oseltamivir phosphate
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.
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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
See 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.
See 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.