OpenClaim

Clemastine Side Effects

The most commonly reported side effects of clemastine include dyspnoea, pyrexia, and off label use, based on 4,183 FDA adverse event reports from 2004 to 2025. 3.9% of reports found the drug to be ineffective.

Clemastine side effects

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

1
Dyspnoea8.1%339
2
Pyrexia6.2%259
3
Off Label Use5.8%244
4
Erythema5.6%233
5
Nausea5.3%221
6
Diarrhoea4.6%191
7
Pneumonia4.3%179
8
Anaemia4.1%172
9
Fatigue4.0%169
10
Vomiting3.9%164
11
Drug Ineffective3.9%164
12
Neutropenia3.8%158
13
Rash3.6%150
14
Febrile Neutropenia3.2%135
15
Cytokine Release Syndrome3.2%132

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

Report severity

93.3%Serious3,901 reports
55.9%Hospitalizations2,338 reports
13.8%Fatal577 reports

Seriousness is determined by the reporter, not by OpenClaim.

Clemastine drug interactions

Other drugs that appear in adverse event reports alongside clemastine. 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
Dexamethasone13.4%562
2
Paclitaxel12.4%518
3
Carboplatin12.1%506
4
Rituximab12.0%501
5
Cyclophosphamide10.9%454
6
Doxorubicin-hydrochloride8.4%350
7
Prednisone6.7%280
8
Vincristine-sulfate6.3%263
9
Lenalidomide5.2%216
10
Epcoritamab-bysp4.6%194
11
Isatuximab-irfc4.2%176
12
Carfilzomib4.1%173
13
Docetaxel3.7%155
14
Methylprednisolone3.7%154
15
Ocrelizumab3.7%153

Taken alongside

1
Acetaminophen37.7%1,578
2
Dexamethasone27.4%1,145
3
Ondansetron19.6%821
4
Pantoprazole-sodium14.9%623
5
Ranitidine14.3%599
6
Acyclovir12.6%528
7
Prednisolone12.4%517
8
Omeprazole11.5%481
9
Allopurinol11.5%480
10
Methylprednisolone11.3%473
11
Metoclopramide-hydrochloride10.2%427
12
Furosemide10.0%420
13
Hydrocortisone8.3%349
14
Granisetron8.2%344
15
Aspirin7.7%320

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 clemastine side effects

53.0% of clemastine adverse event reports involve female patients and 37.4% involve male patients. The largest age group is adult at 54%. These figures reflect who reports side effects, not underlying risk.

Sex

Female53.0%
Male37.4%
Unknown9.7%

Age group

< 20.6%
2–113.4%
12–172.4%
18–6453.8%
65+39.8%

What is clemastine used for

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

AbscessAcute Myeloid LeukaemiaAdult T-cell Lymphoma/leukaemiaAdverse EventAgranulocytosisAllergic ReactionAllergy ProphylaxisAllergy TestAltered State Of ConsciousnessAnaemiaAnaphylactic ReactionAnaphylactic ShockAnaphylaxis ProphylaxisAngioedemaAntiallergic Therapy

Showing 15 of 238 indications

Clemastine brand names and reporting trend

Clemastine is sold under the brand name Tavist.

Brand names

Tavist459

Quarterly reports (20042025)

20052010201520202025

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

Taking clemastine with another medication?

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