Isoptin SR is a prescription medication that is used to treat high blood pressure and to lower your heart rate. Isoptin SR contains the calcium channel blocker medication verapamil. Verapamil works by relaxing the blood vessels in order to allow blood to flow more easily around the body.

Make sure to always read the patient information and instructions before using this medication. Always follow your doctor’s directions.

• Isoptin SR should be taken with food.
• If your doctor has directed you to take this medication once a day, then take it in the morning.
• Swallow verapamil tablets whole without chewing or crushing.
• It can take up to a week to feel the full benefit of Isoptin SR>

Tell your doctor and pharmacist:

• About your drug and other allergies.
• If you take any other prescription or over-the-counter medications.
• Your medical history particularly of heart failure, abnormal heartbeat, slow heartbeat, low blood pressure, Lown-Ganong-Levine syndrome, sick sinus syndrome, Wolff-Parkinson-White syndrome
• If you are pregnant or planning pregnancy.
• If you drink alcohol.

You should also know:

• Isoptin SR can interact with several medications causing serious side effects. Keep a track of all other prescription and over-the-counter medications that you take and share these with your doctor and pharmacist. Tell your doctor before taking any new medications.
• You should not breast-feed while taking this medication.
• All of your doctors should be aware that you take this medication.
• Older adults may be more sensitive to the side effects of Isoptin SR.

Common side effects of Isoptin SR include but are not limited to:

• Headaches.
• Dizziness.
• Constipation.

Get medical help if you have any of the following side effects of verapamil.

• New or worsening abnormal heartbeat.
• Slow heartbeat.
• Severe dizziness or passing out.
• Shortness of breath.
• Rapid weight gain.
• Swelling in your arms or legs.
• Signs of a liver problem including tiredness, lack of hunger, stomach pain, upset stomach, dark urine, light colored stools, jaundice or vomiting.
• Symptoms of an allergic reaction such as difficulty breathing, hives or swelling in your face, lips or throat.

What should I do if I miss a dose of verapamil?

If you miss a dose of Isoptin SR, you should take it as soon as you remember. However, if it is almost time for your next dose, then skip your missed dose.

What is the strength of Isoptin SR?

Both Isoptin SR and the generic alternative verapamil SR are available in a strength of 180mg. Only brand name Isoptin SR is available in a strength of 240mg.