oseltamivir phosphate


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oseltamivir phosphate

Tamiflu

Pharmacologic class: Viral neuro-aminidase inhibitor

Therapeutic class: Antiviral

Pregnancy risk category C

Action

Inhibits influenza virus neuraminidase, altering viral particle aggregation and decreasing viral release from infected cells

Availability

Capsules: 30 mg, 45 mg, 75 mg

Powder for oral suspension: 12 mg/ml

Indications and dosages

To prevent influenza type A

Adults and children older than age 13: 75 mg P.O. daily for 10 days, starting within 2 days of exposure; 75 mg P.O. daily during community outbreak of influenza for up to 6 weeks

Children ages 1 and older weighing more than 40 kg (88 lb): 75 mg P.O. daily for 10 days, starting within 2 days of exposure; continue dosing during community outbreak of influenza for up to 6 weeks

Children ages 1 and older weighing more than 23 kg up to 40 kg (more than 51 lb up to 88 lb): 60 mg P.O. daily for 10 days, starting within 2 days of exposure; continue dosing during community outbreak of influenza for up to 6 weeks

Children ages 1 and older weighing more than 15 kg up to 23 kg (33 lb up to 51 lb): 45 mg P.O. daily for 10 days, starting within 2 days of exposure; continue dosing during community outbreak of influenza for up to 6 weeks

Children ages 1 and older weighing 15 kg (33 lb) or less: 30 mg P.O. daily for 10 days, starting within 2 days of exposure; continue dosing during community outbreak of influenza for up to 6 weeks

Treatment of influenza type A

Adults and children older than age 13: 75 mg P.O. b.i.d. for 5 days, starting within 2 days of symptom onset

Children ages 1 and older who weigh more than 40 kg (88 lb): 75 mg P.O. b.i.d. for 5 days, starting within 2 days of symptom onset

Children ages 1 and older who weigh more than 23 kg and up to 40 kg (51 to 88 lb): 60 mg P.O. b.i.d. for 5 days, starting within 2 days of symptom onset

Children ages 1 year and older who weigh more than 15 kg and up to 23 kg (33 to 51 lb): 45 mg P.O. b.i.d. for 5 days, starting within 2 days of symptom onset

Children ages 1 and older who weigh less than 15 kg (33 lb): 30 mg P.O. b.i.d. for 5 days, starting within 2 days of symptom onset

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:

• chronic cardiac or renal disease, respiratory disorders

• elderly patients

• pregnant or breastfeeding patients

• children younger than age 1 (safety and efficacy not established).

Administration

• For flu treatment, give first dose at onset of symptoms. For flu prevention, give within 2 days of exposure.

Adverse reactions

CNS: headache, dizziness, fatigue, insomnia, unusual behavior, confusion

GI: nausea, vomiting, diarrhea

Respiratory: cough, bronchitis

Skin: epidermal necrolysis, erythema multiforme, Stevens-Johnson syndrome

Other: hypersensitivity reactions (including anaphylaxis)

Interactions

None significant

Patient monitoring

Monitor patient closely for allergic reaction or severe rash; discontinue drug immediately if these occur.

• Closely monitor patient for unusual behavior or confusion.

• Monitor respiratory status. Watch for signs and symptoms of secondary infection.

Patient teaching

• Instruct patient to take as soon as flu symptoms occur and to complete entire course of therapy.

• Advise patient to take with food or milk to minimize GI irritation.

• Tell patient to prepare oral solution by adding water to powder and shaking well.

Instruct patient or caregiver to discontinue drug and seek immediate medical attention if rash or swelling of lips, face, or throat occurs

• Instruct patient or caregiver to report change in behavior.

• Caution patient not to share drug with others, even if they have similar symptoms.

• Instruct patient to consult prescriber before taking other drugs.

• As appropriate, review all other significant adverse reactions.

oseltamivir phosphate

A prodrug of oseltamivir carboxylate, an inhibitor of neuraminidase enzymes on the surface of influenza viruses. These enzymes are essential for the release of the viruses from infected cells and thus the proliferation throughout the body. The drug is used to treat and prevent influenza A and B. A brand name is Tamiflu. Resistance to this drug from mutations of the neuraminidase gene was reported in 2003.
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References in periodicals archive ?
substance oseltamivir phosphate (essential requirements for the substance: manufacturer cipla india ltd, india.
Oseltamivir phosphate is intended for use in patients 2 weeks of age and older who have had flu symptoms for no more than 48 hours, and for prevention of influenza in patients 1 year of age and older.
Oseltamivir phosphate is the prodrug converted by the liver to oseltamivir carboxylate, the active neuraminidase inhibitor (Roche Laboratories Inc., 2008).
The only drugs approved for the prevention and treatment of swine flu are oseltamivir phosphate (Tamiflu) and zanamivir (Relenza).
Binding of oseltamivir phosphate to these neuraminidases inhibits their activity.
Chugai attributed the strong first-quarter results to an increased stockpile of Tamiflu, known generically as oseltamivir phosphate, by the government to prevent an epidemic of a new type of influenza.
Roche has filed a supplemental new drug application (sNDA) with the FDA to market Tamiflu (oseltamivir phosphate) capsules in pediatric doses of 30 mg and 45 mg.
On November 13, 2006, FDA approved a labeling supplement for Roche Laboratories' Tamiflu (Oseltamivir Phosphate) to include a precaution about neuropsychiatric events.
The patent was filed on oseltamivir, not oseltamivir phosphate, which is the drug that is marketed.
Roche Pharmaceuticals stated in a "Dear Health Care Professional" letter that the Tamiflu (oseltamivir phosphate) package insert would contain preclinical data in which excessive doses (1,000 mg/kg) led to death in juvenile rats.
(oseltamivir phosphate, Hociae and Gilead Sciences)
Hoffman-La Roche, Inc., Nutley, NJ, has released data showing that Tamiflu (oseltamivir phosphate) has been used successfully to treat lower respiratory tract infection caused by the flu in immunocompromised patients.