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Chlorothiazide Side Effects

The most commonly reported side effects of chlorothiazide include off label use, dyspnoea, and pyrexia, based on 1,576 FDA adverse event reports from 2004 to 2025. 4.4% of reports found the drug to be ineffective.

Chlorothiazide side effects

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

1
Off Label Use6.9%109
2
Dyspnoea5.6%88
3
Pyrexia4.9%78
4
Drug Ineffective4.4%69
5
Diarrhoea4.3%67
6
Pneumonia3.8%60
7
Hypotension3.7%58
8
Respiratory Failure3.5%55
9
Headache3.4%54
10
Vomiting3.2%51
11
Death3.2%50
12
Cough3.2%50
13
Pain2.9%46
14
Cardiac Arrest2.7%42
15
Fatigue2.6%41

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

Report severity

78.9%Serious1,243 reports
49.4%Hospitalizations778 reports
14.5%Fatal228 reports

Seriousness is determined by the reporter, not by OpenClaim.

Chlorothiazide drug interactions

Other drugs that appear in adverse event reports alongside chlorothiazide. 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
Bosentan9.8%154
2
Palivizumab8.5%134
3
Furosemide4.1%65
4
Treprostinil3.6%56
5
Ambrisentan2.9%45
6
Adalimumab2.2%34
7
Sildenafil-citrate2.0%31
8
Omeprazole1.9%30
9
Vancomycin1.7%27
10
Macitentan1.7%27
11
Lenalidomide1.4%22
12
Dexamethasone1.3%21
13
Acetaminophen1.3%21
14
Tobramycin1.3%20
15
Esomeprazole1.3%20

Taken alongside

1
Furosemide28.2%444
2
Spironolactone23.0%363
3
Albuterol19.0%299
4
Aspirin17.4%275
5
Acetaminophen16.4%258
6
Potassium-chloride15.7%247
7
Sildenafil-citrate13.7%216
8
Sodium-chloride12.1%190
9
Omeprazole11.2%177
10
Levothyroxine-sodium10.4%164
11
Fluticasone10.1%159
12
Amlodipine9.8%154
13
Famotidine9.5%149
14
Ergocalciferol9.3%147
15
Lorazepam8.9%141

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 chlorothiazide side effects

48.6% of chlorothiazide adverse event reports involve female patients and 46.2% involve male patients. The largest age group is elderly at 29%. These figures reflect who reports side effects, not underlying risk.

Sex

Female48.6%
Male46.2%
Unknown5.2%

Age group

< 225.5%
2–1114.1%
12–173.7%
18–6427.6%
65+29.0%

What is chlorothiazide used for

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

Alveolar Capillary DysplasiaAntiplatelet TherapyAcute Kidney InjuryBladder DisorderBlood Calcium AbnormalBlood PressureBlood Pressure AbnormalBlood Pressure IncreasedBlood Pressure ManagementBlood Pressure MeasurementBronchopulmonary DysplasiaBudd-chiari SyndromeBlood Pressure AbnormalBlood Pressure MeasurementBronchopulmonary Dysplasia

Showing 15 of 93 indications

Chlorothiazide brand names and reporting trend

Chlorothiazide is sold under brand names including Methyldopa And Chlorothiazide, Chlorothiazide Sodium.

Brand names

Methyldopa And Chlorothiazide1,179
Chlorothiazide Sodium60

Quarterly reports (20042025)

20052010201520202025

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

Taking chlorothiazide with another medication?

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