Relenza
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zanamivir
Pharmacologic class: Neuraminidase inhibitor
Therapeutic class: Antiviral
Pregnancy risk category C
Action
Inhibits influenza virus neuraminidase, an enzyme essential for viral replication
Availability
Powder for inhalation: 5 mg/blister
Indications and dosages
➣ Prevention of influenza
Adults and children ages 5 and older: Prophylaxis in the household setting, 2 inhalations (10 mg) once daily for 10 days. Prophylaxis during community outbreaks, 2 inhalations (10 mg) once daily for 28 days.
➣ Influenza virus A or B
Adults and children ages 7 and older: Two oral inhalations (5 mg/inhalation) b.i.d. for 5 days
Contraindications
• History of allergic reaction to components of drug, including lactose milk proteins
Precautions
Use cautiously in:
• chronic obstructive pulmonary disease, asthma, lactose intolerance
• concurrent use of live attenuated intranasal influenza vaccine (Don't administer until 48 hours after cessation of zanamivir and don't administer zanamivir until 2 weeks after administration of live attenuated influenza vaccine, unless medically indicated.)
• pregnant or breastfeeding patients
• children younger than age 7 (safety not established).
Administration
• Give two doses on day 1, spaced at least 2 hours apart. On subsequent days, space doses 12 hours apart, and give at approximately same time each day.

Adverse reactions
CNS: headache, dizziness
EENT: sinusitis, EENT infections
GI: nausea, vomiting, diarrhea
Respiratory: bronchitis, cough
Other: allergic reaction
Interactions
None significant
Patient monitoring
• Assess respiratory status. Watch closely for signs and symptoms of declining respiratory function.
Patient teaching
• Explain therapy to patient. Demonstrate how to use Diskhaler device.
• Tell patient to take drug exactly as prescribed for as long as directed, even if symptoms improve.
• If patient is also taking an inhaled bronchodilator, advise him to take bronchodilator before zanamivir.
• Emphasize that drug doesn't prevent spread of influenza to others.
• Instruct patient to immediately report worsening respiratory symptoms.
• As appropriate, review other significant adverse reactions.
zanamivir
(za-na-mi-veer) ,Relenza
(trade name)Classification
Therapeutic: antiviralsPharmacologic: neuraminidase inhibitors
Indications
Action
Therapeutic effects
Pharmacokinetics
Time/action profile (blood levels)
ROUTE | ONSET | PEAK | DURATION |
---|---|---|---|
Inhalation | rapid | 1–2 hr | 12 hr |
Contraindications/Precautions
Adverse Reactions/Side Effects
Central nervous system
- seizures (life-threatening)
- abnormal behavior
- agitation
- delirium
- hallucinations
- nightmares
Respiratory
- bronchospasm
Miscellaneous
- allergic reactions
Interactions
Drug-Drug interaction
None noted.Route/Dosage
Treatment
Prophylaxis
Availability
Nursing implications
Nursing assessment
- Assess patient for signs and symptoms of influenza (fever, headache, myalgia, cough, sore throat) before administration. Determine duration of symptoms. Indicated for patients who have been symptomatic for up to 2 days.
- Determine if patient is lactose intolerant; may cause allergic reaction.
Potential Nursing Diagnoses
Risk for infection (Indications)Implementation
- Consider available information on influenza drug susceptibility patterns and treatment effects before using zanamivir for prophylaxis.
- Inhalation: Administer 2 doses on the first day of treatment whenever possible; must have at least 2 hours between doses. Doses should be administered 12 hr apart on subsequent days. Zanamivir is only for oral inhalation via DISKHALER; do not attempt via nebulization or mechanical ventilation.
Patient/Family Teaching
- Instruct patient to use zanamivir exactly as directed and to finish entire course, even if feeling better.
- Instruct patient in the use of the DISKHALER. Patient should read the accompanying Patient Instructions for Use.
- Advise patients that zanamivir is not a substitute for a flu shot. Patients should receive annual flu shot according to immunization guidelines.
- Patients with a history of asthma should be advised to have a fast-acting inhaled bronchodilator available in case of bronchospasm following zanamivir administration. If using bronchodilator and zanamivir concurrently, administer bronchodilator first.
- Advise patients to report behavioral changes (hallucinations, delirium, and abnormal behavior) to health care professional immediately.
- Inform patient that zanamivir does not replace flu shot. Flu shot should be taken according to instructions of health care professional.
- Advise female patient to avoid zanamivir if pregnant or breast feeding.
Evaluation/Desired Outcomes
- Reduced duration or prevention of flu-related symptoms.