Drugs › Calcium channel blocker
Brand name · Diltiazem hydrochloride
Cardizem: adverse event reports filed with FDA
1,082 reports list it as a suspect or interacting product, 2004–2026. Class: Calcium channel blocker. Also reported as Cardizem Sr, Cardizem /00489701/, Cardizem /00489702/.
- 1,082
- reports as suspect product
- 0% of all reports · about 48 a year
- 15
- reports, 12 months to June 2026
- 28 in the 12 months before
- 68.4%
- marked serious by the reporter
- 87.7% across the class
- 4.8%
- record death among outcomes, as reported
- 52 reports · not verified by FDA
1,082 adverse event reports received by FDA list the brand name Cardizem (diltiazem hydrochloride) as a suspect or interacting product, from January 2004 to June 2026. A further 10,835 reports list it only as a concomitant medication, and those are not counted in the figures on this page.
In the 12 months to June 2026, 15 reports listed it, down 46% from 28 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 48 reports a year and 0% of the 20,646,523 reports in the database, and 1.4% of the reports for the calcium channel blocker class. How many people take it is not in the data, so a count is not a rate of occurrence.
The MedDRA terms listed most often are atrial fibrillation (12.8%), drug hypersensitivity (11.3%) and drug ineffective (11.3%). A report can list several reactions, so shares add to more than 100%; 389 different terms appear across these reports. Atrial fibrillation is recorded in 12.8% of these reports, a larger share than in the median calcium channel blocker drug (1.4%).
68.4% of the reports are marked serious by the reporter (87.7% across the class); 4.8% record death among the outcomes and 37.7% record hospitalisation, as reported. 43.6% of the reports came from consumers, and the largest patient age group is 75 and over (23.6%). 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
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
2026 covers reports received through June 2026 only.
Reactions recorded in the reports
share of Cardizem reports recording the termmedian drug in calcium channel blocker
- Atrial fibrillationan irregular heart rhythm12.8%139
- Drug hypersensitivityan allergic-type reaction to a medicine11.3%122
- Drug ineffectivethe medicine did not work as expected11.3%122
- Dizzinesslight-headedness or unsteadiness9.8%106
- Malaisegeneral feeling of being unwell8.2%89
- Fatiguetiredness7.6%82
- Drug interactionan interaction between medicines7.5%81
- Hypotensionlow blood pressure6.7%72
- Diarrhoealoose or frequent stools6.5%70
- Weight decreasedweight loss6.5%70
- Blood pressure increaseda raised blood pressure reading6%65
- Hypersensitivityan allergic-type reaction5.6%61
- Nauseafeeling sick5.6%61
- Dyspnoeashortness of breath5.5%60
- Rashskin rash5.5%59
- Hypoaesthesianumbness5.2%56
- Chest painchest pain5.1%55
- Bradycardiaslow heart rate5%54
- Painpain, site not specified5%54
- Coughcough4.7%51
- Headachehead pain4.6%50
- Pain in extremitypain in an arm or leg4.5%49
- Arthralgiajoint pain4.3%47
- Paraesthesiatingling or pins and needles4.3%46
- Swellingswelling4.3%46
- Astheniaweakness or lack of energy4.1%44
- Heart rate increaseda fast heart rate reading4%43
- Infectionan infection, type not specified3.9%42
Top 30 of 389 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 6 drugs in the calcium channel blocker 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
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 76,049 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
Patient sex
Who reported
Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 74.6% of reports give the United States as the country of the event or reporter.
Reason for use recorded
| Indication as recorded (MedDRA) | Reports | Share |
|---|---|---|
| Hypertension | 98 | 9.1% |
| Atrial fibrillation | 71 | 6.6% |
| Angina pectoris | 26 | 2.4% |
| Arrhythmia | 7 | 0.6% |
| Blood pressure | 7 | 0.6% |
| Essential hypertension | 6 | 0.6% |
The indication field is filled in by the reporter and is often blank; shares are of all 1,082 reports.
In context
| Measure | Cardizem | Calcium channel blocker | All reports |
|---|---|---|---|
| Reports as suspect product | 1,082 | 76,049 | 20,646,523 |
| Share of that pool | — | 1.4% | 0% |
| Reports, latest 12 months | 15 | — | 1,332,454 |
| Marked serious | 68.4% | 87.7% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 48 | 187 | 91 |
| Hospitalisation recorded, per 1,000 reports | 377 | 391 | 213 |
| Consumer-filed share | 43.6% | 25.1% | 45.8% |
| Top term, share of reports | Atrial fibrillation 12.8% | median 1.4% | 0.5% |
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 calcium channel blocker class
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Amlodipine | generic | 52,216 | 4,324 | 93.2% |
| Norvasc | brand | 12,362 | 124 | 69% |
| Diltiazem hydrochloride | generic | 6,082 | 504 | 88.3% |
| Verapamil hydrochloride | generic | 2,547 | 156 | 87.5% |
| Caduet | brand | 1,760 | 3 | 66% |
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 Cardizem reports
How many adverse event reports has FDA received for Cardizem?
1,082 reports list Cardizem as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 15 of them arrived in the latest 12 months. Another 10,835 list it only as a concomitant medication.
What reactions are recorded in Cardizem reports?
atrial fibrillation (12.8%), drug hypersensitivity (11.3%), drug ineffective (11.3%), dizziness (9.8%) and malaise (8.2%). 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 Cardizem was responsible.
How serious are the reports?
68.4% are marked serious by the reporter. Among the outcomes recorded, 4.8% of reports include death and 37.7% 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 (43.6%), other health professional (22.6%) and physician (21.6%). Most reports reach FDA through the manufacturer, which must forward reports it receives.
Are reports for Cardizem rising?
15 reports in the 12 months to June 2026, down 46% from 28 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 Cardizem 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 Cardizem?
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 Cardizem as a suspect or interacting product; reports listing it only as a concomitant medication (10,835) 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.