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oseltamivir (oh-sel-tam-i-vir)



Therapeutic: antivirals

Pharmacologic: neuramidase inhibitors


Treatment of uncomplicated acute illness due to influenza infection in adults and children ≥1 yr who have had symptoms for ≤2 days. Prevention of influenza in patients ≥1 yr.


Inhibits the enzyme neuramidase, which may alter virus particle aggregation and release. Therapeutic Effects: Reduced duration or prevention of flu-related symptoms.

Adverse Reactions/Side Effects

CNS: SEIZURES, abnormal behavior, agitation, confusion, delirium, hallucinations, insomnia, nightmares, vertigo. Resp: bronchitis. GI: nausea, vomiting.


Examination and Evaluation

  • Be alert for new seizures or increased seizure activity, especially at the onset of drug treatment. Document the number, duration, and severity of seizures, and report these findings immediately to the physician.

  • Be alert for agitation, confusion, delirium, hallucinations, or other abnormal behaviors. Notify physician or nursing staff promptly if these symptoms develop.

  • Be alert for vertigo that might affect gait, balance, or other functional activities. Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

  • Assess any breathing problems, and report signs of prolonged or severe bronchitis (cough, mucous production, shortness of breath, wheezing, chest discomfort, fatigue, fever, chills).


  • Always wash hands thoroughly and disinfect equipment (whirlpools, electrotherapeutic devices, treatment tables, and so forth) to help prevent the spread of infection. Use universal precautions as indicated for specific patients.

Patient/Client-Related Instruction

  • Instruct patient and family/caregivers to report other troublesome side effects, including severe or prolonged insomnia, nightmares, or GI problems (nausea, vomiting).


Absorption: Rapidly absorbed from the GI tract and converted by the liver to the active form, oseltamivir carboxylate. 75% reaches systemic circulation as the active drug.

Distribution: Unknown.

Metabolism and Excretion: Rapidly metabolized by the liver to oseltamivir carboxylate, the active drug. Oseltamivir is >99% excreted unchanged in urine.

Half-life: Oseltamivir carboxylate—6–10 hr.

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TIME/ACTION PROFILE (blood levels)

PO unknown unknown 12 hr


Contraindicated in: Hypersensitivity; Pedi: Children <1 yr.

Use Cautiously in: Pedi: Children ≥1 yr (may be at ↑ risk for neuropsychiatric events); OB/Lactation: Safety not established; use only if potential benefits outweigh possible risks.


Drug-Drug: None significant.


Treatment of Influenza

PO (Adults and Children >40 kg): 75 mg bid ...

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