oseltamivir phosphate
Tamiflu
Pregnancy Risk Category C
How supplied
Capsules: 75 mg
Action
Inhibits influenza virus enzyme neuraminidase, which is thought to play a role in viral particle aggregation and release from the host cell. Neuraminidase inhibition, therefore, appears to interfere with viral replication.
Indications & dosage
Uncomplicated, acute illness due to influenza infection in patients who have been symptomatic for 2 days or less-
Adults: 75 mg P.O. b.i.d. for 5 days.
Adjust-A-Dose: For patients with creatinine clearance less than 30 ml/minute, reduce dose to 75 mg P.O. once daily for 5 days.
Adverse reactions
CNS: dizziness, insomnia, headache, vertigo, fatigue.
GI: abdominal pain, diarrhea, nausea, vomiting.
Respiratory: bronchitis, cough.
Interactions
None significant.
Effects on diagnostic tests
None reported.
Contraindications
Contraindicated in patients with hypersensitivity to drug or its components.
Nursing considerations
- Use cautiously in patients with chronic cardiac or respiratory diseases, or any medical condition that may require imminent hospitalization. Also use cautiously in patients with renal failure, especially those with creatinine clearance less than 10 ml/minute.
- There is no evidence supporting drug use in treatment of viral infections other than influenza virus types A and B.
- Drug must be given within 2 days of onset of symptoms.
- Drug is used to treat flu symptoms, not to prevent influenza.
- Drug isn't a replacement for the annual influenza vaccination. Patients for whom vaccine is indicated should continue to receive the vaccine each fall.
- Safety and efficacy of repeated treatment courses have not been established.
- Drug may be given with meals to decrease GI adverse effects.
- It's unknown if drug or its active metabolite appear in breast milk. Use only if potential benefits outweigh potential risks to infant.
- Store at controlled room temperature (59° to 86° F [15° to 30° C]).
Patient teaching
- Instruct patient to begin treatment as soon as possible after appearance of flu symptoms.
- Inform patient that drug may be taken with or without meals. If nausea or vomiting occurs, he can take drug with food or milk.
- Tell patient that, if a dose is missed, it should be taken as soon as possible. He should skip missed dose, however, if next dose is due within 2 hours, and take the next dose on schedule.
- Advise patient to complete the full 5 days of treatment, even if symptoms are resolved.
- Alert:
patient that drug is not a replacement for the annual influenza vaccination. Patients for whom vaccine is indicated should continue to receive the vaccine each fall.
*Liquid contains alcohol. **May contain tartrazine. †Canada ‡Australia §U.K. OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING