELTAMIVIR PHOSPHATE [USP IMPURITY]
Common Name English
(3R-(3.ALPHA.,4.BETA.,5.ALPHA.))-ETHYL 4-(ACETYLAMINO)-5-AMINO-3-(1-ETHYLPROPOXY)-1-CYCLOHEXENE-1-CARBOXYLATE PHOSPHATE (1:1)
Common Name English
OSELTAMIVIR PHOSPHATE [ORANGE BOOK]
Common Name English
RO-64-0796-002
Code English
Oseltamivir phosphate [WHO-DD]
Common Name English
Classification Tree Code System Code
NCI_THESAURUS C281
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
Code System Code Type Description
EPA CompTox
DTXSID0044230
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
EVMPD
SUB12544MIG
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
MERCK INDEX
m8256
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY Merck Index
USAN
KK-62
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
NCI_THESAURUS
C29305
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
RS_ITEM_NUM
1479304
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
ChEMBL
CHEMBL1229
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
FDA UNII
4A3O49NGEZ
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
CHEBI
7799
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
PUBCHEM
78000
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
SMS_ID
100000091466
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
DAILYMED
4A3O49NGEZ
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
CAS
204255-11-8
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
WHO INTERNATIONAL PHARMACOPEIA
OSELTAMIVIR PHOSPHATE
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY Description: A white to off-white powder. Solubility: Freely soluble in water and in methanol. Category: Antiviral. Storage: Oseltamivir phosphate should be kept in a well-closed container, protected from light. Additional information: Oseltamivir phosphate may show polymorphism. Definition: Oseltamivir phosphate contains not less than 97.5% and not more than 102.0% of oseltamivir phosphate (C16H28N2O4, H3PO4) using Assay method A, and not less than 98.5% and not more than 101.0% of oseltamivir phosphate (C16H28N2O4, H3PO4) using Assay method B, both calculated with reference to the anhydrous substance.
RXCUI
259275
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY RxNorm
CHEBI
7798
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
DRUG BANK
DB00198
Created by admin on Mon Mar 31 18:27:32 GMT 2025 , Edited by admin on Mon Mar 31 18:27:32 GMT 2025
PRIMARY
Related Record Type Details
BASIS OF STRENGTH->SUBSTANCE
ASSAY (HPLC)
USP
BASIS OF STRENGTH->SUBSTANCE
ASSAY (HPLC)
EP
PARENT -> SALT/SOLVATE
Related Record Type Details
IMPURITY -> PARENT
Use the chromatogram obtained with solution (4) to identify the peaks due to impurities A, B, C and D. The impurity peaks are eluted at the following relative retention with reference to oseltamivir phosphate (retention time about 19 minutes): impurity A about 0.16. The test is not valid unless the resolution between the peaks due to impurities A and B and that between the peaks due to impurities C and D is at least 1.3.
IMPURITY -> PARENT
IMPURITY -> PARENT
UNSPECIFIED
EP
IMPURITY -> PARENT
CHROMATOGRAPHIC PURITY (HPLC/UV)
USP
IMPURITY -> PARENT
UNSPECIFIED
EP
IMPURITY -> PARENT
UNSPECIFIED
EP
IMPURITY -> PARENT
CHROMATOGRAPHIC PURITY (HPLC/UV)
EP
IMPURITY -> PARENT
Use the chromatogram obtained with solution (4) to identify the peaks due to impurities A, B, C and D. The impurity peaks are eluted at the following relative retention with reference to oseltamivir phosphate (retention time about 19 minutes): impurity C about 0.51. The test is not valid unless the resolution between the peaks due to impurities A and B and that between the peaks due to impurities C and D is at least 1.3.
IMPURITY -> PARENT
CHROMATOGRAPHIC PURITY (HPLC/UV)
EP
IMPURITY -> PARENT
Use the chromatogram obtained with solution (4) to identify the peaks due to impurities A, B, C and D. The impurity peaks are eluted at the following relative retention with reference to oseltamivir phosphate (retention time about 19 minutes): impurity B about 0.17. The test is not valid unless the resolution between the peaks due to impurities A and B and that between the peaks due to impurities C and D is at least 1.3.
IMPURITY -> PARENT
UNSPECIFIED
EP
IMPURITY -> PARENT
Use the chromatogram obtained with solution (4) to identify the peaks due to impurities A, B, C and D. The impurity peaks are eluted at the following relative retention with reference to oseltamivir phosphate (retention time about 19 minutes): impurity D about 0.55. The test is not valid unless the resolution between the peaks due to impurities A and B and that between the peaks due to impurities C and D is at least 1.3.
IMPURITY -> PARENT
UNSPECIFIED
EP
IMPURITY -> PARENT
CHROMATOGRAPHIC PURITY (HPLC/UV)
USP
IMPURITY -> PARENT
CHROMATOGRAPHIC PURITY (GC)
EP
Related Record Type Details
ACTIVE MOIETY