Drug effect decreased adverse event reports that record this term
- Kind of term
- MedDRA preferred term
- Plain meaning
- the medicine had less effect
What a report is
A report is not proof that the drug was the cause of the event.
FDA says:
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.
Source: openFDA, Drug Adverse Event Overview, section "Responsible use of the data". The site read the page on . The data have the reports that FDA received through .
FDA also says:
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 has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
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.
Source: openFDA, Response of the drug event API (meta.disclaimer). The site read the page on .
Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.
Reports on file
From January 2004 to March 2019, FDA received 53,762 adverse event reports that record the MedDRA preferred term Drug effect decreased. In plain words, the term means: the medicine had less effect. The person who codes a report selects the term that agrees best with the description of the reporter.
FDA received 0 reports in the 12 months to June 2026 and 0 in the 12 months before. FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.
Reports for patients 75 and over were 4.5% of the reports that record this term and 9.5% of all drug reports.
The number of people who use the product is not in the data. A count is not a rate.
MedDRA
The Medical Dictionary for Regulatory Activities. The person who codes a report selects the preferred term that agrees best with the description of the reporter. FDA does not publish the description.
Plain meaning
The medicine had less effect. The words are from the fixed dictionary of this site. They add nothing to a report.
Data version
openFDA FAERS release of 29 Oct 2026. Reports received through 30 Jun 2026.
Drugs in these reports
The table has the 92 drug pages with 100 or more reports that record this term. The rows are in order of name. A drug page with fewer reports for this term is not in the table. The counts are the counts that the site keeps for each reaction term, and a count can be lower than the count of FDA.
FDA says:
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.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .
| Drug | Class | Reports with this term |
|---|---|---|
| Actemra | Interleukin-6 receptor antagonist | 569 |
| Adderall | Central nervous system stimulant | 165 |
| Advair Diskus | Corticosteroid | 147 |
| Advil | Nonsteroidal anti-inflammatory drug | 113 |
| Aimovig | 168 | |
| Alprazolam | Benzodiazepine | 119 |
| Ampyra | Potassium channel blocker | 433 |
| Arava | Antirheumatic agent | 319 |
| Avonex | Interferon beta | 164 |
| Belviq | 111 | |
| Breo Ellipta | Corticosteroid | 104 |
| Butrans | Partial opioid agonist | 1,659 |
| Byetta | GLP-1 receptor agonist | 1,502 |
| Celebrex | Nonsteroidal anti-inflammatory drug | 312 |
| Chantix | Partial cholinergic nicotinic agonist | 134 |
| Cimzia | Tumor necrosis factor blocker | 324 |
| Claritin | 480 | |
| Claritin Chewable | 274 | |
| Claritin-D 24 Hour | 277 | |
| Claritin-D-24 | 234 | |
| Clonazepam | Benzodiazepine | 118 |
| Combivent | 164 | |
| Concerta | Central nervous system stimulant | 132 |
| Coricidin Hbp Cold and Flu | 160 | |
| Cosentyx | Interleukin-17A antagonist | 416 |
| Cymbalta | 319 | |
| Daytrana | Central nervous system stimulant | 176 |
| Desvenlafaxine succinate | Serotonin and norepinephrine reuptake inhibitor | 195 |
| Detrol | Cholinergic muscarinic antagonist | 127 |
| Duragesic | 166 | |
| Duragesic-100 | 283 | |
| Dysport | Acetylcholine release inhibitor | 143 |
| Effexor | Serotonin and norepinephrine reuptake inhibitor | 167 |
| Enbrel | Tumor necrosis factor blocker | 7,560 |
| Fentanyl | Opioid agonist | 366 |
| Fentanyl Transdermal System | 1,106 | |
| Fentanyl-100 | 229 | |
| Gabapentin | Anti-epileptic agent | 183 |
| Heparin sodium | Anti-coagulant | 163 |
| Humalog | Insulin analog | 104 |
| Humira | 5,497 | |
| Hydroxychloroquine | Antimalarial | 208 |
| Hysingla ER | Opioid agonist | 235 |
| Ingrezza | Vesicular monoamine transporter 2 inhibitor | 178 |
| Invega Sustenna | Atypical antipsychotic | 258 |
| Invega Trinza | Atypical antipsychotic | 125 |
| Leflunomide | Antirheumatic agent | 213 |
| Lipitor | HMG-CoA reductase inhibitor | 133 |
| Lunesta | 219 | |
| Lyrica | 470 | |
| Methotrexate | Folate analog metabolic inhibitor | 1,313 |
| Methotrexate sodium | Folate analog metabolic inhibitor | 366 |
| Methylphenidate hydrochloride | Central nervous system stimulant | 108 |
| MiraLAX | Osmotic laxative | 445 |
| Morphine sulfate | Opioid agonist | 127 |
| Mtx | 103 | |
| Neurontin | 187 | |
| Nexium | Proton pump inhibitor | 300 |
| Nplate | Thrombopoietin receptor agonist | 114 |
| Nucynta | Opioid agonist | 102 |
| Nuvigil | 113 | |
| Omeprazole | Proton pump inhibitor | 137 |
| Opana Er | 229 | |
| Orencia | Selective T cell costimulation modulator | 544 |
