Diltiazem

Generic Name: Diltiazem

Brand Names: Cardizem, Tiazac, Cartia XT

Diltiazem is used to treat high blood pressure, chest pain, and certain heart rhythm disorders. It is available as Cardizem, Tiazac, Cartia XT and is commonly prescribed in the cardiovascular category.

CardiovascularCalcium Channel BlockersHypertensionArrhythmia

Drug Class

Non-Dihydropyridine Calcium Channel Blocker (Benzothiazepine)

Pregnancy

Category C — Animal studies have shown teratogenic effects (skeletal abnormalities, embryo lethality) at doses several times the maximum human dose. There are no adequate well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.

Available Forms

Immediate-release tablet (30 mg, 60 mg, 90 mg, 120 mg), Extended-release capsule, 12-hour (60 mg, 90 mg, 120 mg), Extended-release capsule, 24-hour (120 mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg), IV injection (5 mg/mL), IV powder for reconstitution (25 mg, 50 mg, 100 mg vials)

What It's Used For

Diltiazem is prescribed to treat:

• High blood pressure, chest pain, and certain heart rhythm disorders • Various related conditions in the cardiovascular category • Associated symptoms and complications

It is an important medication that helps manage these conditions effectively.

Dosage Quick Reference

These are general dosage guidelines. Your doctor will determine the appropriate dose for your specific situation.

Condition	Starting Dose	Maintenance Dose
Hypertension (extended-release)	180–240 mg once daily	240–360 mg once daily; max 540 mg/day
Chronic stable angina (immediate-release)	30 mg four times daily	180–360 mg/day in divided doses
Atrial fibrillation — rate control (oral)	120–180 mg extended-release once daily	Titrate to heart rate goal; max 360 mg/day
Atrial fibrillation — rate control (IV bolus)	0.25 mg/kg IV over 2 minutes	Repeat 0.35 mg/kg if needed; infusion 5–15 mg/hr
Paroxysmal supraventricular tachycardia (IV)	0.25 mg/kg IV over 2 minutes	May repeat 0.35 mg/kg in 15 minutes if needed

Side Effects

Common side effects may include:

• Nausea or stomach upset • Headache • Dizziness or lightheadedness • Fatigue or tiredness • Mild rash or itching

Serious side effects (seek immediate medical attention):

• Severe allergic reactions (rash, hives, swelling, difficulty breathing) • Unusual bleeding or bruising • Severe stomach pain • Signs of liver problems (yellowing of skin/eyes, dark urine) • Chest pain or irregular heartbeat • Severe dizziness or fainting • Signs of serious adverse effects

Drug Interactions

Diltiazem is a moderate inhibitor of CYP3A4 and P-glycoprotein and slows AV nodal conduction, leading to a number of clinically important interactions.

Beta-blockers (e.g., metoprolol, atenolol, carvedilol): Additive negative inotropy and AV nodal blockade can cause severe bradycardia, heart block, or heart failure. Combine cautiously, particularly in patients with reduced ejection fraction or pre-existing conduction disease.
Statins metabolized by CYP3A4 (simvastatin, lovastatin): Diltiazem markedly increases statin levels, raising rhabdomyolysis risk. Limit simvastatin to 10 mg/day with diltiazem; consider switching to pravastatin, rosuvastatin, or pitavastatin.
Digoxin: Diltiazem can raise digoxin levels by 20–50 percent through P-glycoprotein inhibition. Monitor digoxin levels and watch for nausea, visual changes, or arrhythmia.
Cyclosporine, tacrolimus, sirolimus: Diltiazem significantly increases calcineurin/mTOR inhibitor levels. Monitor trough concentrations closely and adjust immunosuppressant doses.
CYP3A4 inducers (rifampin, carbamazepine, phenytoin): May reduce diltiazem efficacy. Consider an alternative agent or monitor blood pressure and heart rate response carefully.
Grapefruit juice: Inhibits intestinal CYP3A4 and can raise diltiazem exposure. Counsel patients to avoid large quantities.

Additional Information

What is Diltiazem?

Diltiazem (generic name: Diltiazem) is a medication primarily used to treat high blood pressure, chest pain, and certain heart rhythm disorders. It is marketed under the brand name(s) Cardizem, Tiazac, Cartia XT and belongs to the Cardiovascular category of medications.

