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Cyanocobalamin Side Effects

The most commonly reported side effects of cyanocobalamin include fatigue, nausea, and diarrhoea, based on 149,215 FDA adverse event reports from 2004 to 2025. 5.8% of reports found the drug to be ineffective.

Cyanocobalamin side effects

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

1
Fatigue9.6%14,370
2
Nausea6.9%10,242
3
Diarrhoea6.8%10,184
4
Headache5.9%8,750
5
Off Label Use5.8%8,655
6
Drug Ineffective5.8%8,608
7
Pain5.2%7,758
8
Dyspnoea4.9%7,274
9
Dizziness4.7%7,067
10
Asthenia4.6%6,809
11
Fall4.5%6,697
12
Arthralgia4.4%6,589
13
Vomiting3.7%5,549
14
Malaise3.6%5,363
15
Death3.5%5,233

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

Report severity

63.4%Serious94,606 reports
31.0%Hospitalizations46,221 reports
7.6%Fatal11,401 reports

Seriousness is determined by the reporter, not by OpenClaim.

Cyanocobalamin drug interactions

Other drugs that appear in adverse event reports alongside cyanocobalamin. 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
Lenalidomide7.6%11,312
2
Adalimumab5.8%8,608
3
Sodium-oxybate3.3%4,894
4
Infliximab2.3%3,364
5
Prednisone2.1%3,079
6
Pemetrexed1.9%2,858
7
Etanercept1.9%2,796
8
Dupilumab1.8%2,732
9
Pomalidomide1.8%2,675
10
Dalfampridine1.8%2,652
11
Rituximab1.7%2,548
12
Methotrexate1.7%2,522
13
Pregabalin1.6%2,393
14
Vedolizumab1.6%2,380
15
Pantoprazole-sodium1.6%2,329

Taken alongside

1
Ergocalciferol44.4%66,279
2
Aspirin23.5%34,997
3
Acetaminophen21.7%32,341
4
Levothyroxine-sodium18.2%27,091
5
Folic-acid18.0%26,870
6
Ascorbic-acid14.9%22,200
7
Calcium14.5%21,589
8
Omeprazole14.3%21,344
9
Atorvastatin-calcium13.2%19,681
10
Gabapentin13.1%19,586
11
Furosemide11.9%17,806
12
Metoprolol11.8%17,614
13
Albuterol11.6%17,243
14
Amlodipine11.3%16,917
15
Pantoprazole-sodium11.2%16,746

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 cyanocobalamin side effects

61.5% of cyanocobalamin adverse event reports involve female patients and 32.2% involve male patients. The largest age group is elderly at 52%. These figures reflect who reports side effects, not underlying risk.

Sex

Female61.5%
Male32.2%
Unknown6.2%

Age group

< 20.2%
2–110.3%
12–170.4%
18–6446.8%
65+52.3%

What is cyanocobalamin used for

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

Abdominal DiscomfortAchlorhydriaAcute Disseminated EncephalomyelitisAcute Graft Versus Host DiseaseAcute Lymphocytic LeukaemiaAcute Myeloid LeukaemiaAddison^s DiseaseAdenine Phosphoribosyl Transferase DeficiencyAdjuvant TherapyAdverse EventAffective DisorderAge-related Macular DegenerationAlcohol AbuseAlcohol DetoxificationAlcoholic Seizure

Showing 15 of 1,059 indications

Cyanocobalamin brand names and reporting trend

Cyanocobalamin is sold under brand names including Ruvite, Dicopac Kit.

Brand names

Ruvite150,185
Dicopac Kit540

Quarterly reports (20042025)

20052010201520202025

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

Taking cyanocobalamin with another medication?

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