| Otezla | Phosphodiesterase 4 inhibitor | 707 |
| Oxycodone hydrochloride | Opioid agonist | 105 |
| OxyContin | Opioid agonist | 1,216 |
| Oxytrol for Women | Cholinergic muscarinic antagonist | 557 |
| Plaquenil | Antimalarial | 425 |
| Polyethylene glycol 3350 | Osmotic laxative | 125 |
| Prednisone | Corticosteroid | 363 |
| Prilosec | Proton pump inhibitor | 118 |
| Proair Hfa | 303 | |
| Remicade | Tumor necrosis factor blocker | 1,375 |
| Revlimid | Thalidomide analog | 124 |
| Rituxan | CD20-directed cytolytic antibody | 368 |
| Seroquel | Atypical antipsychotic | 169 |
| Simponi | Tumor necrosis factor blocker | 549 |
| Stelara | Interleukin-12 antagonist | 465 |
| Strattera | Norepinephrine reuptake inhibitor | 189 |
| Sulfasalazine | Aminosalicylate | 335 |
| Symbicort | Corticosteroid | 145 |
| Tecfidera | 163 | |
| Tiotropium bromide | Anticholinergic | 217 |
| Tysabri | Integrin receptor antagonist | 1,316 |
| Ventolin Hfa | beta2-Adrenergic agonist | 111 |
| Viagra | Phosphodiesterase 5 inhibitor | 498 |
| Vyvanse | Central nervous system stimulant | 733 |
| Xeljanz | Janus kinase inhibitor | 426 |
| Xolair | Anti-IgE | 112 |
| Zoloft | Serotonin reuptake inhibitor | 140 |
| Zytiga | Cytochrome P450 17A1 inhibitor | 116 |
The page of each drug has the count of each reaction term in its reaction lookup.
Drug classes in these reports
The table has the 34 pharmacologic classes with 250 or more reports that record this term. The rows are in order of name.
FDA says:
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.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .
A class with many reports in all has many reports for almost every term.
Reports by month
FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.
Patients in these reports
| Age | Reports | Share | Share as a bar |
|---|---|---|---|
| Under 2 | 64 | 0.1% | |
| 2 to 11 | 839 | 1.6% | |
| 12 to 17 | 610 | 1.1% | |
| 18 to 44 | 6,579 | 12.2% | |
| 45 to 64 | 12,163 | 22.6% | |
| 65 to 74 | 4,337 | 8.1% | |
| 75 and over | 2,423 | 4.5% | |
| Age not given | 26,747 | 49.8% |
| Sex | Reports | Share | Share as a bar |
|---|---|---|---|
| Female | 30,109 | 56% | |
| Male | 19,887 | 37% | |
| Unknown or not given | 3,766 | 7% |
Age and sex are as the report gives them. 86.4% of these reports give the United States as the country.
Terms near this one
- Drug dispensing error
- Drug diversion
- Drug dose omission
- Drug dose omission by device
- Drug effect incomplete
- Drug effect less than expected
- Drug effective for unapproved indication
- Drug eruption
These are the next terms in the A to Z list. The links are for navigation.
Official pages
- MedWatch Online Voluntary Reporting FormThe online form of FDA for a voluntary report.
- MedWatch: The FDA Safety Information and Adverse Event Reporting ProgramThe page of the FDA program that receives reports about drugs and devices.
- FDA Adverse Event Monitoring System (AEMS) Public DashboardThe public dashboard of FDA for adverse event reports on drugs and biologics.
The site checked these addresses on . The links open in a new tab.
Cite this page
Reported Reactions. Drug effect decreased: adverse event reports that record this term. https://reportedreactions.com/reaction/drug-effect-decreased/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of . Reports received through .
Where the data come from
The counts come from the openFDA Drug Adverse Event (FAERS) bulk files, release of 29 Oct 2026. The files have the reports that FDA received through 30 Jun 2026. A drug name is the name on the report. The site matches it to a brand name or a generic name of the National Drug Code Directory of 2 Nov 2026. A class is the pharmacologic class (EPC) of the FDA label.
The count has the reports with each spelling of one MedDRA preferred term. The site does not publish a report narrative, a lot number, a detail of a patient or the identity of a reporter. The record of FDA is the authority. See how the site counts reports, the data sources and the corrections page.
Questions
What does Drug effect decreased mean in an adverse event report?
In plain words: the medicine had less effect. It is a MedDRA preferred term. FDA codes the description of a reporter with the MedDRA dictionary. The openFDA files do not have the description itself, and this site does not show it.
Does a drug in the table mean that the drug was responsible for this reaction?
No. FDA says:
No individual drug is connected to any individual reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
When a report lists multiple drugs and multiple reactions, there is no way to conclude from the data therein that a given drug is responsible for a given reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
What does this page tell a person who has this symptom?
This page gives counts of reports. It cannot assess a person. A pharmacist or a clinician can assess a person.
If this is a medical emergency, please call 911.
Source: FDA, MedWatch Online Voluntary Reporting Form. The site read the page on .