How Does Diltiazem Work?

Diltiazem works through several mechanisms to provide therapeutic benefits:

Acts on specific receptors or pathways in the body
Modulates biological processes related to the treated condition
Provides symptom relief and improves quality of life
Helps manage the underlying condition effectively
Works best when combined with appropriate lifestyle modifications

The medication is designed to target the specific pathways involved in high blood pressure, chest pain, and certain heart rhythm disorders, making it an effective treatment option.

Common Uses

Primary Indications

Diltiazem is commonly prescribed for:

High blood pressure, chest pain, and certain heart rhythm disorders: The main indication for this medication
Related Conditions: Associated symptoms and complications
Prevention: May help prevent progression of certain conditions
Symptom Management: Reduces discomfort and improves daily function

Additional Uses

In some cases, Diltiazem may also be prescribed for:

Off-label uses as determined by your healthcare provider
Combination therapy with other medications
Long-term management of chronic conditions
Short-term treatment of acute symptoms

Dosage and Administration

Diltiazem dosing varies based on the specific condition being treated and individual patient factors.

Typical Dosing:

Starting dose is typically determined by your healthcare provider
May be adjusted based on response and tolerability
Can be taken with or without food (follow specific instructions)
Usually taken once or twice daily

Administration Tips:

Take at the same time(s) each day for best results
Swallow tablets/capsules whole unless instructed otherwise
Don't skip doses
Complete full course of treatment as prescribed
Follow your doctor's specific instructions carefully

Important Safety Information

Who Should Not Take Diltiazem?

Do not take Diltiazem if you:

Are allergic to Diltiazem or any ingredients
Have certain medical conditions (discuss with your doctor)
Are taking medications that interact with Diltiazem
Have severe liver or kidney disease (without dose adjustment)

Drug Interactions

Inform your doctor about all medications you take, including:

Prescription medications
Over-the-counter drugs
Vitamins and supplements
Herbal products

Some medications may interact with Diltiazem, affecting its efficacy or increasing side effect risk.

Pregnancy and Breastfeeding

Pregnancy:

Discuss risks and benefits with your doctor if pregnant or planning pregnancy
May require special monitoring or dose adjustments
Some medications should be avoided during pregnancy

Breastfeeding:

Consult your doctor about safety while breastfeeding
May pass into breast milk
Benefits and risks should be carefully considered

Monitoring and Follow-Up

While taking Diltiazem, your doctor may monitor:

Effectiveness of treatment (symptom improvement)
Side effects or adverse reactions
Laboratory values if applicable
Blood pressure, heart rate, or other vital signs as appropriate
Overall response to therapy

Regular follow-up appointments are important to ensure the medication is working properly and to make any necessary adjustments.

Managing Side Effects

Most side effects are mild and improve with time. Here are strategies for common side effects:

Gastrointestinal Upset

Take with food if allowed
Stay well hydrated
Eat smaller, more frequent meals
Report persistent nausea or vomiting

Dizziness

Rise slowly from sitting or lying positions
Avoid sudden movements
Stay hydrated
Avoid alcohol
Report severe or persistent dizziness

Fatigue

Get adequate rest
Maintain regular sleep schedule
Exercise as tolerated
Report excessive tiredness that interferes with daily activities

Lifestyle Considerations

To maximize the benefits of Diltiazem:

Follow a healthy, balanced diet
Exercise regularly as recommended by your doctor
Maintain a healthy weight
Avoid alcohol or limit consumption
Don't smoke
Manage stress through relaxation techniques
Get adequate sleep
Stay well hydrated
Keep all follow-up appointments
Take medication consistently as prescribed

When to Contact Your Doctor

Seek immediate medical attention if you experience:

Signs of severe allergic reaction (difficulty breathing, severe rash, swelling)
Chest pain or rapid heartbeat
Severe dizziness or fainting
Unusual bleeding or bruising
Signs of liver problems (yellowing of skin/eyes, dark urine, severe fatigue)
Severe stomach pain
Any symptoms that concern you

Contact your doctor for non-emergency issues:

Mild to moderate side effects that persist
Questions about your medication
Concerns about effectiveness
New medications prescribed by another doctor
Scheduled surgery or dental procedures
Planning pregnancy

Storage

Store Diltiazem at room temperature (68-77°F or 20-25°C) away from light, heat, and moisture. Keep in original container. Keep out of reach of children and pets. Do not use past expiration date.

