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Diltiazem ER 420mg Tablets

Manufacturer OCEANSIDE PHARMACEUTICALS Active Ingredient Diltiazem Long-Acting Tablets(dil TYE a zem) Pronunciation dil TYE a zem
It is used to treat high blood pressure.It is used to treat some types of chest pain (angina).It may be given to you for other reasons. Talk with the doctor.
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Drug Class
Antihypertensive, Antianginal, Antiarrhythmic
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Pharmacologic Class
Calcium Channel Blocker (Non-dihydropyridine)
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Pregnancy Category
Category C
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FDA Approved
Jan 1970
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DEA Schedule
Not Controlled

Overview

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What is this medicine?

Diltiazem ER 420mg is a medication used to treat high blood pressure (hypertension), chest pain (angina), and sometimes to control heart rate in certain irregular heart rhythms. It works by relaxing blood vessels and slowing down the heart, which helps blood flow more easily and reduces the heart's workload. This is an extended-release tablet, meaning it releases the medicine slowly over 24 hours, so it's usually taken once a day.
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How to Use This Medicine

Taking Your Medication Correctly

To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely.

Take your medication as directed by your doctor, swallowing the tablets whole without chewing, breaking, or crushing them.
 Establish a routine by taking your medication at the same time every day.
Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start feeling well.

Storing and Disposing of Your Medication

To maintain the effectiveness and safety of your medication:

 Store it at room temperature, protected from light and moisture.
Keep it in a dry place, avoiding storage in bathrooms.
 Keep all medications in a secure location, out of the reach of children and pets.
* Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. Check with your pharmacist for guidance on the best disposal method, and consider participating in drug take-back programs in your area.

What to Do If You Miss a Dose

If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Avoid taking two doses at the same time or taking extra doses.
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Lifestyle & Tips

  • Take the medication exactly as prescribed, usually once daily, at approximately the same time each day.
  • Swallow the tablet whole; do not crush, chew, or divide it.
  • Do not stop taking the medication suddenly without consulting your doctor, as this can worsen your condition.
  • Monitor your blood pressure and heart rate regularly as advised by your doctor.
  • Maintain a healthy lifestyle, including a balanced diet (low in sodium and saturated fats), regular exercise, and stress management.
  • Limit alcohol consumption, as it can lower blood pressure and increase dizziness.
  • Avoid grapefruit and grapefruit juice, as they can increase the levels of diltiazem in your body.
  • Inform your doctor or dentist that you are taking diltiazem before any surgery or dental procedures.
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Available Forms & Alternatives

Available Strengths:

Dosing & Administration

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Adult Dosing

Standard Dose: For hypertension: Diltiazem ER 420mg once daily. For angina: Diltiazem ER 420mg once daily.
Dose Range: 120 - 540 mg

Condition-Specific Dosing:

hypertension: Initial dose typically 180-240mg once daily, titrate up to 420mg once daily based on response.
chronic stable angina: Initial dose typically 120-180mg once daily, titrate up to 420mg once daily based on response.
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Pediatric Dosing

Neonatal: Not established
Infant: Not established
Child: Not established
Adolescent: Not established
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Dose Adjustments

Renal Impairment:

Mild: No specific dosage adjustment generally required, monitor closely.
Moderate: No specific dosage adjustment generally required, monitor closely.
Severe: Use with caution, monitor for exaggerated effects. Consider lower initial doses and slower titration.
Dialysis: Diltiazem is not significantly removed by hemodialysis. No specific adjustment, but monitor closely.

Hepatic Impairment:

Mild: Use with caution, monitor for exaggerated effects.
Moderate: Use with caution, consider lower initial doses and slower titration due to prolonged half-life.
Severe: Contraindicated in severe hepatic impairment. Use with extreme caution, if at all, with significant dose reduction and close monitoring.

Pharmacology

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Mechanism of Action

Diltiazem is a non-dihydropyridine calcium channel blocker. It inhibits the influx of extracellular calcium ions across the cell membranes of myocardial and vascular smooth muscle cells. This leads to relaxation of vascular smooth muscle, resulting in vasodilation and a reduction in peripheral vascular resistance (afterload). In the heart, it decreases myocardial contractility, slows sinoatrial (SA) node automaticity, and prolongs atrioventricular (AV) node conduction, leading to a reduction in heart rate and myocardial oxygen demand.
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Pharmacokinetics

Absorption:

Bioavailability: Approximately 40-65% (due to extensive first-pass metabolism)
Tmax: 3-6 hours (for ER formulations)
FoodEffect: Food may increase bioavailability and delay Tmax for some ER formulations, but generally can be taken with or without food.

