OpenClaim

Dextromethorphan Side Effects

The most commonly reported side effects of dextromethorphan include dizziness, diarrhoea, and nausea, based on 26,503 FDA adverse event reports from 2004 to 2025. 12.5% of reports found the drug to be ineffective.

Dextromethorphan side effects

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

1
Drug Ineffective12.5%3,310
2
Dizziness7.0%1,848
3
Diarrhoea5.5%1,446
4
Nausea4.5%1,197
5
Overdose3.9%1,041
6
Drug Abuse3.9%1,021
7
Toxicity To Various Agents3.6%964
8
Fatigue3.6%943
9
Accidental Overdose3.5%935
10
Headache3.2%835
11
Somnolence3.0%792
12
Off Label Use3.0%791
13
Feeling Abnormal2.9%758
14
Vomiting2.7%727
15
Insomnia2.7%726

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

Report severity

41.4%Serious10,964 reports
15.6%Hospitalizations4,126 reports
12.8%Fatal3,384 reports

Seriousness is determined by the reporter, not by OpenClaim.

Dextromethorphan drug interactions

Other drugs that appear in adverse event reports alongside dextromethorphan. 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
Guaifenesin21.5%5,710
2
Bupropion10.8%2,865
3
Quinidine9.4%2,500
4
Acetaminophen3.5%915
5
Diphenhydramine2.5%658
6
Oxycodone2.1%567
7
Pseudoephedrine1.6%436
8
Ibuprofen1.6%430
9
Sodium-oxybate1.6%420
10
Citalopram-hydrobromide1.6%419
11
Fluoxetine-hydrochloride1.5%397
12
Doxylamine-succinate1.4%379
13
Alprazolam1.4%367
14
Quetiapine-fumarate1.2%324
15
Lenalidomide1.2%322

Taken alongside

1
Acetaminophen8.7%2,312
2
Guaifenesin7.2%1,897
3
Ergocalciferol6.2%1,631
4
Albuterol5.6%1,481
5
Aspirin5.2%1,388
6
Levothyroxine-sodium4.5%1,194
7
Fluticasone4.5%1,190
8
Quinidine4.2%1,122
9
Omeprazole4.2%1,109
10
Gabapentin4.1%1,099
11
Ibuprofen4.0%1,073
12
Atorvastatin-calcium3.7%988
13
Amlodipine3.7%969
14
Furosemide3.4%903
15
Prednisone3.2%861

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 dextromethorphan side effects

52.9% of dextromethorphan adverse event reports involve female patients and 33.0% involve male patients. The largest age group is adult at 57%. These figures reflect who reports side effects, not underlying risk.

Sex

Female52.9%
Male33.0%
Unknown14.1%

Age group

< 21.1%
2–115.7%
12–173.7%
18–6456.8%
65+32.6%

What is dextromethorphan used for

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

Abdominal PainAbdominal Wall HaematomaAbnormal BehaviourAccidental Drug Intake By ChildAccidental ExposureAccidental Exposure To ProductAcute BronchitisAcute Myeloid LeukaemiaAcute TonsillitisAdjuvant TherapyAdverse EventAffect LabilityAffective DisorderAggressionAgitation

Showing 15 of 616 indications

Dextromethorphan brand names and reporting trend

Dextromethorphan is sold under brand names including Bromanate Dm, Delsym.

Brand names

Bromanate Dm7,714
Delsym866

Quarterly reports (20042025)

20052010201520202025

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

Taking dextromethorphan with another medication?

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