Important Reminders

Take exactly as prescribed by your doctor
Don't stop suddenly without medical advice
Keep all follow-up appointments
Report any unusual symptoms
Don't share medication with others
Store safely away from children
Check expiration dates
Ask your pharmacist if you have questions

Clinical Benefits

When used appropriately, Diltiazem provides several benefits:

Effective management of high blood pressure, chest pain, and certain heart rhythm disorders
Improvement in quality of life
Reduction in symptoms
Prevention of complications
Generally well-tolerated when used as directed
Backed by clinical research and extensive use

Disclaimer: This information is for educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified healthcare provider with any questions about a medical condition or medication.

Frequently Asked Questions

Immediate-release tablets are taken three to four times a day and produce more variable blood levels — useful when rapid titration is needed but inconvenient long-term. Extended-release capsules deliver steady drug levels with once- or twice-daily dosing, improving adherence and providing smoother blood pressure and heart rate control. Most chronic outpatients use the extended-release form.

Grapefruit juice inhibits the CYP3A4 enzyme in your intestine, which normally breaks down a portion of diltiazem before it reaches the bloodstream. Drinking grapefruit juice can substantially raise diltiazem blood levels, increasing the risk of low blood pressure, slow heart rate, and dizziness. Avoid grapefruit and grapefruit juice while taking this medication.

Yes. Peripheral edema — usually ankle and lower-leg swelling — is one of the more common side effects of all calcium channel blockers, including diltiazem. It is dose-dependent and results from preferential dilation of arterioles over venules. Mild swelling can often be managed with leg elevation; persistent or worsening edema should be reported to your provider.

Diltiazem should generally be avoided in patients with heart failure with reduced ejection fraction (HFrEF) because its negative inotropic effect can worsen heart function. It may be used cautiously in heart failure with preserved ejection fraction (HFpEF), particularly for rate control in atrial fibrillation, but always under specialist supervision.

Diltiazem slows conduction through the AV node, which is part of how it controls atrial fibrillation and supraventricular tachycardia. A resting heart rate persistently below 50 beats per minute, dizziness, lightheadedness, or fainting may indicate excessive bradycardia and should prompt a call to your provider for dose adjustment.

Questions to Ask Your Doctor

Consider discussing these topics at your next appointment:

✓Is diltiazem the best calcium channel blocker for my specific condition, or would amlodipine be more appropriate?
✓How often should I check my blood pressure and pulse at home, and what readings should prompt me to call you?
✓Are any of my current medications, especially statins or beta-blockers, going to interact with diltiazem?
✓What symptoms of side effects should I watch for, and which ones are urgent?
✓How will we know if diltiazem is controlling my condition well enough?

Schedule an Appointment

Related Health Conditions

This medication is commonly used to treat or manage the following conditions:

Attention Deficit Hyperactivity Disorder (ADHD)

ADHD is a neurodevelopmental disorder marked by inattention, hyperactivity, and/or impulsivity, stemming from complex interactions between genetics, brain differences, and environmental factors, not poor parenting.

Learn More

Lupus Anticoagulant

Lupus anticoagulant is an antibody causing paradoxical prolonged clotting tests yet increasing thrombosis risk, linked to antiphospholipid syndrome and autoimmune diseases, despite not always requiring lupus diagnosis.

Learn More

Portal Hypertension

Portal hypertension, an elevated pressure in the portal vein due to blockage often from cirrhosis or other pre-hepatic causes, can lead to serious complications like bleeding and ascites.

Learn More

Secondary Pulmonary Hypertension

Secondary pulmonary hypertension, unlike its primary form, arises from underlying conditions such as heart/lung disease, blood clots, or connective tissue disorders, increasing lung artery pressure.

Learn More

Vertigo

Vertigo, a spinning sensation distinct from dizziness, often stems from inner ear or brain issues like BPPV or Meniere's, sometimes triggered by head trauma or medication.

Learn More

Medical Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication. Your doctor can provide personalized recommendations based on your specific health condition and medical history.