What the label lists and what reports show
Diltiazem side effects
Diltiazem's FDA label: “The following table presents the most common adverse reactions, whether or not drug-related, reported in placebo-controlled trials in patients receiving Tiazac up to 360 mg and up to 540 mg with rates in placebo patients shown for comparison.” FAERS holds 34,213 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is dyspnoea (3,296 reports).
- Generic listed
- A presentation discontinued
Check it at the source: the diltiazem FDA label on DailyMed (effective August 7, 2026, Bausch Health US, LLC); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsThe following table presents the most common adverse reactions, whether or not drug-related, reported in placebo-controlled trials in patients receiving Tiazac up to 360 mg and up to 540 mg with rates in placebo patients shown for comparison.
MOST COMMON ADVERSE EVENTS IN DOUBLE-BLIND PLACEBO-CONTROLLED ANGINA TRIALS Adverse events occurring in treated patients at 2% or more than placebo-treated patients.
| Adverse Events (COSTART Term) | n=50 # pts (%) | Up to 360 mg n=158 # pts (%) | 540 mg n=49 # pts (%) |
|---|---|---|---|
| headache | 1 (2) | 13 (8) | 4 (8) |
| edema, peripheral | 1 (2) | 3 (2) | 5 (10) |
| pain | 1 (2) | 10 (6) | 3 (6) |
| dizziness | 0 (0) | 5 (3) | 5 (10) |
| asthenia | 0 (0) | 1 (1) | 2 (4) |
| dyspepsia | 0 (0) | 2 (1) | 3 (6) |
| dyspnea | 0 (0) | 1 (1) | 3 (6) |
| bronchitis | 0 (0) | 1 (1) | 2 (4) |
| AV block | 0 (0) | 0 (0) | 2 (4) |
| infection | 0 (0) | 2 (1) | 1 (2) |
| flu syndrome | 0 (0) | 0 (0) | 1 (2) |
| cough increase | 0 (0) | 2 (1) | 1 (2) |
| extrasystoles | 0 (0) | 0 (0) | 1 (2) |
| gout | 0 (0) | 2 (1) | 1 (2) |
| myalgia | 0 (0) | 0 (0) | 1 (2) |
| impotence | 0 (0) | 0 (0) | 1 (2) |
| conjunctivitis | 0 (0) | 0 (0) | 1 (2) |
| rash | 0 (0) | 2 (1) | 1 (2) |
| abdominal enlargement | 0 (0) | 0 (0) | 1 (2) |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedSerious adverse reactions have been rare in studies with Tiazac, as well as with other diltiazem formulations. It should be recognized that patients with impaired ventricular function and cardiac conduction abnormalities have usually been excluded from these studies. A total of 256 hypertensives were treated for between 4 and 8 weeks; a total of 207 patients with chronic stable angina were treated for 3 weeks with doses of Tiazac ranging from 120 to 540 mg once daily. Two patients experienced first-degree AV block at the 540 mg dose. The following table presents the most common adverse reactions, whether or not drug-related, reported in placebo-controlled trials in patients receiving Tiazac up to 360 mg and up to 540 mg with rates in placebo patients shown for comparison. MOST COMMON ADVERSE EVENTS IN DOUBLE-BLIND PLACEBO-CONTROLLED HYPERTENSION TRIALS Adverse events occurring in treated patients at 2% or more than placebo-treated patients. …
Source: FDA drug label, Bausch Health US, LLC, effective August 7, 2026 (SPL set c567fe7e-887e-4291-a0d1-2dd3f25cbf25), via openFDA; the full label on DailyMed
What do FAERS reports show?
34,213 reports list diltiazem among the medicines taken, each a report of something that happened, not proof the medicine caused it; 5,131 are coded as a death and 14,554 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 20 reactions below, 10 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Diltiazem: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions