zanamivir
Relenza
Pregnancy Risk Category B
How supplied
Powder for inhalation: 5 mg/blister
Action
Likely exerts its antiviral action by inhibiting neuraminidase on the surface of the influenza virus, potentially altering virus particle aggregation and release.
Indications & dosage
Uncomplicated acute illness due to influenza virus in patients who have been symptomatic for no more than 2 days-
Adults and adolescents ages 12 and older: 2 oral inhalations (one 5-mg blister per inhalation for total dose of 10 mg) b.i.d. using the Diskhaler inhalation device for 5 days. Two doses should be taken on first day of treatment provided there is at least 2 hours between doses. Subsequent doses should be about 12 hours apart (in the morning and evening) at about the same time each day.
Adverse reactions
CNS: headache, dizziness.
EENT: nasal signs and symptoms; sinusitis; ear, nose, and throat infections.
GI: diarrhea, nausea, vomiting.
Respiratory: bronchitis, cough.
Interactions
None significant.
Effects on diagnostic tests
None reported.
Contraindications
Contraindicated in patients with known hypersensitivity to drug or its components.
Nursing considerations
- Use cautiously in patients with severe or decompensated chronic obstructive pulmonary disease, asthma, or other underlying respiratory disease.
- Keep in mind that patients with underlying respiratory disease should have a fast-acting bronchodilator available in case of wheezing while taking zanamivir. Patients scheduled to use an inhaled bronchodilator for asthma should use their bronchodilator before taking zanamivir.
- No data are available to support safety and efficacy of zanamivir in patients who begin treatment after 48 hours of symptoms.
- Safety and efficacy of drug haven't been established for influenza prophylaxis. Use of drug shouldn't affect evaluation of patient for annual influenza vaccination.
- Lymphopenia, neutropenia, and a rise in liver enzyme and CK levels have been reported during zanamivir treatment.
- Monitor patient for bronchospasm and decline in lung function. Stop drug, as ordered, in such situations.
Patient teaching
- Tell patient to carefully read the instructions regarding how to use the Diskhaler inhalation device properly to administer drug.
- Advise patient to keep the Diskhaler level when loading and inhaling zanamivir. Tell him to always check inside the mouthpiece of the Diskhaler before each use to make sure it's free of foreign objects.
- Tell patient to exhale fully before putting the mouthpiece in his mouth; then, keeping the Diskhaler level, to close his lips around the mouthpiece and breathe in steadily and deeply. Advise patient to hold his breath for a few seconds after inhaling to help drug stay in the lungs.
- Advise patient with underlying respiratory disease who is scheduled to use an inhaled bronchodilator to do so before taking zanamivir. Tell patient to have a fast-acting bronchodilator available in case of wheezing while taking zanamivir.
- Advise patient that it's important to finish the entire 5-day course of treatment even if he starts to feel better and symptoms improve before the fifth day.
*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