What is Calan Sr: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Calan Sr overview

BRAND NAMES:

  • Calan, Calan SR, Verelan, Verelan PM, Verelan PM, Verelan PM

Generic Names:

  • Verapamil Hcl Er

Uses:

  • Treats high blood pressure, severe angina, and arrhythmia. This medicine is a calcium channel blocker.

Therapeutic Classes:

  • Antianginal, Antiarrhythmic, Group IV, Antihypertensive, Antimigraine, Cardiovascular Agent

Forms:

  • Long Acting Capsule, Tablet, Long Acting Tablet

How it’s taken:

  • By mouth

What is Calan Sr used for?

What form(s) does Calan Sr come in

  • Long Acting Capsule

  • Tablet

  • Long Acting Tablet

What are common Calan Sr doses?

  • Tablet 120mg

  • Tablet 180mg

  • Tablet 240mg

Common Calan Sr prescriptions

  • Calan SR
    120mg tablet

  • Calan SR
    180mg tablet

  • Calan SR
    240mg tablet

  • Calan SR
    120mg tablet extended release

  • Calan SR
    180mg tablet extended release

  • Calan SR
    240mg tablet extended release

How to take Calan Sr

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

  • Oral routeIt is best to take this medicine with food or milk.

  • Swallow the extended-release tablet or extended-release capsule whole. Do not crush, break, or chew it.

  • If you take the Verelan® or Verelan® PM extended-release capsule, you may open it and pour the medicine into a small amount of applesauce. Stir this mixture well and swallow it without chewing.

  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • Swallow the extended-release tablet or extended-release capsule whole. Do not crush, break, or chew it.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

  • If you take the Verelan® or Verelan® PM extended-release capsule, you may open it and pour the medicine into a small amount of applesauce. Stir this mixture well and swallow it without chewing.

  • Oral routeIt is best to take this medicine with food or milk.

  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

What to do if you miss a dose of Calan Sr

Calan Sr contraindications

  • This medicine is not right for everyone. Do not use it if you had an allergic reaction to verapamil.

Calan Sr warnings

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, nerve disease, or muscle disease. Tell your doctor about all heart problems that you have.

  • This medicine may cause the following problems:Heart failureLow blood pressureLiver problemsChanges in heart rhythm

  • This medicine may make you dizzy or lightheaded. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

  • Tell any doctor or dentist who treats you that you use this medicine.

  • Your blood pressure may go up if you stop using this medicine. High blood pressure usually has no symptoms. Even if you feel well, do not stop using this medicine without asking your doctor.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Unusual tiredness or weakness

Calan Sr interactions

  • Some medicines can affect how verapamil works. Tell your doctor if you are using any of the following: Aspirin, carbamazepine, cimetidine, clonidine, cyclosporine, digitalis, digoxin, erythromycin, everolimus, ivabradine, lithium, phenobarbital, rifampin, ritonavir, sirolimus, telithromycin, temsirolimus, theophylline, vecuroniumBlood pressure medicine (including atenolol, metoprolol, prazosin, timolol)Cancer medicines (including cisplatin, cyclophosphamide, doxorubicin, paclitaxel, prednisone, procarbazine, vindesine)Diuretic (water pill)Medicine for heart rhythm problem (including disopyramide, flecainide, quinidine)Statin medicine

  • Do not drink alcohol while you are using this medicine.

  • Do not eat grapefruit or drink grapefruit juice while you are using this medicine.

  • Tell any doctor or dentist who treats you that you use this medicine.

  • Your blood pressure may go up if you stop this medicine. High blood pressure usually has no symptoms. Even if you feel well, do not stop using this medicine without asking your doctor.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Calan Sr side effects

Serious Side Effects

  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes

  • Rapid weight gain, swelling in your legs, feet, or ankles

  • Unusual tiredness or weakness

  • Chest pain, trouble breathing

  • Lightheadedness, dizziness, fainting

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

  • Fast, slow, uneven, or pounding heartbeat

  • Unusual tiredness or weakness

Less Serious Side Effects

  • Constipation