Home Drug Guide Oseltamivir Phosphate

Drug Guide

Generic Name

Oseltamivir Phosphate

Brand Names Tamiflu

Classification

Therapeutic: Antiviral for Influenza

Pharmacological: Neuraminidase Inhibitor

FDA Approved Indications

  • Treatment of acute uncomplicated influenza in patients 2 weeks and older
  • Prophylaxis of influenza in patients 1 year and older

Mechanism of Action

Oseltamivir inhibits the influenza virus neuraminidase enzyme, preventing release of new viral particles from infected cells, thereby limiting viral spread.

Dosage and Administration

Adult: 75 mg twice daily for 5 days for treatment; 75 mg once daily for 10 days for prophylaxis

Pediatric: Treatment: 30-75 mg twice daily based on weight; Prophylaxis: 30-75 mg once daily based on weight, for 10 days; doses adjusted for children with renal impairment

Geriatric: Same as adults; dose adjustment recommended in renal impairment

Renal Impairment: Dose adjustment required; see prescribing information

Hepatic Impairment: No specific adjustment recommended; use with caution.

Pharmacokinetics

Absorption: Rapidly absorbed after oral administration

Distribution: Widely distributed in body tissues and fluids

Metabolism: Metabolized to an active carboxylate form by hepatic esterases

Excretion: Primarily renal excretion of unchanged drug and active metabolite

Half Life: Approximately 1-3 hours in healthy individuals

Contraindications

  • Hypersensitivity to oseltamivir or any component of the formulation

Precautions

  • Use with caution in patients with renal impairment; monitor for neuropsychiatric effects, especially in pediatric populations

Adverse Reactions - Common

  • Nausea (More than 10% of users)
  • Vomiting (More than 10% of users)
  • Headache (Less than 10% of users)

Adverse Reactions - Serious

  • Neuropsychiatric events (including confusion, hallucinations, abnormal behavior) (Rare)
  • Anaphylaxis and serious skin reactions (Very rare)

Drug-Drug Interactions

  • Live attenuated influenza vaccine (avoid concomitant use)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for symptoms of influenza and neuropsychiatric status

Diagnoses:

  • Risk for infection
  • Risk for neuropsychiatric effects

Implementation: Administer within 48 hours of symptom onset for treatment; as prescribed for prophylaxis

Evaluation: Assess improvement in symptoms or prevention of influenza after therapy

Patient/Family Teaching

  • Take medication with food to reduce nausea
  • Complete the full course of therapy
  • Report any neuropsychiatric symptoms or allergic reactions immediately
  • Practice good hygiene to prevent influenza

Special Considerations

Black Box Warnings:

  • Neuropsychiatric effects, including severe mental status and behavior changes, have been reported, mostly in pediatric patients

Genetic Factors: No specific genetic considerations identified

Lab Test Interference: None significant

Overdose Management

Signs/Symptoms: Nausea, vomiting, hallucinations, agitation, delirium

Treatment: Supportive care, no specific antidote; dialysis may help remove unmetabolized drug in severe cases

Storage and Handling

Storage: Store at 2°C to 25°C (36°F to 77°F).

Stability: Stable under recommended storage conditions for up to 17 months.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.