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Methylene Side Effects

The most commonly reported side effects of methylene include serotonin syndrome, drug interaction, and hypotension, based on 1,583 FDA adverse event reports from 2004 to 2025. 17.9% of reports found the drug to be ineffective.

Methylene side effects

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

1
Serotonin Syndrome27.2%430
2
Drug Interaction20.3%321
3
Drug Ineffective17.9%284
4
Hypotension12.8%202
5
Off Label Use11.0%174
6
Toxicity To Various Agents8.5%135
7
Overdose6.4%102
8
Intentional Overdose5.9%94
9
Serotonin Syndrome4.8%76
10
Toxic Encephalopathy4.7%75
11
Drug Interaction4.6%73
12
Blood Creatine Phosphokinase Increased4.4%70
13
Acute Kidney Injury4.4%70
14
Vasoplegia Syndrome4.4%69
15
Alanine Aminotransferase Increased4.2%67

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

Report severity

93.7%Serious1,484 reports
59.4%Hospitalizations940 reports
15.2%Fatal240 reports

Seriousness is determined by the reporter, not by OpenClaim.

Methylene drug interactions

Other drugs that appear in adverse event reports alongside methylene. 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
Epinephrine19.3%305
2
Vasopressin12.9%204
3
Amlodipine9.6%152
4
Fentanyl7.4%117
5
Fluoxetine-hydrochloride6.3%100
6
Paroxetine6.2%98
7
Phenylephrine5.6%88
8
Propofol5.3%84
9
Quetiapine-fumarate5.1%80
10
Citalopram-hydrobromide4.2%67
11
Meperidine-hydrochloride4.0%63
12
Glucagon4.0%63
13
Rocuronium-bromide3.9%61
14
Norepinephrine-bitartrate3.8%60
15
Sodium-bicarbonate3.7%58

Taken alongside

1
Propofol10.5%166
2
Epinephrine9.6%152
3
Vasopressin7.3%116
4
Dexamethasone6.4%101
5
Fentanyl6.1%97
6
Acetaminophen5.6%89
7
Sevoflurane5.5%87
8
Midazolam5.3%84
9
Rocuronium-bromide4.9%77
10
Ondansetron4.6%73
11
Aspirin4.1%65
12
Furosemide3.9%61
13
Levothyroxine-sodium3.7%59
14
Insulin3.7%58
15
Vancomycin3.5%56

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 methylene side effects

51.2% of methylene adverse event reports involve female patients and 39.5% involve male patients. The largest age group is adult at 68%. These figures reflect who reports side effects, not underlying risk.

Sex

Female51.2%
Male39.5%
Unknown9.3%

Age group

< 23.3%
2–111.4%
12–174.8%
18–6468.5%
65+22.1%

What is methylene used for

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

Adverse EventAnaemiaArthritis ReactiveAnaemiaAnaesthesiaAnaesthesia ProcedureAnaphylactic ShockAnxietyBiopsyBiopsy Lymph GlandBladder Tumour ResectionBlood MethaemoglobinBlood Pressure Systolic DecreasedBradycardiaBreast Cancer

Showing 15 of 177 indications

Methylene brand names and reporting trend

Methylene is sold under the brand name Methylene Blue.

Brand names

Methylene Blue1,756

Quarterly reports (20042025)

20052010201520202025

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

Taking methylene with another medication?

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