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Relenza (Zanamivir) - Side Effects and Adverse Reactions

 
 



ADVERSE REACTIONS

See Warnings and Precautions for information about risk of serious adverse events such as bronchospasm (5.1) and allergic-like reactions (5.2), and for safety information in patients with underlying airways disease (5.1).

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The placebo used in clinical studies consisted of inhaled lactose powder, which is also the vehicle for the active drug; therefore, some adverse events occurring at similar frequencies in different treatment groups could be related to lactose vehicle inhalation.

Treatment of Influenza: Clinical Trials in Adults and Adolescents: Adverse events that occurred with an incidence ≥1.5% in treatment studies are listed in Table 1. This table shows adverse events occurring in patients ≥12 years of age receiving RELENZA 10 mg inhaled twice daily, RELENZA in all inhalation regimens, and placebo inhaled twice daily (where placebo consisted of the same lactose vehicle used in RELENZA).

Table 1. Summary of Adverse Events ≥1.5% Incidence During Treatment in Adults and Adolescents

RELENZA

Adverse Event

10 mg b.i.d. Inhaled

(n = 1,132)

All Dosing Regimens*

(n = 2,289)

Placebo

(Lactose Vehicle)

(n = 1,520)

Body as a whole

Headaches

2%

2%

3%

Digestive

Diarrhea

3%

3%

4%

Nausea

3%

3%

3%

Vomiting

1%

1%

2%

Respiratory

Nasal signs and symptoms

2%

3%

3%

Bronchitis

2%

2%

3%

Cough

2%

2%

3%

Sinusitis

3%

2%

2%

Ear, nose, and throat infections

2%

1%

2%

Nervous system

Dizziness

2%

1%

<1%

* Includes studies where RELENZA was administered intranasally (6.4 mg 2 to 4 times per day in addition to inhaled preparation) and/or inhaled more frequently (q.i.d.) than the currently recommended dose.

Additional adverse reactions occurring in less than 1.5% of patients receiving RELENZA included malaise, fatigue, fever, abdominal pain, myalgia, arthralgia, and urticaria.

The most frequent laboratory abnormalities in Phase III treatment studies included elevations of liver enzymes and CPK, lymphopenia, and neutropenia. These were reported in similar proportions of zanamivir and lactose vehicle placebo recipients with acute influenza-like illness.

Clinical Trials in Pediatric Patients: Adverse events that occurred with an incidence ≥1.5% in children receiving treatment doses of RELENZA in 2 Phase III studies are listed in Table 2. This table shows adverse events occurring in pediatric patients 5 to 12 years old receiving RELENZA 10 mg inhaled twice daily and placebo inhaled twice daily (where placebo consisted of the same lactose vehicle used in RELENZA).

Table 2. Summary of Adverse Events ≥1.5% Incidence During Treatment in Pediatric Patients*

* Includes a subset of patients receiving RELENZA for treatment of influenza in a prophylaxis study.

Adverse Event

RELENZA

10 mg b.i.d. Inhaled

(n = 291)

Placebo

(Lactose Vehicle)

(n = 318)

Respiratory

Ear, nose, and throat infections

5%

5%

Ear, nose, and throat hemorrhage

<1%

2%

Asthma

<1%

2%

Cough

<1%

2%

Digestive

Vomiting

2%

3%

Diarrhea

2%

2%

Nausea

<1%

2%

In 1 of the 2 studies described in Table 2, some additional information is available from children (5 to 12 years old) without acute influenza-like illness who received an investigational prophylaxis regimen of RELENZA; 132 children received RELENZA and 145 children received placebo. Among these children, nasal signs and symptoms (zanamivir 20%, placebo 9%), cough (zanamivir 16%, placebo 8%), and throat/tonsil discomfort and pain (zanamivir 11%, placebo 6%) were reported more frequently with RELENZA than placebo. In a subset with chronic pulmonary disease, lower respiratory adverse events (described as asthma, cough, or viral respiratory infections which could include influenza-like symptoms) were reported in 7 of 7 zanamivir recipients and 5 of 12 placebo recipients.

Prophylaxis of Influenza: Family/Household Prophylaxis Studies: Adverse events that occurred with an incidence of ≥1.5% in the 2 prophylaxis studies are listed in Table 3. This table shows adverse events occurring in patients ≥5 years of age receiving RELENZA 10 mg inhaled once daily for 10 days.

