MedDRA preferred term

Rebound effect: adverse event reports recording this term

11,184 reports to FDA record it, 2004–2026; 0.1% of the database.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

11,184
reports recording the term: 0.1% of all reports; 1,920
reports, 12 months to June 2026: 1,708 in the 12 months before; 62.1%
marked serious by the reporter: 57.4% across all reports; 2.4%
record death among outcomes, as reported: 9.1% across all reports

"Rebound effect" is a MedDRA preferred term recorded in 11,184 adverse event reports received by FDA, 0.1% of the database, from January 2004 to June 2026. The term is chosen by whoever codes the report to match what the reporter described.

1,920 reports recorded it in the 12 months to June 2026, up 12% from 1,708 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Of reports recording this term, 62.1% are marked serious, 2.4% include death among the outcomes and 15.7% include hospitalisation, as reported.

The drugs listed most often as suspect products in those reports are Dupixent, Prilosec OTC and Prilosec. That order mostly follows how many reports each drug has overall; the table also gives the term's share within each drug's own reports. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Drugs listed as suspect products in these reports

Drug	Class	Reports with this term	Share of the drug's own reports
Dupixent	Interleukin-4 receptor alpha antagonist	2,462	0.5%
Prilosec OTC	Proton pump inhibitor	1,977	8.1%
Prilosec	Proton pump inhibitor	1,631	3.9%
Prevacid	Proton pump inhibitor	1,430	3.6%
Nexium	Proton pump inhibitor	1,309	1.5%
Prednisone	Corticosteroid	945	0.5%
Nexium 24HR	Proton pump inhibitor	940	3.4%
Pantoprazole sodium	Proton pump inhibitor	893	2%
Prevacid 24 HR	Proton pump inhibitor	574	2.9%
Dexilant	Proton pump inhibitor	572	2.4%
Prolia	RANK ligand inhibitor	424	0.3%
Prednisolone	Corticosteroid	384	0.4%
Paxlovid	—	339	0.6%
Gilenya	Sphingosine 1-phosphate receptor modulator	293	0.4%
Methotrexate	Folate analog metabolic inhibitor	289	0.1%
Methylprednisolone	Corticosteroid	252	0.5%
Mycophenolate mofetil	Antimetabolite immunosuppressant	245	0.3%
Omeprazole	Proton pump inhibitor	210	0.3%
Rituximab	CD20-directed cytolytic antibody	159	0.1%
Cyclosporine	Calcineurin inhibitor immunosuppressant	138	0.4%
Mirvaso	alpha-Adrenergic agonist	136	14.7%
Azathioprine	Purine antimetabolite	132	0.4%
Dexamethasone	Corticosteroid	113	0.1%
Tacrolimus	Calcineurin inhibitor immunosuppressant	108	0.1%
Mirvaso Topical Gel 0 33%	—	107	25.7%

Drugs with a page on this site, ordered by the number of their reports recording this term. The last column is the term's share within that drug's own reports, against 0.1% across the whole database. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

By pharmacologic class

Class	Reports with this term	Share of class reports	Median drug in class
Proton pump inhibitor	9,782	2%	0.3%
Interleukin-4 receptor alpha antagonist	2,499	0.5%	0.4%
Corticosteroid	1,811	0.2%	0%
RANK ligand inhibitor	501	0.3%	0.3%
Atypical antipsychotic	461	0.1%	0%
Sphingosine 1-phosphate receptor modulator	387	0.4%	0%
Folate analog metabolic inhibitor	310	0.1%	0%
Antimetabolite immunosuppressant	270	0.2%	0.1%
Calcineurin inhibitor immunosuppressant	246	0.1%	0%
Benzodiazepine	214	0.1%	0%

Classes ordered by count. Class shares follow the class's overall report volume as much as anything else.

Patients in these reports

Patient age

Under 20.4%47

2 to 113.2%357

12 to 172.8%311

18 to 4418.7%2,092

45 to 6419.7%2,205

65 to 748.8%988

75 and over4.7%521

Age not given41.7%4,663

Patient sex

Female44.3%4,959

Male30.2%3,381

Not given25.4%2,844

Grey bar: all 20,646,523 reports in the database. 72.6% of these reports give the United States as the country.

Questions about "Rebound effect"

What does "Rebound effect" mean in an adverse event report?

It is a MedDRA preferred term, the dictionary FDA uses to code what a reporter described. The report's own description is not published by openFDA and is not shown here.

How many reports record rebound effect?

11,184 reports through June 2026 (0.1% of all reports), 1,920 of them in the latest 12 months.

Which drugs appear most often in these reports?

Dupixent (2,462), Prilosec OTC (1,977), Prilosec (1,631), Prevacid (1,430) and Nexium (1,309). Drugs with many reports overall lead almost every term's list. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Does a drug appearing here mean it was responsible for this reaction?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

I have this symptom. What should I do?

This site cannot assess anyone. A pharmacist or clinician can; for an emergency, call the local emergency number. Nothing on this page is medical advice.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. Terms are pooled across spelling and capitalisation variants of one MedDRA preferred term. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.