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Zanamivir Side Effects

The most commonly reported side effects of zanamivir include overdose, abnormal behaviour, and drug exposure during pregnancy, based on 2,539 FDA adverse event reports from 2004 to 2025.

Zanamivir side effects

Percentages show how often each reaction appears relative to total reports for zanamivir.

1
Overdose15.4%392
2
Abnormal Behaviour13.9%353
3
Drug Exposure During Pregnancy9.6%244
4
Hallucination5.9%149
5
Drug Exposure Via Breast Milk4.8%123
6
No Adverse Event4.6%116
7
Delirium4.2%106
8
Pyrexia2.7%68
9
Loss Of Consciousness2.6%67
10
Aggression2.0%52
11
Depressed Level Of Consciousness1.9%49
12
Abnormal Behaviour1.8%46
13
Vomiting1.7%43
14
Agitation1.7%43
15
Restlessness1.7%43

These are voluntary reports and do not establish that zanamivir caused these reactions.

Report severity

63.4%Serious1,610 reports
15.6%Hospitalizations396 reports
10.1%Fatal256 reports

Seriousness is determined by the reporter, not by OpenClaim.

Zanamivir drug interactions

Other drugs that appear in adverse event reports alongside zanamivir. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Oseltamivir-phosphate4.1%105
2
Trastuzumab1.2%31
3
Exemestane1.2%30
4
Letrozole1.2%30
5
Prednisone0.8%20
6
Ketamine-hydrochloride0.6%15
7
Cyclosporine0.6%14
8
Hyaluronidase0.6%14
9
Propofol0.5%12
10
Pantoprazole-sodium0.5%12
11
Rosuvastatin0.4%11
12
Azithromycin0.4%10
13
Ibuprofen0.4%10
14
Voriconazole0.4%10
15
Metoprolol0.4%10

Taken alongside

1
Acetaminophen4.8%121
2
Oseltamivir-phosphate4.6%117
3
Clarithromycin3.6%92
4
Meropenem3.4%86
5
Amoxicillin2.6%66
6
Vancomycin2.3%59
7
Linezolid2.3%58
8
Furosemide2.1%53
9
Ciprofloxacin1.9%48
10
Lansoprazole1.9%48
11
Gabapentin1.8%45
12
Levothyroxine-sodium1.7%44
13
Acyclovir1.6%41
14
Naproxen1.6%41
15
Metronidazole1.5%39

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports zanamivir side effects

41.7% of zanamivir adverse event reports involve female patients and 38.6% involve male patients. The largest age group is adult at 37%. These figures reflect who reports side effects, not underlying risk.

Sex

Female41.7%
Male38.6%
Unknown19.8%

Age group

< 23.4%
2–1132.6%
12–1720.9%
18–6436.9%
65+6.2%

What is zanamivir used for

Conditions and purposes for which patients were taking zanamivir when the adverse event was reported.

Acute Respiratory Distress SyndromeAnticoagulant TherapyAntiviral ProphylaxisAntiviral TreatmentBacteraemiaDrug Exposure During PregnancyDrug Exposure Via Breast MilkDrug Use For Unknown IndicationDyspnoeaExposure To Communicable DiseaseFoetal Exposure During PregnancyH1n1 InfluenzaH1n1 InfluenzaIll-defined DisorderImmunisation

Showing 15 of 40 indications

Zanamivir brand names and reporting trend

Zanamivir is sold under the brand name Relenza.

Brand names

Relenza468

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking zanamivir with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.