Distribution:

Vd: Approximately 5.3 L/kg
ProteinBinding: 70-80%
CnssPenetration: Limited

Elimination:

HalfLife: 5-8 hours (for ER formulations, can be longer with chronic dosing)
Clearance: Approximately 1.1 L/min
ExcretionRoute: Primarily renal (60-65% as metabolites, 2-4% as unchanged drug), also fecal (35% as metabolites)
Unchanged: 2-4%
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Pharmacodynamics

OnsetOfAction: Within 30-60 minutes (for ER formulations)
PeakEffect: 3-6 hours (for ER formulations)
DurationOfAction: 24 hours (for once-daily ER formulations)
Confidence: Medium

Safety & Warnings

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Side Effects

Important Side Effects to Report to Your Doctor Immediately

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, seek medical attention right away:

Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
 Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Severe dizziness or fainting
 Slow heartbeat
New or worsening abnormal heartbeat
 Worsening heart failure (if you have a history of heart failure), characterized by:
+ Shortness of breath
+ Significant weight gain
+ Swelling in the arms or legs
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Other severe skin reactions, which may be life-threatening
+ Signs of severe skin reactions include:
- Red, swollen, blistered, or peeling skin
- Skin irritation (with or without fever)
- Red or irritated eyes
- Sores in the mouth, throat, nose, or eyes

Other Possible Side Effects

Most people do not experience severe side effects, and many have no side effects or only minor ones. However, if you notice any of the following side effects or any other unusual symptoms, contact your doctor for advice:

 Headache
* Feeling dizzy, tired, or weak

This is not an exhaustive list of possible side effects. If you have concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
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Seek Immediate Medical Attention If You Experience:

  • Severe dizziness or lightheadedness, especially when standing up
  • Fainting spells
  • Very slow heart rate (e.g., less than 50 beats per minute)
  • New or worsening swelling in your hands, ankles, or feet
  • Shortness of breath, especially with exertion or lying down
  • Unusual fatigue or weakness
  • Yellowing of the skin or eyes (jaundice)
  • Dark urine or pale stools (signs of liver problems)
  • Severe headache that is unusual or persistent
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Before Using This Medicine

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction and its symptoms.
 Certain types of abnormal heart rhythms, as this medication is not suitable for individuals with these conditions. If you are unsure, consult your doctor or pharmacist for guidance.
Specific health conditions, including:
+ Fluid accumulation in the lungs
+ Low blood pressure
+ Recent heart attack
 If you are currently taking any of the following medications:
+ Ivabradine
+ Rifampin

Please note that this is not an exhaustive list of all potential interactions. It is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist to ensure safe use. Before starting, stopping, or adjusting the dosage of any medication, always consult with your doctor to confirm it is safe to do so.
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Precautions & Cautions

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.

When starting this medication, be cautious when performing tasks that require alertness, such as driving, until you understand how it affects you. To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying position, and exercise caution when navigating stairs.

As directed by your doctor, regularly monitor your blood pressure and heart rate. You may need to undergo an electrocardiogram (ECG) before initiating treatment with this medication and at intervals during treatment. Discuss any concerns or questions with your doctor.

If you have high blood pressure and are taking this medication, consult your doctor before using over-the-counter (OTC) products that may increase blood pressure, such as cough or cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and certain natural products or aids.

If you consume grapefruit juice or eat grapefruit regularly, discuss this with your doctor. Additionally, talk to your doctor before consuming alcohol while taking this medication.

If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.

If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby.
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Overdose Information

Overdose Symptoms:

  • Profound hypotension (very low blood pressure)
  • Severe bradycardia (very slow heart rate)
  • AV block (heart block)
  • Asystole (cardiac arrest)
  • Cardiogenic shock
  • Dizziness
  • Confusion
  • Lethargy
  • Coma

What to Do:

Seek immediate medical attention. Call 911 or your local emergency number. For poison control, call 1-800-222-1222. Treatment may involve gastric lavage, activated charcoal, IV fluids, atropine, calcium gluconate, vasopressors, glucagon, or cardiac pacing.

Drug Interactions

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Contraindicated Interactions

  • Ivabradine (risk of severe bradycardia)
  • Dantrolene (IV) (risk of cardiovascular collapse)
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Major Interactions

  • Beta-blockers (e.g., metoprolol, carvedilol) - increased risk of bradycardia, AV block, heart failure
  • Digoxin - increased digoxin levels, risk of toxicity
  • Amiodarone - increased risk of bradycardia, AV block, hypotension
  • Statins (e.g., simvastatin, lovastatin) - increased statin levels, risk of myopathy/rhabdomyolysis
  • Fentanyl (CYP3A4 substrate) - increased fentanyl levels, respiratory depression
  • Midazolam, Triazolam (CYP3A4 substrates) - increased benzodiazepine levels, prolonged sedation
  • Cyclosporine, Tacrolimus, Sirolimus (calcineurin inhibitors) - increased immunosuppressant levels, nephrotoxicity
  • Alpha-blockers (e.g., prazosin, doxazosin) - increased risk of hypotension
  • Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, ritonavir) - increased diltiazem levels
  • Strong CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin, St. John's Wort) - decreased diltiazem levels
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Moderate Interactions

  • Clonidine - additive bradycardia/hypotension
  • Quinidine - increased quinidine levels
  • Theophylline - increased theophylline levels
  • Phenytoin - increased phenytoin levels
  • Grapefruit juice - may increase diltiazem levels
  • Cimetidine - increased diltiazem levels
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Minor Interactions

  • Not available

Monitoring

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Baseline Monitoring

Blood Pressure (BP)

Rationale: To establish baseline and guide initial dosing for hypertension/angina.

