Relenza Side Effects

Generic Name: zanamivir

Please note - some side effects for Relenza may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Relenza - for the Consumer

Relenza

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Relenza:

Cough; diarrhea; dizziness; headache; nausea; sinus inflammation; sore throat; stuffy nose; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); abnormal behavior; confusion; hallucinations; irregular heartbeat; mood or mental changes; seizures; shortness of breath; symptoms of infection (eg, fever, chills, persistent sore throat); trouble swallowing; wheezing.

Relenza Side Effects - for the Professional

Relenza

The most common adverse events reported in >1.5% of patients treated with Relenza and more commonly than in patients treated with placebo are:

• Treatment Studies – sinusitis, dizziness.
• Prophylaxis Studies – fever and/or chills, arthralgia and articular rheumatism. (6.1)

Side Effects by Body System

General

Zanamivir is generally well-tolerated. In clinical trials, the incidence of adverse events in patients treated with zanamivir was similar to that in the placebo (lactose vehicle) group. No single adverse effect was reported by more than 3% of the patients.

Respiratory

In an ongoing study of patients with acute influenza-like illness and underlying asthma or chronic obstructive pulmonary disease, more patients on zanamivir than on placebo experienced greater than 20% decline in FEV1 or peak expiratory flow rate. In a phase I study, bronchospasm was reported in 1 of 13 patients with mild or moderate asthma following the administration of zanamivir.

Respiratory side effects have included sinusitis (3%), cough (2%), bronchitis (2%), nasal signs and symptoms (2%), ear, nose and throat infections (2%), viral respiratory infections, congestion, rhinitis, dry throat, and nasal, throat, and tonsil discomfort/pain. Asthma, exacerbation of asthma, bronchospasm, respiratory arrest, dyspnea, lung tightness, and/or decline in lung function may occur in patients with underlying respiratory disease treated with zanamivir.

Gastrointestinal

Gastrointestinal adverse effects have included diarrhea (3%), nausea (3%), and vomiting (1%).

Hypersensitivity

Hypersensitivity reactions reported during postmarketing experience have included oropharyngeal edema, serious skin rashes, laryngitis, and laryngospasm. Allergic or allergic-like reactions have also been reported.

Nervous system

Nervous system side effects have included headache (2%) and dizziness (1% to 2%). Seizures have been reported during postmarketing experience.

Psychiatric

Abnormal behavior and delirium leading to injury, with fatal outcomes in some cases, with the use of zanamivir in influenza patients have been reported. Although frequency is unknown, based on zanamivir usage, these events appear to be uncommon. These events were primarily reported in pediatric patients and often had an abrupt onset and rapid resolution. Since influenza may be associated with neurologic and behavioral symptoms (including hallucinations, delirium, and abnormal behavior, with fatal outcomes in some cases), zanamivir's contribution to these events has not been established.

Psychiatric side effects have included delirium (including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares) during postmarketing experience.

Other

Other side effects have included malaise, fatigue, fever, facial edema, and abdominal pain in less than 1.5% of patients. Chills have also been reported.

Musculoskeletal

Musculoskeletal side effects have included myalgia and arthralgia in less than 1.5% of patients.

Dermatologic

Dermatologic side effects have included urticaria in less than 1.5% of patients. Rash, and serious cutaneous reactions have also been reported.

Hepatic

Hepatic side effects have included elevations in liver enzymes and CPK.

Hematologic

Hematologic side effects have included lymphopenia and neutropenia.

Cardiovascular

Cardiovascular side effects reported during postmarketing experience have included arrhythmias and syncope.

Renal

Renal side effects have included one case report acute renal failure, increased serum creatinine, hyperkalemia, and hypotension in a patient with multiple medical problems and multiple other medications.

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