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ZANAMIVIR

Medical Diagnosis and Drugs, Medications
ZANAMIVIR
(zan'a-mi-vir)
Relenza
Classifications: antiviral;
Therapeutic: antiinfluenza
Pregnancy Category: C

Availability

5 mg/Rotadisk blister

Action

Inhibitor of influenza A and B viral enzyme; does not permit the release of newly formed viruses from the surface of the infected cells.

Therapeutic Effect

Prevents viral spread across the mucus lining of the respiratory tract, and inhibits the replication of influenza A and B virus. Relieves flu-like symptoms.

Uses

Uncomplicated acute influenza in patients symptomatic <2 d.

Contraindications

Hypersensitivity to zanamivir or milk protein; severe renal impairment, renal failure; pregnancy (category C); COPD; severe asthma.

Cautious Use

Concurrent use of inhaled medication with inhaled zanamivir; renal impairment; cardiac disease; older adults; severe metablic disease; lactation. Safety and efficacy in children <7 y are unknown. Safe use in prophylactic treatment for children <5 y unknown.

Route & Dosage

Acute Influenza
Adult/Child (>7 y): Inhaled 2 inhalations (one 5 mg blister/inhalation) b.i.d. (approximately 12 h apart) x 5 d

Influenza Prophylaxis
Adult/Child (>5 y): Inhaled 2 inhalations daily for 10 d (household prophylaxis) or 2 inhalations daily for 28 d (community outbreak)

Administration

Inhalation
  • Initiate within 48 h of onset of flu-like symptoms.
  • Give any scheduled inhaled bronchodilator before zanamivir.
  • Store at 25° C (77° F).

Adverse Effects (≥1%)

Body as a Whole: Headache. CNS: Dizziness. GI: Nausea, diarrhea, vomiting. Respiratory: Nasal symptoms, bronchitis, cough, sinusitis; ear, nose, throat infection.

Interactions

Drug: No clinically significant interactions established.

Pharmacokinetics

Absorption: 4–17% of inhaled dose is systemically absorbed. Peak: 1–2 h. Distribution: <10% protein bound. Metabolism: Not metabolized. Elimination: In urine. Half-Life: 2.5–5.1 h.

Nursing Implications

Patient & Family Education

  • Start within 48 h of onset of flu-like symptoms for most effective response.
  • Use any scheduled inhaled bronchodilator first; then use zanamivir.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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