Calan SR (Verapamil ER) Medication

We don't sell this brand-version medication.

Generic Alternative - Calan SR (Verapamil ER)

Prescription Prescription Required
Buy Verapamil ER
Dosage Quantity Buy Now
120mg Add To Cart
180mg Add To Cart
240mg Add To Cart
5 Star Excellence award from Shopper Approved for collecting at least 100 5 star reviews


Table of contents:

Drug Description


Calan SR is a prescription medication indicated to treat hypertension (high blood pressure). Reducing blood pressure lowers the risk of fatal and nonfatal cardiovascular events, especially strokes and myocardial infarctions. 

Belonging to the class of calcium channel blockers, Calan SR functions by inducing relaxation of blood vessels, thereby facilitating ease of blood flow. 

Uses and Dosage 

Before taking Calan SR and with each prescription refill, thoroughly review its medication guide and patient information leaflet. Consult your doctor or pharmacist if you have any questions or concerns. 

The dosage of Calan SR may vary per individual based on their medical condition and response to the treatment.  

Typically, Calan SR is taken once daily in the morning or every 12 hours as prescribed by the doctor, regardless of food intake. The tablets should be swallowed whole, not cut, crushed, or chewed, to avoid releasing the drug all at once, which may elevate the likelihood of adverse effects. 

For optimal results, regularly take Calan SR around the same time(s) each day and strictly adhere to the prescribed dosage and frequency as directed by your physician. 

Keep taking Calan SR even if you feel well, as high blood pressure usually does not manifest symptoms. Abruptly discontinuing this medication without consulting your physician may exacerbate certain conditions. Your dosage may need to be gradually decreased under medical supervision. 

Report to your doctor if your condition does not improve or deteriorate, such as persistent high blood pressure readings or increased blood pressure. 

Side Effects 

Listed below are the side effects associated with the use of Calan SR. If there are any prolonged or exacerbated symptoms, promptly inform your physician. 

Common Side Effects 

  • Constipation 
  • Headache 
  • Dizziness 
  • Abnormal liver function tests 

Serious Side Effects 

  • Chest pain 
  • Fast or slow heart rate 
  • Feeling light-headed or faint 
  • Shortness of breath, even with mild exertion 
  • Swelling and rapid weight gain 
  • Signs of lung problems: 
    • Anxiety 
    • Sweating 
    • Pale skin 
    • Wheezing 
    • Gasping for breath 
    • Cough with foamy mucus 
  • Signs of liver problems: 
    • Loss of appetite 
    • Upper stomach pain 
    • Tiredness 
    • Easy bruising or bleeding 
    • Dark urine 
    • Clay-colored stools 
    • Jaundice (yellowing of the skin or eyes) 

Call your doctor and ask for medical help if you experience any of the above-listed severe symptoms. 

Allergic Reactions 

In rare cases, Calan SR may cause a severe allergic reaction. Seek emergency medical care if you experience any of the following symptoms of a severe allergic reaction: 

  • Rash 
  • Face, tongue, or throat itching or swelling 
  • Severe dizziness 
  • Trouble breathing 

This list does not contain all the potential side effects of Calan SR. If you experience other effects not listed above, inform your doctor promptly. 


Before starting treatment with Calan SR, inform your doctor and pharmacist if you have any known hypersensitivities, especially to verapamil, other medicines, or any ingredients present in Calan SR tablets. 

To ensure Calan SR is safe for you, disclose to your physician your medical background, specifically regarding any history of: 

  • Certain types of heart rhythm disorders (e.g., second- or third-degree atrioventricular block, sick sinus syndrome without a pacemaker, Wolff-Parkinson-White syndrome, Lown-Ganong-Levine syndrome) 
  • Heart failure 
  • Certain muscle or nerve conditions (e.g., muscular dystrophy, myasthenia gravis) 
  • Liver disease 
  • Kidney disease 

Before taking Calan SR, inform your doctor and pharmacist about all your medications, including prescription and over-the-counter drugs, dietary supplements, and herbal products, to prevent drug interactions. 

Some products that may interact with Calan SR include: 

  • Aliskiren 
  • Clonidine 
  • Disopyramide 
  • Dofetilide 
  • Dolasetron 
  • Fingolimod 
  • Lithium 

Calan SR removal from the body can be impacted by other medications, potentially affecting its efficacy. Examples of such medications include: 

  • Erythromycin 
  • Rifamycins (such as rifampin) 
  • Ritonavir 
  • St. John’s wort  
  • Others 

Calan SR may decrease the removal of other medications from the body, affecting their efficacy. Medicines that may be impacted include: 

  • Asunaprevir 
  • Colchicine 
  • Flibanserin 
  • Ivabradine 
  • Lomitapide 
  • Midazolam 
  • Triazolam 
  • Others 

Be sure to tell your doctor and pharmacist if you are taking cough-and-cold products, diet aids, or NSAIDs such as ibuprofen/naproxen, as certain ingredients in these products may cause an increase in heart rate or blood pressure. Ask them about the safe usage of these products. 

Consult your doctor regarding the consumption of grapefruit products, as they may interact with Calan SR and cause hazardous effects. 

Calan SR may cause drowsiness, dizziness, or lightheadedness, affecting your ability to think and react. Exercise caution while driving or operating machinery and avoid sudden changes in posture to prevent falls. 

Discuss the risks and benefits of Calan SR with your doctor if you are pregnant or plan to become pregnant, as it is unknown whether the medication will harm an unborn baby. 

Nursing mothers should discontinue breastfeeding while taking Calan SR due to the possibility of adverse reactions in infants from the drug, as verapamil is excreted in human milk. 

Additional information

Generic name:

Verapamil ER


24hour ER Capsule


120mg, 180mg, 240mg

Quantities Available:

60, 90

Quality Prescription Drugs has provided information from third parties intended to increase awareness and does not contain all the information about Calan SR (Verapamil ER). Talk to your doctor or a qualified medical practitioner for medical attention, advice, or if you have any concerns about Calan SR (Verapamil ER).