Diltiazem XC® Extended-Release Capsules for Hypertension and Angina

Diltiazem XC is an extended-release calcium channel blocker in capsule form. It is used to lower blood pressure and help prevent episodes of angina. This page outlines how it works, who it may suit, and how to use it safely.

What Diltiazem XC Is and How It Works

Diltiazem XC® is a once-daily formulation of diltiazem, a non-dihydropyridine calcium channel blocker. It reduces calcium entry into cardiac and vascular smooth muscle cells, which can slow heart rate, reduce myocardial oxygen demand, and relax arteries. This combination helps lower blood pressure and decrease the frequency of stable angina. US shipping from Canada is available for eligible prescriptions through CanadianInsulin.

CanadianInsulin.com is a prescription referral platform. We verify prescriptions with your prescriber when required, and licensed Canadian pharmacies dispense your order. Pricing may be different than local cash pay rates without insurance, and selection can vary by pharmacy.

Diltiazem affects the AV node and peripheral vasculature. By improving coronary blood flow and lowering afterload, it can ease exertional chest discomfort. Diltiazem HCl ER capsules release medicine gradually over 24 hours to maintain steadier blood levels.

Who It’s For

This medicine is indicated for adults with hypertension and for the prophylaxis of chronic stable angina or vasospastic (Prinzmetal) angina. For more on conditions it treats, see our guides to Hypertension and Angina. Use for arrhythmia control varies by formulation and clinical setting; follow the product’s official label.

Do not use if you have hypersensitivity to diltiazem, severe hypotension, sick sinus syndrome or second/third-degree AV block without a functioning pacemaker, acute myocardial infarction with pulmonary congestion, or cardiogenic shock. People with heart failure, significant bradycardia, hepatic impairment, or renal impairment require careful supervision. To learn about rhythm disorders more broadly, visit Atrial Fibrillation. Diltiazem extended-release capsules are swallowed whole and are not intended for rapid conversion of arrhythmias.

Dosage and Usage

Follow the specific product label and your prescriber’s instructions. Initiation and titration schedules differ by brand and strength. Many adults start once daily, then adjust at intervals based on blood pressure or angina control and tolerability. Take at the same time each day for consistent effect.

Swallow capsules whole with water. Do not crush or chew. Some branded ER products have unique instructions about food; check your patient leaflet. Diltiazem XC capsules are designed for controlled release and should be taken as directed. If you monitor blood pressure at home, log readings and share them at follow-up visits. See our category overview for heart medicines under Cardiovascular.

Strengths and Forms

This treatment is supplied as extended-release oral capsules. Availability can vary by supplier and jurisdiction.

• Common strengths: Diltiazem XC 120 mg, 180 mg, 240 mg, 300 mg
• Solid oral dosage form designed for once-daily use
• Color and imprint may differ by manufacturer

Missed Dose and Timing

If you miss a dose, take it when remembered the same day. If it is close to the next scheduled dose, skip the missed dose. Do not double up. Keep a consistent daily routine to maintain steady exposure.

Taking it in the morning may help with adherence, but timing can be individualized based on tolerability and guidance in the official label. Avoid sudden discontinuation without medical advice, particularly if using it for angina prophylaxis.

Storage and Travel Basics

Store capsules at room temperature in the original container. Keep them away from moisture and excessive heat. Protect from light where advised in the package insert. Always keep out of reach of children and pets.

When you travel, bring your medicine in carry-on luggage with the original labeled container. Pack a simple dosing schedule and set reminders on your phone. Carry a copy of your prescription or a pharmacy receipt to avoid delays during security checks. If your itinerary crosses time zones, plan dosing with your clinician in advance.

Benefits

Calcium channel blockade can reduce vascular resistance and improve oxygen balance in the heart muscle. Once-daily capsules may support better adherence versus multiple daily doses. More stable 24‑hour exposure can help smooth blood pressure variability and angina prevention.

By reducing heart rate and contractility in a controlled way, this medicine can temper exertional symptoms. When used as part of a broader plan that includes diet and activity, it may help you reach blood pressure targets set by your clinician. For practical guidance, see our article Best Practices 2025.

