Please note: a valid prescription is required for all prescription medication.
Verapamil SR is a sustained-release form of the calcium channel blocker verapamil used to treat high blood pressure and help prevent chronic angina. The extended-release design provides steady 24‑hour control with once‑daily dosing for many patients. With US delivery from Canada and access to Canadian pricing, cash‑pay patients, including those without insurance, often find therapy more affordable.
What Calan SR® Is and How It Works
Calan SR® is a brand of extended-release verapamil, a non‑dihydropyridine calcium channel blocker. It relaxes vascular smooth muscle and reduces the heart’s workload by slowing conduction through the AV node. The result is lower blood pressure, fewer angina episodes, and controlled heart rate in certain rhythm conditions when prescribed. At CanadianInsulin, orders are filled by licensed Canadian pharmacies after we confirm a valid prescription with your clinic.
Extended-release verapamil releases medication gradually over the day. This helps maintain even blood levels and may reduce peaks that can cause dizziness or flushing. It is not intended for sudden chest pain or hypertensive emergencies.
Who Calan SR Is For
Approved uses include treatment of hypertension and prevention of chronic stable angina. Clinicians may also use extended-release verapamil to help control ventricular rate in selected supraventricular arrhythmias where long‑acting therapy is appropriate.
It is not suitable for everyone. Patients with severe left ventricular dysfunction, cardiogenic shock, second‑ or third‑degree AV block or sick sinus syndrome without a pacemaker, or severe hypotension should generally avoid verapamil. Use caution in heart failure, hepatic impairment, and when combined with other medicines that slow heart rate. For broader context on cardiovascular therapy, explore our categories Hypertension Cardiovascular and Heart Disease.
Dosage and Usage
Verapamil SR is typically taken once daily at the same time each day. Follow the directions on the pharmacy label for the specific brand dispensed, as some extended‑release tablets are taken with food and others without.
Tablets should be swallowed whole. Do not crush or chew extended‑release tablets. If a tablet is scored and the product information or pharmacist indicates it may be split, follow those instructions carefully. Dose adjustments are often made gradually based on blood pressure, heart rate, and tolerability.
This medicine is not for rapid relief of chest pain. Use of rescue medication for acute angina should continue as directed by a clinician.
Strengths and Forms
Commonly available forms include extended‑release (SR) tablets in several strengths used for once‑daily or twice‑daily regimens. Immediate‑release tablets and extended‑release capsules exist in some markets, but availability varies by manufacturer and pharmacy. Specific strengths stocked can differ; our team will dispense the strength specified on a valid prescription when available.
Missed Dose and Timing
If a dose is missed, take it when remembered unless the next dose is approaching. In that case, skip the missed dose and resume the regular schedule. Do not double doses. Keeping a daily reminder or using a pill organizer helps maintain a consistent routine.
Storage and Travel Basics
Store tablets at room temperature, protected from moisture and excessive heat. Keep in a tightly closed, child‑resistant container and out of reach of children and pets. When traveling, keep medication in original labeled packaging in a carry‑on bag to maintain access and avoid temperature extremes. Temperature‑sensitive items ship with cold‑chain handling and insulated packaging.
Benefits
Potential benefits, when used as directed, include:
- Steady, 24‑hour blood pressure control with convenient once‑daily dosing
- Reduced frequency and severity of chronic stable angina episodes
- Improved exercise tolerance in some patients with angina
- Rate control in selected supraventricular arrhythmias when long‑acting therapy is suitable
- Possible reduction in cardiovascular risk when blood pressure is consistently controlled as part of a comprehensive care plan
Side Effects and Safety
Common, usually mild effects may include:
- Constipation
- Dizziness or lightheadedness
- Headache
- Fatigue
- Edema of the ankles or feet
- Flushing or warmth
- Nausea
Less common but important risks can include slow heart rate, low blood pressure, atrioventricular block, worsening heart failure in susceptible patients, liver enzyme elevations, and rare allergic reactions. Gum overgrowth (gingival hyperplasia) can occur with chronic use; good dental hygiene and routine dental visits are helpful.
Seek urgent care for symptoms suggestive of severe bradycardia, fainting, severe shortness of breath, chest pain not relieved by rescue medication, or signs of severe allergic reaction.
Drug Interactions and Cautions
Verapamil is metabolized primarily by CYP3A4 and can interact with medicines or foods that inhibit or induce this pathway. Notable interactions include:
- Grapefruit products, which may raise verapamil levels
- Strong CYP3A4 inhibitors or inducers (for example, certain antifungals, macrolide antibiotics, HIV therapies, rifamycins, or St John’s wort)
- Beta blockers and other heart‑rate–lowering drugs, which can increase the risk of bradycardia or AV block
- Digoxin, with potential increases in digoxin levels
- Some statins; dose limits may apply to reduce myopathy risk
- Carbamazepine, lithium, or other agents where levels or effects can change with verapamil
When reading about related therapies, see Acebutolol Uses for beta‑blocker background and Lipitor Uses for statin therapy context. Alcohol may intensify dizziness and can affect certain controlled‑release formulations; moderation and consistency are prudent.
