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Selenomethionine Side Effects

The most commonly reported side effects of selenomethionine include fatigue, headache, and diarrhoea, based on 400 FDA adverse event reports from 2004 to 2025.

Selenomethionine side effects

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

1
Fatigue10.0%40
2
Headache8.5%34
3
Diarrhoea8.5%34
4
Vomiting8.3%33
5
Nausea7.2%29
6
Fall7.2%29
7
Pneumonia7.0%28
8
Pyrexia7.0%28
9
Condition Aggravated6.8%27
10
General Physical Health Deterioration6.3%25
11
Anaemia6.0%24
12
Weight Decreased6.0%24
13
Malaise6.0%24
14
Infection5.8%23
15
Back Pain5.5%22

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

Report severity

87.3%Serious349 reports
50.7%Hospitalizations203 reports
15.3%Fatal61 reports

Seriousness is determined by the reporter, not by OpenClaim.

Selenomethionine drug interactions

Other drugs that appear in adverse event reports alongside selenomethionine. 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
Betaine7.5%30
2
Prednisone6.3%25
3
Tacrolimus4.8%19
4
Ocrelizumab4.5%18
5
Risperidone4.0%16
6
Sulfamethoxazole4.0%16
7
Trimethoprim4.0%16
8
Olanzapine3.8%15
9
Torsemide3.8%15
10
Azithromycin3.3%13
11
Azathioprine3.3%13
12
Sodium-oxybate3.0%12
13
Methotrexate2.8%11
14
Metformin2.8%11
15
Teduglutide2.8%11

Taken alongside

1
Aspirin15.8%63
2
Ergocalciferol13.8%55
3
Calcium13.5%54
4
Folic-acid13.0%52
5
Acetaminophen12.8%51
6
Pantoprazole-sodium12.5%50
7
Furosemide11.0%44
8
Cyanocobalamin10.8%43
9
Ramipril9.8%39
10
Cholecalciferol9.5%38
11
Magnesium-acetate-tetrahydrate9.5%38
12
Levothyroxine-sodium8.8%35
13
Metoprolol8.8%35
14
Gabapentin8.3%33
15
Ascorbic-acid8.3%33

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 selenomethionine side effects

53.5% of selenomethionine adverse event reports involve female patients and 37.5% involve male patients. The largest age group is elderly at 51%. These figures reflect who reports side effects, not underlying risk.

Sex

Female53.5%
Male37.5%
Unknown9.0%

Age group

< 23.2%
2–112.3%
12–171.0%
18–6442.5%
65+51.0%

What is selenomethionine used for

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

Alanine Aminotransferase IncreasedAlveolar ProteinosisBladder DisorderBacteriuriaBody Fat DisorderCovid-19Cystitis NoninfectiveDrug Exposure During PregnancyDrug TherapyDrug Use For Unknown IndicationDiabetes MellitusDiffuse Large B-cell Lymphoma Stage IvGastric DisorderHepatic Function AbnormalHyperglycaemia

Showing 15 of 50 indications

Selenomethionine brand names and reporting trend

Selenomethionine is sold under the brand name Sethotope.

Brand names

Sethotope417

Quarterly reports (20042025)

2005201520202025

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

Taking selenomethionine with another medication?

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