Table 3. Summary of Adverse Events ≥1.5% Incidence During 10-Day Prophylaxis Studies in Adults, Adolescents, and Children*

* In prophylaxis studies, symptoms associated with influenza-like illness were captured as adverse events; subjects were enrolled during a winter respiratory season during which time any symptoms that occurred were captured as adverse events.

Adverse Event

Contact Cases

RELENZA

(n = 1,068)

Placebo

(n = 1,059)

Lower respiratory

Viral respiratory infections

13%

19%

Cough

7%

9%

Neurologic

Headaches

13%

14%

Ear, nose, and throat

Nasal signs and symptoms

12%

12%

Throat and tonsil discomfort and pain

8%

9%

Nasal inflammation

1%

2%

Musculoskeletal

Muscle pain

3%

3%

Endocrine and metabolic

Feeding problems (decreased or increased appetite and anorexia)

2%

2%

Gastrointestinal

Nausea and vomiting

1%

2%

Non-site specific

Malaise and fatigue

5%

5%

Temperature regulation disturbances (fever and/or chills)

5%

4%

Community Prophylaxis Studies: Adverse events that occurred with an incidence of ≥1.5% in 2 prophylaxis studies are listed in Table 4. This table shows adverse events occurring in patients ≥5 years of age receiving RELENZA 10 mg inhaled once daily for 28 days.

Table 4. Summary of Adverse Events ≥1.5% Incidence During 28-Day Prophylaxis Studies in Adults, Adolescents, and Children*

* In prophylaxis studies, symptoms associated with influenza-like illness were captured as adverse events; subjects were enrolled during a winter respiratory season during which time any symptoms that occurred were captured as adverse events.

Adverse Event

RELENZA

(n = 2,231)

Placebo

(n = 2,239)

Neurologic

Headaches

24%

26%

Ear, nose, and throat

Throat and tonsil discomfort and pain

19%

20%

Nasal signs and symptoms

12%

13%

Ear, nose, and throat infections

2%

2%

Lower respiratory

Cough

17%

18%

Viral respiratory infections

3%

4%

Musculoskeletal

Muscle pain

8%

8%

Musculoskeletal pain

6%

6%

Arthralgia and articular rheumatism

2%

<1%

Endocrine and metabolic

Feeding problems (decreased or increased appetite and anorexia)

4%

4%

Gastrointestinal

Nausea and vomiting

2%

3%

Diarrhea

2%

2%

Non-site specific

Temperature regulation disturbances (fever and/or chills)

9%

10%

Malaise and fatigue

8%

8%

Postmarketing Experience

In addition to adverse events reported from clinical trials, the following events have been identified during postmarketing use of zanamivir (RELENZA). Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to zanamivir (RELENZA).

Allergic Reactions: Allergic or allergic-like reaction, including oropharyngeal edema [see Warnings and Precautions].

Psychiatric: Delirium, including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares [see Warnings and Precautions].

Cardiac: Arrhythmias, syncope.

Neurologic: Seizures.

Respiratory: Bronchospasm, dyspnea [see Warnings and Precautions].

Skin: Facial edema; rash, including serious cutaneous reactions; urticaria [see Warnings and Precautions].



REPORTS OF SUSPECTED RELENZA SIDE EFFECTS / ADVERSE REACTIONS

Below is a sample of reports where side effects / adverse reactions may be related to Relenza. The information is not vetted and should not be considered as verified clinical evidence.

Possible Relenza side effects / adverse reactions in 15 year old male

Reported by a physician from Greece on 2012-01-03

Patient: 15 year old male

Reactions: Rash Generalised, Hypotension, Anaphylactic Shock, Bronchospasm

Adverse event resulted in: death, hospitalization

Suspect drug(s):
Heparin

Relenza
    Indication: H1n1 Influenza
    Start date: 2011-03-10
    End date: 2011-03-13

Other drugs received by patient: Oseltamivir



Possible Relenza side effects / adverse reactions in 46 year old female

Reported by a health professional (non-physician/pharmacist) from France on 2012-01-12

Patient: 46 year old female

Reactions: Hypotension, Bradycardia

Adverse event resulted in: hospitalization

Suspect drug(s):
Lasix
    Start date: 2011-02-14

Relenza
    Start date: 2011-02-17
    End date: 2011-02-20



Possible Relenza side effects / adverse reactions in 9 year old male

Reported by a physician from Japan on 2012-01-23

Patient: 9 year old male

Reactions: Hallucination

Suspect drug(s):
Relenza



See index of all Relenza side effect reports >>

Drug label data at the top of this Page last updated: 2008-10-14

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