Side Effects and Safety

• Headache or dizziness: often mild and transient
• Peripheral edema: ankle or foot swelling may occur
• Flushing or warmth: usually brief
• Fatigue or weakness: monitor when starting therapy
• Nausea or constipation: take with water and regular meals

Less common but serious effects can include worsening heart failure, clinically significant bradycardia, AV block, hypotension, liver enzyme elevations, or skin reactions. Seek urgent care for fainting, severe shortness of breath, marked swelling, jaundice, or rash with mucosal involvement. If you use beta blockers or other rate-slowing agents, be alert for additive effects such as low heart rate or conduction disturbances.

Drug Interactions and Cautions

Diltiazem is a CYP3A4 substrate and moderate inhibitor. Potent CYP3A inhibitors or inducers can alter drug exposure. Avoid grapefruit or grapefruit juice, which can increase levels. Use caution with other negative chronotropes such as beta blockers, digoxin, or certain antiarrhythmics due to additive effects on the AV node.

Diltiazem can raise concentrations of sensitive CYP3A substrates such as simvastatin; dose limits or alternative statins may be considered per labeling. Monitor if combined with cyclosporine, tacrolimus, or carbamazepine. Alcohol can potentiate hypotension and dizziness. Always review all prescription, OTC, and herbal products with your clinician or pharmacist before starting this treatment.

What to Expect Over Time

Blood pressure may improve gradually with consistent daily use. Angina frequency can decrease with an effective, tolerated dose alongside other prescribed cardiac medicines. It may take periodic adjustments to find a stable regimen.

Track readings, note symptoms such as dizziness or swelling, and follow up as scheduled. Lifestyle measures remain essential. For background on blood pressure goals and adjunctive therapy, explore Diabetes and Hypertension and our primer Atenolol and Hypertension.

Compare With Alternatives

Other calcium channel blockers may be considered if you need a different option. Non-dihydropyridines like Verapamil can provide similar rate-slowing effects but have distinct profiles and dosing. A dihydropyridine option such as Norvasc (amlodipine) acts primarily on vascular smooth muscle and is commonly used for hypertension and angina.

Choice depends on comorbidities, tolerability, and concomitant medications. Discuss options and monitoring with your prescriber to align therapy with your goals. For a broader overview of related therapies, see our category on Cardiovascular medicines.

Pricing and Access

We list Diltiazem XC price transparently on the product page. Selection can vary by strength. You can compare options and place an order after prescription verification. For deals and seasonal offers, visit our Promotions page. We provide encrypted checkout for secure payment.

Orders are fulfilled by licensed Canadian pharmacies, with US delivery from Canada for eligible prescriptions. If budget is a concern, ask your prescriber about generics or therapeutic alternatives. For additional context on BP treatments and access, see How Bystolic Helps and How Altace Supports.

Availability and Substitutions

Supply can vary by strength and manufacturer. If a specific capsule is unavailable, your prescriber may recommend a therapeutically appropriate alternative or another extended-release formulation. For example, some patients may be switched to Diltiazem HCl CD, depending on clinical judgment and local availability.

Patient Suitability and Cost-Saving Tips

This therapy may suit adults needing once-daily blood pressure control or angina prophylaxis without contraindications. It may not suit people with significant conduction disease, decompensated heart failure, or severe hypotension. Review your full medical history and all medicines with your clinician before starting.

To reduce overall costs, consider multi-month fills if approved, align refills with routine checkups, and set reminders to avoid urgent local purchases. If you manage multiple heart conditions, browsing our sections on Hypertension and Angina can help you compare options. For education across conditions, see Atrial Fibrillation resources as well.

Questions to Ask Your Clinician

• Starting dose plan: how it will be adjusted
• Food considerations: whether to take with meals
• Drug interactions: statins, beta blockers, digoxin
• Side effects: when to call for help
• Monitoring: home BP goals and office follow-up
• Angina plan: use with nitrates or other therapies

Authoritative Sources

For full US labeling and patient information, see FDA DailyMed for diltiazem extended-release capsules: review the DailyMed index for current monographs.

For Canadian product and ingredient records, consult Health Canada’s Drug Product Database: search the DPD for diltiazem entries.

For mechanism and class background, the FDA provides labeling archives for calcium channel blockers: browse the FDA Drug Approval database.

You can buy Diltiazem XC online after your prescription is verified. Choose secure checkout with prompt, express shipping with temperature-controlled handling when required. Medical disclaimer: This content is for informational purposes only and is not a substitute for professional medical advice.