oseltamivir phosphate
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oseltamivir phosphate
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.