Reported Reactions

Drugs

Product name as reported

Isoptin: adverse event reports filed with FDA

776 reports list it as a suspect or interacting product, 2004–2026. Also reported as Isoptin /00014302/, Isoptin /00014301/.

776
reports as suspect product
0% of all reports · about 34 a year
8
reports, 12 months to June 2026
23 in the 12 months before
97.2%
marked serious by the reporter
57.4% across all reports
11.6%
record death among outcomes, as reported
90 reports · not verified by FDA

Between January 2004 and June 2026, 776 adverse event reports received by FDA list the product name "Isoptin" as reporters wrote it as a suspect or interacting product. Reports that mention it only as a concomitant medication (1,865) are left out of every figure here.

In the 12 months to June 2026, 8 reports listed it, down 65% from 23 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 34 reports a year and 0% of the 20,646,523 reports in the database. How many people take it is not in the data, so a count is not a rate of occurrence.

Reporters most often recorded drug interaction (14.6%), hypotension (11.3%) and bradycardia (10.7%). A report can list several reactions, so shares add to more than 100%; 326 different terms appear across these reports. Drug interaction is recorded in 14.6% of these reports, against 0.8% of all reports in the database.

97.2% of the reports are marked serious by the reporter; 11.6% record death among the outcomes and 70.1% record hospitalisation, as reported. 37.2% of the reports came from other health professionals, and the largest patient age group is 75 and over (31.4%). 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

047Jul 2021: 2Aug 2021: 0Sep 2021: 3Oct 2021: 2Nov 2021: 3Dec 2021: 22022Jan 2022: 3Feb 2022: 7Mar 2022: 2Apr 2022: 5May 2022: 2Jun 2022: 2Jul 2022: 0Aug 2022: 0Sep 2022: 5Oct 2022: 2Nov 2022: 0Dec 2022: 12023Jan 2023: 0Feb 2023: 5Mar 2023: 0Apr 2023: 4May 2023: 1Jun 2023: 1Jul 2023: 1Aug 2023: 0Sep 2023: 3Oct 2023: 1Nov 2023: 3Dec 2023: 02024Jan 2024: 1Feb 2024: 0Mar 2024: 2Apr 2024: 0May 2024: 2Jun 2024: 0Jul 2024: 1Aug 2024: 1Sep 2024: 4Oct 2024: 2Nov 2024: 4Dec 2024: 32025Jan 2025: 2Feb 2025: 0Mar 2025: 0Apr 2025: 0May 2025: 2Jun 2025: 4Jul 2025: 1Aug 2025: 1Sep 2025: 0Oct 2025: 1Nov 2025: 0Dec 2025: 02026Jan 2026: 0Feb 2026: 0Mar 2026: 0Apr 2026: 0May 2026: 2Jun 2026: 3

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

042842004: 8420042005: 542006: 262007: 5220072008: 452009: 282010: 3520102011: 372012: 282013: 1620132014: 382015: 362016: 2420162017: 292018: 432019: 4820192020: 492021: 202022: 2920222023: 192024: 202025: 1120252026: 5

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Isoptin reports recording the termall reports in the database

  1. Drug interactionan interaction between medicines14.6%113
  2. Hypotensionlow blood pressure11.3%88
  3. Bradycardiaslow heart rate10.7%83
  4. Nauseafeeling sick7.6%59
  5. Dyspnoeashortness of breath7.1%55
  6. Malaisegeneral feeling of being unwell5.9%46
  7. Atrial fibrillationan irregular heart rhythm4.3%33
  8. Hyperkalaemiahigh blood potassium4.3%33
  9. Overdosea dose above the recommended amount4%31
  10. Pruritusitching3.7%29
  11. Pyrexiafever3.7%29
  12. Suicide attempta suicide attempt3.7%29
  13. Dizzinesslight-headedness or unsteadiness3.6%28
  14. Vomitingbeing sick3.6%28
  15. Loss of consciousnesspassing out3.4%26
  16. Renal failurekidney failure3.4%26
  17. Drug ineffectivethe medicine did not work as expected3%23
  18. Cardiogenic shockshock from the heart failing to pump2.8%22
  19. Respiratory distressdifficulty breathing2.8%22
  20. Stevens-Johnson syndromea severe skin and mucous-membrane reaction2.8%22
  21. Astheniaweakness or lack of energy2.7%21
  22. Syncopefainting2.7%21
  23. Respiratory failurethe lungs could not supply enough oxygen2.6%20
  24. Toxic epidermal necrolysisa severe skin reaction with peeling2.6%20
  25. Headachehead pain2.4%19
  26. Areflexia2.3%18

Top 30 of 326 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 share of all reports in the database; 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

Death11.6%90
Life-threatening13.1%102
Hospitalisation (initial or prolonged)70.1%544
Disability1.9%15
Congenital anomaly0.1%1
Other serious35.3%274
Not serious2.8%22

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 20,646,523 reports. 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 20.3%2
2 to 110.1%1
12 to 170.6%5
18 to 448.4%65
45 to 6418.8%146
65 to 7420.9%162
75 and over31.4%244
Age not given19.5%151

Patient sex

Female53.6%416
Male39.7%308
Not given6.7%52

Who reported

Physician30.4%236
Pharmacist5.2%40
Other health professional37.2%289
Lawyer0%0
Consumer or non-health professional16.4%127
Not given10.8%84

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 4.5% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Hypertension11114.3%
Atrial fibrillation587.5%
Arrhythmia172.2%
Essential hypertension172.2%
Cluster headache70.9%
Angina pectoris50.6%

The indication field is filled in by the reporter and is often blank; shares are of all 776 reports.

In context

MeasureIsoptinAll reports
Reports as suspect product77620,646,523
Share of that pool—0%
Reports, latest 12 months81,332,454
Marked serious97.2%57.4%
Death recorded among outcomes, per 1,000 reports11691
Hospitalisation recorded, per 1,000 reports701213
Consumer-filed share16.4%45.8%
Top term, share of reportsDrug interaction 14.6%0.8%

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."

Questions about Isoptin reports

How many adverse event reports has FDA received for Isoptin?

776 reports list Isoptin as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 8 of them arrived in the latest 12 months. Another 1,865 list it only as a concomitant medication.

What reactions are recorded in Isoptin reports?

drug interaction (14.6%), hypotension (11.3%), bradycardia (10.7%), nausea (7.6%) and dyspnoea (7.1%). 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 Isoptin was responsible.

How serious are the reports?

97.2% are marked serious by the reporter. Among the outcomes recorded, 11.6% of reports include death and 70.1% 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?

other health professional (37.2%), physician (30.4%) and consumer or non-health professional (16.4%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Isoptin rising?

8 reports in the 12 months to June 2026, down 65% from 23 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 Isoptin 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 Isoptin?

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 Isoptin as a suspect or interacting product; reports listing it only as a concomitant medication (1,865) 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.