oseltamivir phosphate

oseltamivir phosphate

Tamiflu

Pharmacologic class: Viral neuroaminidase 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: 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 more than 7 days, starting within 2 days of exposure

➣ 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.

Administration

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

Route	Onset	Peak	Duration
P.O.	Variable	2.5	6 hr

Adverse reactions

CNS: headache, dizziness, fatigue, insomnia

GI: nausea, vomiting, diarrhea

Respiratory: cough, bronchitis

Interactions

None significant

Patient monitoring

• 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.
• 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.