Zanamivir

INTRODUCTION

Indications

Treatment of uncomplicated acute illness caused by influenza virus in patients ≥7 yr who have been symptomatic ≤2 days. Prevention of influenza in patients ≥5 yr.

Action

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, delirium, hallucinations, nightmares. Resp: bronchospasm. Misc: allergic reactions.

PHYSICAL THERAPY IMPLICATIONS

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 to the physician immediately.

• Monitor signs of allergic reactions, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough, dyspnea) or skin reactions (rash, pruritus, urticaria). Notify the physician immediately if these reactions occur.

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

• Assess any breathing problems, and report signs of bronchospasm (wheezing, coughing, dyspnea, tightness in chest). Perform pulmonary function tests to quantify suspected changes in ventilation and respiration (See Appendices I, J,K).

Interventions

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

Patient/Client-Related Instruction

• Instruct patient and family/caregivers to report other troublesome side effects such as nightmares.

Pharmacokinetics

Absorption: 4–17% of inhaled dose is systemically absorbed.

Distribution: Unknown.

Protein Binding: <10%.

Metabolism and Excretion: Mainly excreted by kidneys as unchanged drug; unabsorbed drug is excreted in feces.

Half-life: 2.5–5.1 hr.

Contraindications/Precautions

Contraindicated in: Hypersensitivity to zanamivir or lactose.

Use Cautiously in: Chronic obstructive pulmonary disease or asthma (↑ risk of decreased lung function and/or bronchospasm); OB/Lactation: safety not established; Children <7 yr (for treatment) or <5 yr (for prophylaxis) (safety not established; children may be at ↑ risk for neuropsychiatric events).

Interactions

Drug-Drug: None noted.

Route/Dosage

Treatment

Inhalation (Adults and children ≥7 yr): 10 mg (given as 2 inhalations of 5 mg each) bid for 5 days.

Prophylaxis