Timing: Prior to initiation

Heart Rate (HR)

Rationale: To establish baseline and assess risk of bradycardia.

Timing: Prior to initiation

Electrocardiogram (ECG)

Rationale: To assess baseline cardiac rhythm, PR interval, and rule out pre-existing conduction abnormalities.

Timing: Prior to initiation, especially if pre-existing cardiac conditions

Liver Function Tests (LFTs)

Rationale: Diltiazem is extensively metabolized by the liver; to assess baseline hepatic function.

Timing: Prior to initiation

Renal Function Tests (Creatinine, BUN)

Rationale: To assess baseline renal function.

Timing: Prior to initiation

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Routine Monitoring

Blood Pressure (BP)

Frequency: Regularly, e.g., weekly initially, then monthly or every 3-6 months once stable

Target: <130/80 mmHg (or individualized target)

Action Threshold: If BP remains uncontrolled or becomes excessively low (e.g., <90/60 mmHg)

Heart Rate (HR)

Frequency: Regularly, e.g., weekly initially, then monthly or every 3-6 months once stable

Target: 50-90 bpm (or individualized target)

Action Threshold: If HR <50 bpm or symptomatic bradycardia

Electrocardiogram (ECG)

Frequency: Periodically, especially if dose increased or symptoms of conduction disturbance

Target: Normal sinus rhythm, PR interval <0.20 sec

Action Threshold: New onset of AV block (2nd or 3rd degree), significant bradycardia, or other arrhythmias

Liver Function Tests (LFTs)

Frequency: Periodically, e.g., every 6-12 months or if symptoms of hepatic dysfunction

Target: Within normal limits

Action Threshold: Significant elevation of liver enzymes (e.g., >3x ULN)

Signs/Symptoms of Heart Failure

Frequency: At each visit

Target: Absence of new or worsening dyspnea, edema, fatigue

Action Threshold: Development or worsening of heart failure symptoms

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Symptom Monitoring

  • Dizziness
  • Lightheadedness
  • Fatigue
  • Swelling in ankles/feet (edema)
  • Shortness of breath
  • Chest pain (angina)
  • Palpitations
  • Bradycardia (slow heart rate)
  • Headache
  • Nausea
  • Constipation

Special Patient Groups

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Pregnancy

Diltiazem is Pregnancy Category C. Animal studies have shown adverse effects on the fetus, but there are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Trimester-Specific Risks:

First Trimester: Potential for teratogenicity observed in animal studies (skeletal abnormalities, embryolethality at high doses).
Second Trimester: Risk of fetal bradycardia and hypotension.
Third Trimester: Risk of fetal bradycardia and hypotension; potential for prolonged labor due to uterine relaxation.
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Lactation

Diltiazem is excreted in breast milk. The American Academy of Pediatrics considers it compatible with breastfeeding, but caution is advised. Monitor the infant for bradycardia, hypotension, and sedation.

Infant Risk: L3 (Moderately Safe) - Monitor infant for adverse effects, especially bradycardia and hypotension. Consider alternative if infant is premature or has underlying cardiac issues.
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Pediatric Use

Safety and effectiveness in pediatric patients have not been established. Use is generally not recommended.

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Geriatric Use

Elderly patients may be more sensitive to the hypotensive and bradycardic effects of diltiazem due to age-related decreases in renal and hepatic function. Start with lower doses and titrate slowly, monitoring closely for adverse effects.

Clinical Information

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Clinical Pearls

  • Diltiazem ER 420mg is a high dose and typically used for patients requiring significant blood pressure or heart rate control, or those who have not responded to lower doses.
  • Always swallow ER tablets whole; crushing or chewing can lead to rapid release and potentially dangerous overdose.
  • Monitor heart rate closely, especially when co-administered with other negative chronotropes (e.g., beta-blockers, digoxin).
  • Be aware of significant drug interactions, particularly with CYP3A4 substrates (e.g., statins, immunosuppressants) and inhibitors/inducers.
  • Patients should be advised to report symptoms of bradycardia (dizziness, fatigue, syncope) or heart failure (shortness of breath, edema).
  • Constipation is a common side effect; advise patients on dietary fiber and hydration.
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Alternative Therapies

  • Other calcium channel blockers (e.g., amlodipine, verapamil, felodipine)
  • Beta-blockers (e.g., metoprolol, atenolol)
  • ACE inhibitors (e.g., lisinopril, enalapril)
  • Angiotensin Receptor Blockers (ARBs) (e.g., losartan, valsartan)
  • Thiazide diuretics (e.g., hydrochlorothiazide)
  • Other antiarrhythmics (e.g., amiodarone, flecainide for rate/rhythm control)
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Cost & Coverage

Average Cost: Varies widely, typically $50-$300+ per 30 tablets
Generic Available: Yes
Insurance Coverage: Tier 1 or Tier 2 (Generic)
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General Drug Facts

If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.