Reported Reactions

Drugs › Opioid antagonist

Brand name · Naldemedine

Symproic: adverse event reports filed with FDA

548 reports list it as a suspect or interacting product, 2017–2026. Class: Opioid antagonist.

548
reports as suspect product
0% of all reports · about 60 a year
13
reports, 12 months to June 2026
30 in the 12 months before
47.3%
marked serious by the reporter
62.4% across the class
25.5%
record death among outcomes, as reported
140 reports · not verified by FDA

Between June 2017 and April 2026, 548 adverse event reports received by FDA list the brand name Symproic (naldemedine) as a suspect or interacting product. Reports that mention it only as a concomitant medication (855) are left out of every figure here.

In the 12 months to June 2026, 13 reports listed it, down 57% from 30 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 60 reports a year and 0% of the 20,646,523 reports in the database, and 1.8% of the reports for the opioid antagonist class. How many people take it is not in the data, so a count is not a rate of occurrence.

The reactions recorded most often are diarrhoea (20.3%), drug ineffective (14.6%) and abdominal pain (10.4%). A report can list several reactions, so shares add to more than 100%; 112 different terms appear across these reports. Diarrhoea is recorded in 20.3% of these reports, a larger share than in the median opioid antagonist drug (2.2%).

47.3% of the reports are marked serious by the reporter (62.4% across the class); 25.5% record death among the outcomes and 15.1% record hospitalisation, as reported. 49.5% of the reports came from consumers, and the largest patient age group is 45 to 64 (15.1%). 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

01019Jul 2021: 1Aug 2021: 0Sep 2021: 0Oct 2021: 0Nov 2021: 0Dec 2021: 02022Jan 2022: 1Feb 2022: 3Mar 2022: 19Apr 2022: 3May 2022: 2Jun 2022: 3Jul 2022: 2Aug 2022: 0Sep 2022: 5Oct 2022: 0Nov 2022: 1Dec 2022: 42023Jan 2023: 2Feb 2023: 1Mar 2023: 5Apr 2023: 9May 2023: 2Jun 2023: 3Jul 2023: 3Aug 2023: 3Sep 2023: 3Oct 2023: 1Nov 2023: 1Dec 2023: 12024Jan 2024: 0Feb 2024: 1Mar 2024: 8Apr 2024: 0May 2024: 2Jun 2024: 4Jul 2024: 4Aug 2024: 0Sep 2024: 2Oct 2024: 0Nov 2024: 5Dec 2024: 12025Jan 2025: 1Feb 2025: 2Mar 2025: 2Apr 2025: 9May 2025: 1Jun 2025: 3Jul 2025: 2Aug 2025: 1Sep 2025: 2Oct 2025: 2Nov 2025: 3Dec 2025: 12026Jan 2026: 0Feb 2026: 0Mar 2026: 1Apr 2026: 1May 2026: 0Jun 2026: 0

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

01533062017: 5520172018: 30620182019: 4420192020: 720202021: 120212022: 4320222023: 3420232024: 2720242025: 2920252026: 22026

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Symproic reports recording the termmedian drug in opioid antagonist

  1. Diarrhoealoose or frequent stools20.3%111
  2. Drug ineffectivethe medicine did not work as expected14.6%80
  3. Abdominal painstomach or belly pain10.4%57
  4. Nauseafeeling sick6.4%35
  5. Constipationconstipation5.7%31
  6. Neoplasm malignanta cancer, type not specified4%22
  7. Vomitingbeing sick3.6%20
  8. Drug withdrawal syndromesymptoms on stopping a medicine3.1%17
  9. Lung neoplasm malignantlung cancer2.7%15
  10. Abdominal pain upperupper stomach pain2.2%12
  11. Hyperhidrosisexcessive sweating2%11
  12. Abdominal discomfortstomach discomfort1.6%9
  13. Abdominal distensiona bloated abdomen1.6%9
  14. Deaththe patient died; cause not stated by this term1.6%9
  15. Deliriumsudden confusion1.6%9
  16. Dizzinesslight-headedness or unsteadiness1.5%8
  17. Muscle spasmsmuscle cramps1.5%8
  18. Electrocardiogram QT prolongeda QT prolongation on the ECG1.3%7
  19. Drug interactionan interaction between medicines1.1%6
  20. Dehydrationdehydration0.9%5
  21. No adverse eventno adverse event was reported0.9%5
  22. Unevaluable eventthe event could not be assessed0.9%5
  23. Breast cancerbreast cancer0.7%4
  24. Chillschills or shivering0.7%4
  25. Flatulencewind0.7%4
  26. Hyperkalaemiahigh blood potassium0.7%4
  27. Ileusthe bowel stopped moving0.7%4

Top 30 of 112 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 10 drugs in the opioid antagonist class; it describes the reports, not the patients. 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."

Outcomes recorded

Death25.5%140
Life-threatening3.8%21
Hospitalisation (initial or prolonged)15.1%83
Disability0%0
Congenital anomaly0%0
Other serious19.7%108
Not serious52.7%289

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 31,239 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 20%0
2 to 110%0
12 to 170%0
18 to 443.8%21
45 to 6415.1%83
65 to 7411.1%61
75 and over11.9%65
Age not given58%318

Patient sex

Female45.4%249
Male37.8%207
Not given16.8%92

Who reported

Physician32.8%180
Pharmacist13.5%74
Other health professional4%22
Lawyer0%0
Consumer or non-health professional49.5%271
Not given0.2%1

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 54.7% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Constipation25746.9%

The indication field is filled in by the reporter and is often blank; shares are of all 548 reports.

In context

MeasureSymproicOpioid antagonistAll reports
Reports as suspect product54831,23920,646,523
Share of that pool—1.8%0%
Reports, latest 12 months13—1,332,454
Marked serious47.3%62.4%57.4%
Death recorded among outcomes, per 1,000 reports2558791
Hospitalisation recorded, per 1,000 reports151204213
Consumer-filed share49.5%48.6%45.8%
Top term, share of reportsDiarrhoea 20.3%median 2.2%3.1%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. 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."

Other drugs in the opioid antagonist class

DrugName typeReportsLatest 12 monthsMarked serious
Suboxonebrand20,91955266.8%
Movantikbrand1,9974526.9%
Buprenorphine and naloxonegeneric1,9356653.7%
Naloxonegeneric1,69312994.2%
Relistorbrand9782855.4%
Zubsolvbrand9734421%
Narcanbrand8353856.2%
Buprenorphine hydrochloride, naloxone hydrochloridegeneric8247757.9%
Naloxone hydrochloridegeneric5376173.4%

Ordered by report count for navigation only. 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." A brand and its generic are separate rows because reporters name them separately.

Questions about Symproic reports

How many adverse event reports has FDA received for Symproic?

548 reports list Symproic as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 13 of them arrived in the latest 12 months. Another 855 list it only as a concomitant medication.

What reactions are recorded in Symproic reports?

diarrhoea (20.3%), drug ineffective (14.6%), abdominal pain (10.4%), nausea (6.4%) and constipation (5.7%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Symproic was responsible.

How serious are the reports?

47.3% are marked serious by the reporter. Among the outcomes recorded, 25.5% of reports include death and 15.1% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

consumer or non-health professional (49.5%), physician (32.8%) and pharmacist (13.5%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Symproic rising?

13 reports in the 12 months to June 2026, down 57% from 30 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Symproic was responsible for these reactions?

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." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Symproic?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

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. A report counts here when it lists Symproic as a suspect or interacting product; reports listing it only as a concomitant medication (855) are excluded. 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.