CALAN SR vs CARDIZEM SR

Independent side-by-side comparison.

Rated against independent regulatory sources·Last updated August 17, 2026·How we rate

Possible drug interaction. CALAN SR and CARDIZEM SR are different prescription medicines. Combining or switching between them can cause interactions — talk to a pharmacist or prescriber before making changes. This page is not medical advice.

Attribute	CALAN SR	CARDIZEM SR
Rating	64/100	New
Pharmacy pays	~$5.71 /30	~$9.18 /30
Type	RX	RX
Active ingredient	VERAPAMIL HYDROCHLORIDE	DILTIAZEM HYDROCHLORIDE
Manufacturer	Pfizer	Biovail
Dosage forms	Tablet, extended release	Capsule, extended release
Drug class	Calcium Channel Blocker	Calcium Channel Blocker
Boxed warning	None	None
Half-life	about 2.8 to 7.4 hours after a single dose, rising to about 4.5 to 12 hours with repeated dosing	about 3 to 4.5 hours
Treats	Variant Angina Pectoris, Atrial Fibrillation, Atrial Flutter	Variant Angina Pectoris, Atrial Fibrillation, Atrial Flutter

calan sr cardizem sr

Rating

64/100

New

Pharmacy pays

~$5.71 /30

~$9.18 /30

Type

Active ingredient

VERAPAMIL HYDROCHLORIDE

DILTIAZEM HYDROCHLORIDE

Manufacturer

Pfizer

Biovail

Dosage forms

Tablet, extended release

Capsule, extended release

Drug class

Calcium Channel Blocker

Boxed warning

None

Half-life

about 2.8 to 7.4 hours after a single dose, rising to about 4.5 to 12 hours with repeated dosing

about 3 to 4.5 hours

Treats

Variant Angina Pectoris, Atrial Fibrillation, Atrial Flutter

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Frequently asked questions

Which is cheaper, Calan SR or Cardizem SR?

Calan SR costs pharmacies less to acquire — about $5.71 vs $9.18 for a 30-count supply, per the CMS NADAC survey. That gap is in the pharmacy's cost of goods, not necessarily in what you pay: your price is set afterwards by your insurer and the pharmacy.

What is the difference between Calan SR and Cardizem SR?

Calan SR contains Verapamil Hydrochloride, while Cardizem SR contains Diltiazem Hydrochloride — they have different active ingredients.

Ratings are based on FDA regulatory (recall-safety) data. This comparison is for general reference only — not medical advice. Always consult a licensed professional before choosing or switching a medication.