What to Expect Over Time
Blood pressure often improves progressively with regular dosing. Angina frequency may decline as steady coronary blood flow and reduced cardiac workload are maintained. Constipation, if present, may be persistent but often responds to diet, hydration, and activity adjustments. Many patients require ongoing therapy, with periodic monitoring of blood pressure, heart rate, and, when indicated, ECG and labs to guide dose adjustments.
Compare With Alternatives
Other long‑acting calcium channel blockers and beta blockers may be considered based on clinical profile, concurrent conditions, and response. Diltiazem offers a similar class alternative with a different balance of heart‑rate and vessel effects; see Diltiazem HCL CD. A dihydropyridine option that focuses on vascular relaxation is Nifedipine. Beta blockers may be preferred in some angina or post‑MI settings, guided by individual history and tolerability.
Pricing and Access
Canadian pharmacy pricing can offer meaningful savings compared with typical US cash‑pay. Start an order for Verapamil SR and our team will coordinate dispensing through licensed Canadian pharmacies. Enjoy prompt, express, cold‑chain shipping, with US delivery from Canada. For category browsing, see Heart Health Medications. Interested in periodic savings? Visit our Promotions page for current offers.
Availability and Substitutions
Availability can vary by strength and manufacturer. If a specific brand or strength is not available, a prescriber may recommend a therapeutically suitable alternative or an equivalent generic. When therapy goals suggest a different class, options like Metoprolol may be considered based on clinical factors.
Patient Suitability and Cost‑Saving Tips
Good candidates for extended‑release verapamil generally include adults with hypertension or chronic stable angina who would benefit from once‑daily dosing and heart‑rate–modulating effects. It may be less suitable in significant conduction abnormalities, certain heart failure states, or where drug interactions pose added risk.
- Ask a clinician if multi‑month supplies are appropriate to reduce refill frequency
- Using a single pharmacy can help coordination and interaction checks
- Set secure refill reminders to avoid missed doses
- For travel, keep medication in carry‑on bags with the original label for security checks
Questions to Ask Your Clinician
- Is extended‑release verapamil appropriate for the specific hypertension or angina profile?
- What monitoring is recommended for heart rate, blood pressure, and potential conduction effects?
- Which medicines, supplements, or grapefruit products should be avoided or adjusted?
- Would a beta blocker or a dihydropyridine calcium channel blocker be a better fit?
- What signs of low heart rate or low blood pressure require evaluation?
- How should constipation or swelling be managed if they occur?
Authoritative Sources
Ready to proceed? Start your Verapamil SR order with CanadianInsulin and benefit from prompt, express, cold‑chain shipping and US delivery from Canada.
Disclaimer: This information is educational and not a substitute for professional medical advice, diagnosis, or treatment. Always follow the directions provided by a prescribing clinician and the dispensing pharmacy label.
Express Shipping - from $25.00
Shipping with this method takes 3-5 days
Prices:
- Dry-Packed Products $25.00
- Cold-Packed Products $35.00
Standard Shipping - $15.00
Shipping with this method takes 5-10 days
Prices:
- Dry-Packed Products $15.00
- Not available for Cold-Packed products
- What is the difference between Verapamil SR and immediate‑release?- Verapamil SR is an extended‑release formulation designed to deliver verapamil gradually over many hours, often allowing once‑daily dosing and steadier blood levels. Immediate‑release tablets act more quickly and are typically dosed multiple times per day. Extended‑release products are not intended for acute symptoms such as sudden chest pain. 
- Can extended‑release verapamil tablets be split or crushed?- Extended‑release tablets should generally be swallowed whole and not crushed or chewed. Some SR tablets are scored and may be split if the specific product labeling allows. Follow the directions on the pharmacy label and consult a pharmacist if the tablet appears scored but instructions are unclear. 
- Does verapamil interact with grapefruit, alcohol, or other medicines?- Grapefruit products can raise verapamil levels and are best avoided. Alcohol may intensify dizziness and can affect certain controlled‑release designs. Important interactions include beta blockers, digoxin, some statins, strong CYP3A4 inhibitors or inducers, and drugs like carbamazepine or lithium. Provide a full medication list to the care team for review. 
- How long before blood pressure improves with extended‑release verapamil?- Response is individualized. Many patients see progressive blood pressure improvements with consistent daily use, but the timeline can vary based on dose, other medications, and overall health. Regular monitoring helps clinicians decide on dose adjustments. 
- Is verapamil safe for people with heart failure or conduction problems?- Caution is needed. Verapamil can worsen certain heart failure states and may cause or aggravate AV block or bradycardia, especially in patients with conduction disease. It is often avoided in second‑ or third‑degree AV block or sick sinus syndrome without a pacemaker. Clinicians weigh risks and benefits individually. 
- Can Verapamil SR be used during pregnancy or breastfeeding?- Use during pregnancy or breastfeeding requires individualized risk‑benefit assessment. Verapamil has been used when benefits are judged to outweigh risks, but decisions depend on the condition being treated and alternative options. Discuss timing, dosing, and monitoring with the maternity care team. 
- What should be done if a dose of Verapamil SR is missed?- If a dose is missed, take it when remembered unless the next dose is near. Skip the missed dose if close to the next scheduled dose and resume the regular schedule. Do not double doses. Keeping a daily reminder can help prevent missed doses. 
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