Two medicines, side by side
Diltiazem vs telmisartan
Diltiazem and telmisartan are both labeled for high blood pressure. Drugs@FDA records approvals of diltiazem since 1982 and of telmisartan since 1998. Pharmacies paid $0.144 per diltiazem 24h ER(cd) 120 mg capsule and $0.106 per telmisartan 20 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. In FDA's classes, diltiazem is a calcium channel blocker and telmisartan an angiotensin 2 receptor blocker.
Check it at the source: the diltiazem FDA label on DailyMed (effective August 7, 2026); the telmisartan FDA label on DailyMed (effective May 29, 2026).
Highlights of the diltiazem record
Diltiazem (Cardizem) · label of August 7, 2026
Used for
From the label: indicationsHypertension Tiazac is indicated for the treatment of hypertension. It may be used alone or in combination with other antihypertensive medications. Chronic Stable Angina Tiazac is indicated for the treatment of chronic stable angina.
On the market
- Earliest approval on file
- November 5, 1982
- Generic labelers
- 50 labelers
- Pharmacy cost
- $0.144 per capsule
Supply and safety
- Shortage
- A presentation being discontinued
- Recalls
- 29
Highlights of the telmisartan record
Telmisartan (Micardis) · label of May 29, 2026
FETAL TOXICITY When pregnancy is detected, discontinue telmisartan as soon as possible [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1)]. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1)]. WARNING: FETAL TOXICITY See full prescribing information for complete boxed warnings.
Used for
From the label: indicationsTelmisartanis an angiotensin II receptor blocker (ARB) indicated for: Treatment of hypertension to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions(1.1) 1.1 Hypertension Telmisartan is indicated for the treatment of hypertension, to lower blood pressure. […]
On the market
- Earliest approval on file
- November 10, 1998
- Generic labelers
- 28 labelers
- Pharmacy cost
- $0.106 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 3
Source: FDA drug labels via openFDA (Diltiazem label of August 7, 2026, Telmisartan label of May 29, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do diltiazem and telmisartan differ on the record?
In FDA's classes, diltiazem is a calcium channel blocker and telmisartan an angiotensin 2 receptor blocker.
How each works, in its label's words: Diltiazem, “Mechanisms of Action Hypertension: Diltiazem produces its antihypertensive effect primarily by relaxation of vascular smooth muscle and the resultant decrease in peripheral vascular resistance.”; Telmisartan, “Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II).”
Half-life, in each label's words: Diltiazem, “The plasma elimination half-life of diltiazem is approximately 3.0 to 4.5 hours.”; Telmisartan, “Telmisartan shows bi-exponential decay kinetics with a terminal elimination half-life of approximately 24 hours.”
Only the telmisartan label carries a boxed warning.
Generics: diltiazem since 1992; telmisartan since 2014 (Drugs@FDA).
| Diltiazem | Telmisartan | |
|---|---|---|
| Labeled for | High blood pressure, Angina, Atrial fibrillation | High blood pressure, Heart attack and coronary artery disease |
| Pharmacologic class | Calcium Channel Blocker | Angiotensin 2 Receptor Blocker |
| How it works (label) | Mechanisms of Action Hypertension: Diltiazem produces its antihypertensive effect primarily by relaxation of vascular smooth muscle and the resultant decrease in peripheral vascular resistance. | Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). |
| Half-life (label) | The plasma elimination half-life of diltiazem is approximately 3.0 to 4.5 hours. | Telmisartan shows bi-exponential decay kinetics with a terminal elimination half-life of approximately 24 hours. |
| Earliest approval on file (Drugs@FDA) | November 5, 1982 | November 10, 1998 |
| First generic approved | November 5, 1992 | January 8, 2014 |
| Generic labelers (NDC) | 50 labelers | 28 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.144 per capsule (Diltiazem 24h ER(cd) 120 mg capsule) | $0.106 per tablet (Telmisartan 20 mg tablet) |
| 12-month price change | -4% | -4% |
| Boxed warning | No | Yes |
| Shortage now | A presentation being discontinued | No current entry |
| Recalls recorded | 29 | 3 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 34,213 | 17,745 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
What next?
- Alternatives to diltiazem
- every medicine labeled for the same conditions